Riamet^® Tablets

MIMS Revision Date: 01 September 2020

1 Name of Medicine

Artemether and lumefantrine.

2 Qualitative and Quantitative Composition

Riamet tablets and Riamet Dispersible tablets contain the active ingredient artemether and lumefantrine.
Riamet tablets. Excipients with known effect. Sugars and latex (in trace amounts).
Riamet Dispersible tablets. Excipients with known effect. Sugars and latex (in trace amounts).
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Riamet tablets (20 mg/120 mg). Tablets.
Riamet Dispersible tablets (20 mg/120 mg). Dispersible tablets.

4 Clinical Particulars

4.1 Therapeutic Indications

Riamet tablet is indicated for the treatment of acute, uncomplicated malaria due to Plasmodium falciparum in adults, children and infants of 5 kg and above.
Riamet Dispersible tablet is indicated for the treatment of acute, uncomplicated malaria due to Plasmodium falciparum in children and infants weighing between 5 kg and less than 35 kg.

4.2 Dose and Method of Administration

Dosage regimen. Riamet Dispersible tablets for infants and children weighing 5 kg to < 35 kg, and aged ≥ 3 months up to 12 years. Six doses of 1 to 3 dispersible tablets per dose, depending on bodyweight (i.e. total course of either 6, 12, or 18 tablets), given over a period of 60 hours.
5 to < 15 kg bodyweight, and ≥ 3 months. One dispersible tablet at the time of initial diagnosis, 1 tablet again after 8 hours and then 1 tablet twice daily (morning and evening) on each of the following two days (total course comprises 6 tablets).
15 to < 25 kg bodyweight. Two dispersible tablets as a single dose at the time of initial diagnosis, 2 tablets again after 8 hours and then 2 tablets twice daily (morning and evening) on each of the following two days (total course comprises 12 tablets).
25 to < 35 kg bodyweight, and < 12 years. Three dispersible tablets as a single dose at the time of initial diagnosis, 3 tablets again after 8 hours and then 3 tablets twice daily (morning and evening) on each of the following two days (total course comprises 18 tablets).
Riamet tablets for adults, adolescents, and children weighing ≥ 35 kg or > 12 years of age. Six doses of four tablets (i.e. total course of 24 tablets), given over a period of 60 hours.
Elderly. Although no studies have been carried out in the elderly, no special precautions or dosage adjustments are considered necessary in such patients.
Renal or hepatic impairment. Although no specific studies have been carried out, no dosage adjustments are considered necessary for these conditions.
No specific dose adjustment recommendations can also be made for patients with hepatic impairment (see Section 4.4 Special Warnings and Precautions for Use). Most patients with acute malaria present with some degree of related hepatic impairment. The adverse event profile did not differ in patients with and those without hepatic impairment. Moreover, baseline abnormalities in liver function tests improved in nearly all patients after treatment.
New and recrudescent infections. Data for a limited number of patients show that new and recrudescent infections can be treated with a second course of Riamet. In the absence of carcinogenicity study data, and due to lack of clinical experience, more than two courses of Riamet cannot be recommended.
Method of administration. The first dose, given at the time of initial diagnosis, should be followed by five further doses given at 8, 24, 36, 48 and 60 hours thereafter. Whenever possible, the dose should be taken immediately after food. Patients with acute malaria are frequently averse to food. Patients should be encouraged to resume normal eating as soon as food can be tolerated since this improves absorption of artemether and lumefantrine (see Section 5.2 Pharmacokinetic Properties, Absorption). In the event of vomiting within 1 hour of administration, a repeat dose should be taken.
Riamet Dispersible tablets for infants and children weighing 5 kg to < 35 kg, and aged ≥ 3 months up to 12 years. The dispersible tablet(s) composing 1 dose should be completely dispersed in a small amount of water (approximately 10 mL per tablet). Stir gently and administer immediately to the patient. Rinse the glass with an additional small amount of water (approximately 10 mL) and give immediately to the patient.
Riamet tablets for adults, adolescents, and children weighing ≥ 35 kg or > 12 years of age. Swallow the tablets whole. The tablets may be taken with fluids.

4.3 Contraindications

Riamet and Riamet Dispersible tablets are contraindicated in:
Patients with known hypersensitivity to artemether or lumefantrine or any of the excipients.
Patients with severe malaria according to the World Health Organization definition*.
Patients who are taking any drug which is metabolised by the cytochrome enzyme CYP2D6 (e.g. flecainide, metoprolol, imipramine, amitriptyline, clomipramine).
Patients who are taking any drug metabolised by strong inducers of CYP3A4 (e.g. rifampicin, carbamazepine, phenytoin, St John's wort (Hypericum perforatum)) (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Patients with known pre-existing prolongation of the QTc interval (see Section 4.4 Special Warnings and Precautions for Use; Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Patients with a family history of congenital prolongation of the QTc interval on electrocardiograms or of sudden death or with any other clinical condition known to prolong the QTc interval such as patients with a history of symptomatic cardiac arrhythmias, with clinically relevant bradycardia or with severe cardiac disease.
Patients taking drugs that are known to prolong the QTc interval such as:
antiarrhythmics of classes IA and III;
neuroleptics, antidepressant agents;
certain antibiotics including some agents of the following classes: macrolides, fluoroquinolones, imidazole, and triazole antifungal agents;
certain nonsedating antihistamines (terfenadine, astemizole);
cisapride.
Patients with known disturbances of electrolyte balance, e.g. hypokalaemia or hypomagnesaemia.
Where * indicates the presence of one or more of the following clinical or laboratory features.
Clinical manifestations. Prostration; impaired consciousness or unarousable coma; failure to feed; deep breathing, respiratory distress (acidotic breathing); multiple convulsions; circulatory collapse or shock; pulmonary oedema (radiological); abnormal bleeding; clinical jaundice; haemoglobinuria.
Laboratory tests. Severe normocytic anaemia; haemoglobinuria; hypoglycaemia; metabolic acidosis; renal impairment; hyperlactatemia; hyperparasitemia.

4.4 Special Warnings and Precautions for Use

Identified precautions. Riamet and Riamet Dispersible tablets have not been evaluated for the treatment of complicated malaria, including cases of cerebral malaria or other severe manifestations such as pulmonary oedema or renal failure.
Riamet and Riamet Dispersible tablets are not indicated for, and have not been evaluated in, the treatment of malaria due to P. vivax, P. malariae or P. ovale, although some patients in clinical studies had co-infection with P. falciparum and P. vivax at baseline. Riamet and Riamet Dispersible tablets are active against blood stages of P. vivax, but is not active against hypnozoites. Riamet and Riamet Dispersible tablets are not indicated and have not been evaluated for prophylaxis.
Patients who remain averse to food during treatment should be closely monitored as the risk of recrudescence may be greater.
The exposure to artemether in Riamet Dispersible tablets and Riamet tablets are not bioequivalent (see Section 5.2 Pharmacokinetic Properties).
Riamet should not be used in the first trimester of pregnancy in situations where other suitable and effective antimalarials are available (see Section 4.6 Fertility, Pregnancy and Lactation).
QTc interval prolongation. Halofantrine, quinine and quinidine are known to cause QTc interval prolongation. Like other antimalarials (e.g. halofantrine, quinine and quinidine), Riamet and Riamet Dispersible tablets have the potential to cause QTc interval prolongation with standard dosing, although no clinical adverse event attributable to QTc prolongation (e.g. syncope, sudden death) has been reported. Asymptomatic prolongation of QTc intervals by > 30 milliseconds, with an actual QTc > 450 milliseconds in males and > 470 milliseconds in females, was observed in approximately 7% of patients treated with various dose regimens of Riamet in clinical trials. It is possible that these changes were disease related. No correlation has been found between QTc interval prolongation and plasma concentrations of artemether, dihydroartemisinin or lumefantrine.
Due to the lack of clinical data and due to the propensity of some antimalarial agents to prolong the QTc interval, caution is advised when administering Riamet or Riamet Dispersible tablets to patients in whom there may be detectable concentrations of these drugs in the plasma following prior treatments (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Due to the lack of data on safety and efficacy, Riamet or Riamet Dispersible tablets should not be given concurrently with any other antimalarial agents. However, if a patient deteriorates whilst taking Riamet or Riamet Dispersible tablets and requires alternative treatment, this should be commenced without delay, but with caution. ECG and blood potassium monitoring are recommended.
Use in hepatic impairment. Neither Riamet nor Riamet Dispersible tablets have been studied for efficacy and safety in patients with severe hepatic insufficiency and therefore no recommendations can be made for this group of patients. In patients with severe hepatic impairment, a clinically relevant increase of exposure to artemether and lumefantrine and/or their metabolites cannot be ruled out. Therefore caution should be exercised in dosing patients with severe hepatic impairment (see Section 5.2 Pharmacokinetic Properties).
Use in renal impairment. Neither Riamet nor Riamet Dispersible tablets have been studied for efficacy and safety in patients with severe renal insufficiency and therefore no recommendations can be made for this group of patients.
Use in patient with cardiac impairment. Caution is advised when administering Riamet or Riamet Dispersible tablets to patients with severe cardiac disease. In these patients, ECG and blood potassium monitoring is advised.
Use in the elderly. There is no information suggesting that the dosage in patients under 65 years of age should be different to younger adults (see Section 5.2 Pharmacokinetic Properties; Section 4.2 Dose and Method of Administration).
Paediatric use. The efficacy of Riamet Dispersible tablet was based on a study population including 1 infant < 3 months of age and the safety data was based on a population including 4 patients less than 3 months of age only one of whom was treated with Riamet Dispersible tablets. (See Section 5.1 Pharmacodynamic Properties, Clinical trials). The safety and efficacy of Riamet or Riamet Dispersible tablets in children aged less than 3 months have not been adequately assessed.
Carcinogenicity, mutagenicity and impairment of fertility. Carcinogenicity studies with Riamet or Riamet Dispersible tablets were not conducted. Neither artemether, lumefantrine or the combination were mutagenic in bacteria, nor were they mutagenic or clastogenic in V79 Chinese hamster ovary cells in vitro, and they did not induce micronuclei in bone marrow erythrocytes of rats following an oral dose of Riamet up to 2000 mg/kg.
Use with other drugs. Caution is recommended when combining Riamet with substrates, inhibitors or weak to moderate inducers of CYP3A4 as the therapeutic effects of some drugs could be altered. Drugs that have a mixed inhibitory/induction effect on CYP3A4, especially antiretroviral drugs such as HIV protease inhibitors and non-nucleoside reverse transcriptase inhibitors should be used with caution in patients taking Riamet (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions; Section 5.2 Pharmacokinectic Properties).

4.5 Interactions with Other Medicines and Other Forms of Interactions

Interactions resulting in a contraindication. Drugs that are known to prolong the QTc interval. Riamet is contraindicated with concomitant use of drugs (they may cause prolonged QTc interval and torsades de pointes) such as: antiarrhythmics of classes IA and III, neuroleptics and antidepressant agents, certain antibiotics including some agents of the following classes: macrolides, fluoroquinolones, imidazole, and triazole antifungal agents, certain nonsedating antihistamines (terfenadine, astemizole), and cisapride (see Section 4.3 Contraindications).
Drugs metabolized by CYP2D6. Lumefantrine was found to inhibit CYP2D6 in vitro. This may be of particular clinical relevance for compounds with a low therapeutic index. Coadministration of Riamet with drugs which are metabolised by this iso-enzyme is contraindicated (e.g. neuroleptics, flecainide, metoprolol, and tricyclic antidepressants such as imipramine, amitriptyline, clomipramine) (see Section 4.3 Contraindications; Section 5.2 Pharmacokinetic Properties).
Interaction with strong inducers of CYP3A4 such as rifampicin. Oral administration of 600 mg rifampicin daily, a strong CYP3A4 inducer, with Riamet Tablets (6-dose regimen over 3 days) resulted in significant decreases in exposure to artemether, DHA and lumefantrine when compared to exposure values after Riamet alone. Concomitant use of strong inducers of CYP3A4 such as rifampicin, carbamazepine, phenytoin, St John's wort is contraindicated with Riamet (see Section 4.3 Contraindications).
Interactions resulting in concomitant use not being recommended. Other antimalarials. Data on safety and efficacy are limited, and Riamet should therefore not be given concurrently with other antimalarials unless there is no other treatment option (see Section 4.4 Special Warnings and Precautions for Use). If Riamet is given following administration of mefloquine or quinine, close monitoring of food intake (for mefloquine) or of the ECG (for quinine) is advised. The long elimination half-life of lumefantrine must be taken into account when administering quinine in patients previously treated with Riamet.
In vitro studies indicated that lumefantrine metabolism is inhibited by halofantrine and quinine (also see interaction study with quinine in healthy volunteers above).
Due to the lack of clinical data, and due also to the propensity of some antimalarials to prolong the QTc interval, caution is advised when administering Riamet or Riamet Dispersible tablets to patients in whom there may be detectable concentrations of these drugs in the plasma following prior treatments.
In particular, Riamet or Riamet Dispersible tablets must not be coadministered with halofantrine (see Section 4.3 Contraindications; Section 4.4 Special Warnings and Precautions for Use). In patients previously treated with halofantrine, Riamet should be dosed at least one month after the last halofantrine dose.
Drug-drug interaction studies. Three specific pharmacokinetic and pharmacodynamic drug-drug interaction studies with ketoconazole (a potent CYP3A4 inhibitor), quinine and mefloquine have been conducted in healthy volunteers.
Ketoconazole. Sixteen healthy adults were randomised in an open-label, two period crossover design study. Subjects received a single Riamet dose (4 tablets, i.e. 80 mg artemether/ 480 mg lumefantrine) either alone or in combination with multiple oral doses of ketoconazole (400 mg on day 1 followed by 200 mg daily for 4 additional days). The concurrent administration of ketoconazole with Riamet led to an increase (maximum 2.3-fold) in artemether, dihydroartemisinin (the main metabolite) and lumefantrine exposure. The mean percent increase in AUC∞ for artemether, dihydroartemisinin and lumefantrine was 131%, 51% and 61%, respectively. This increase in exposure to the antimalarial combination was not associated with increased side effects or changes in electrocardiographic parameters. Based on this study, dose adjustment of Riamet is considered unnecessary in falciparum malaria patients when administered in association with ketoconazole or other potent CYP3A4 inhibitors. The addition of a CYP3A4 inhibitor to a multiple dose course of Riamet has not been studied.
Quinine. The concurrent intravenous administration of quinine (10 mg/kg body weight) with Riamet had no effect on plasma concentrations of lumefantrine or quinine. Plasma concentrations of artemether and the main metabolite, dihydroartemisinin, appeared to be lower. In this study, administration of Riamet to 14 subjects had no effect on QTc interval. Infusion of quinine alone in 14 other subjects caused a transient prolongation of the QTc interval, with the peak QTc interval post dose increasing by 5.5 milliseconds, which is consistent with the known cardiotoxicity of quinine. This effect was slightly, but significantly, greater when quinine was infused after Riamet in 14 additional subjects, with the peak QTc interval postquinine dose increasing by 15.6 milliseconds. It would thus appear that the inherent risk of QTc interval prolongation associated with intravenous quinine was enhanced by prior administration of Riamet.
Mefloquine. A drug interaction study with Riamet in man involved administration of a 6-dose regimen over 60 hours in healthy volunteers, which was commenced at 12 hours after completion of a 3-dose regimen of mefloquine or placebo. Plasma mefloquine concentrations from the time of addition of Riamet were not affected compared with a group who received mefloquine followed by placebo.
Pre-treatment with mefloquine had no effect on plasma concentrations of artemether or the artemether/dihydroartemisinin ratio but there was a significant reduction in plasma levels of lumefantrine, possibly due to lower absorption secondary to a mefloquine-induced decrease in bile production.
Interactions to be considered. Interactions affecting the use of Riamet and Riamet Dispersible. CYP450 enzymes. Both artemether and lumefantrine are metabolised by the cytochrome enzyme CYP3A4 but do not inhibit this enzyme at therapeutic concentrations. Due to the potential for increased concentrations of lumefantrine which could lead to QT prolongation, Riamet should be used cautiously with drugs that inhibit CYP3A4. Grapefruit juice should be avoided during Riamet treatment (see Section 4.4 Special Warnings and Precautions for Use).
Antiretroviral drugs. Due to variable patterns of inhibition, induction or competition for CYP3A4 with protease inhibitor antiretroviral drugs, use of such drugs, especially combinations of them, concomitantly with Riamet requires caution. Both artemether and lumefantrine are metabolized by CYP3A4. Antiretroviral drugs, such as protease inhibitors and non-nucleoside reverse transcriptase inhibitors, are known to have variable patterns of inhibition, induction or competition for CYP3A4. Riamet should be used cautiously in patients on antiretroviral drugs since decreased artemether, DHA, and/or lumefantrine concentrations may result in a decrease of antimalarial efficacy of Riamet, and increased lumefantrine concentrations may cause QT prolongation (see Section 4.4 Special Warnings and Precautions for Use).
Interaction with weak to moderate inducers of CYP3A4. When Riamet is coadministered with weak to moderate inducers of CYP3A4 it may result in decreased concentrations of artemether and/or lumefantrine and loss of antimalarial efficacy (see Section 4.4 Special Warnings and Precautions for Use).
Interactions resulting in effects of Riamet on other drugs. Interaction with drugs metabolized by CYP450 enzymes. When Riamet is coadministered with substrates of CYP3A4, it may result in decreased concentrations of the substrate and potential loss of substrate efficacy. Whereas in vitro studies with artemether at therapeutic concentrations revealed no significant interactions with cytochrome P450 enzymes, the artemisinins have some capacity to induce the production of the cytochrome enzyme CYP2C19, and perhaps also CYP3A4. It is possible that iso-enzyme induction could alter the therapeutic effects of drugs which are predominantly metabolised by these enzymes (see Section 4.4 Special Warnings and Precautions for Use; Section 5.2 Pharmacokinetic Properties).
Hormonal contraceptives. Riamet may reduce the effectiveness of hormonal contraceptives. Therefore, patients using oral, transdermal patch, or other systemic hormonal contraceptives should be advised to use an additional nonhormonal method of birth control (see Section 4.4 Special Warnings and Precautions for Use).
Drug-food/drink interactions. Riamet should be taken with food or drinks rich in fat such as milk as the absorption of both artemether and lumefantrine is increased (see Section 4.2 Dose and Method of Administration).
Grapefruit juice should be avoided during Riamet and/or Riamet Dispersible treatment.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility. There are no human data addressing the effects of Riamet or Riamet Dispersible tablets on fertility. In a reproductive toxicity study in rats, Riamet had no effects on male or female fertility at an oral dose up to 300 mg/kg/day, corresponding to an estimated systemic exposure to lumefantrine (based on AUC) of 4.7-47 x and an artemether dose of 43 mg/kg/day (artemether exposures could not be estimated due to an extensive first-pass effect). At 1000 mg/kg/day, Riamet reduced the pregnancy rate by decreasing male fertility (reduced sperm motility and epididymal sperm count, increased percentage of morphologically abnormal sperm).
Use in pregnancy. (Category D)
Artemisinins are known to be embryotoxic and teratogenic in animals, causing cardiovascular and skeletal deformities.
Based on animal data, Riamet is suspected to cause serious birth defects when administered during the first trimester of pregnancy (see Section 4.4 Special Warnings and Precautions for Use).
Human data. A meta-analysis of observational studies including over 500 artemether-lumefantrine exposed women in their first trimester of pregnancy assessed adverse pregnancy outcomes.
For congenital abnormalities, the results of the meta-analysis comparing the effect of artemisinin and quinine with the group unexposed to antimalarial were in Table 1.

Due to limitations of this analysis, the risk of adverse pregnancy outcomes for artemether-lumefantrine exposed women in early pregnancy cannot be excluded.
Safety data from an observational pregnancy study including over 300 pregnant women who were exposed to Riamet during the second or third trimester, and published data of another approximately 500 pregnant women who were exposed to artemether-lumefantrine, as well as published data of over 1,000 pregnant women who were exposed to artemisinin derivatives, did not show an increase in adverse pregnancy outcomes or teratogenic effects over background rates.
In addition, there was no apparent increase in adverse pregnancy outcomes based on data from one open label randomized study of over 800 patients treated with Riamet in the second or third trimester.
Epidemiological studies have important methodological limitations, which hinder interpretation of data, including inability to control for confounders, such as underlying maternal disease, and maternal use of concomitant medications and missing information on the dose and duration of use.
Riamet should not be used during the first trimester of pregnancy in situations where other suitable and effective antimalarials are available.
During the second and third trimester, treatment should only be considered if the expected benefit to the mother outweighs the risk to the fetus.
Use in lactation. Riamet or Riamet Dispersible tablets should not be taken by breast-feeding women as no data on excretion in milk are available. Due to the long elimination half-life of lumefantrine (4 to 6 days), it is recommended that breastfeeding should not resume until at least four weeks after the last dose, unless the potential benefits to the mother and child outweigh the risks of treatment.
There were no data on excretion of artemether, lumefantrine and/or their metabolites in the milk of animals; however distribution studies in pregnant rats suggested retention of the drugs and/or their metabolites in the mammary glands. A peri-postnatal study showed no development changes in rat pups whose mothers received 50 mg/kg/day of Riamet (7.1 mg/kg artemether, 42.9 mg/kg lumefantrine) up to day 21 of lactation.
Women of childbearing potential. As Riamet or Riamet Dispersible tablets are contraindicated during the first trimester of pregnancy, women should not conceive while on this treatment for malaria. This includes women prescribed Riamet, for stand-by emergency treatment of malaria during their travel, in which case an effective form of contraception should be used during travel and until the start of the next menstruation after the treatment.
Women using oral, transdermal patch, or other systemic hormonal contraceptives should be advised to use an additional nonhormonal method of birth control (see Section 4.5).
Embryofoetal development studies were performed in rats and rabbits with oral lumefantrine, artemether, and the combination. Transfer of the drug(s) and/or metabolites to the foetus was demonstrated in both species.
Administration of lumefantrine alone during gestation showed no evidence of maternal or embryofoetal toxicity, nor teratogenicity, at doses up to 1000 mg/kg/day (rats and rabbits), corresponding to approximate systemic exposure ratios (based on AUCs) of 5.3 to 55 times those measured at the maximum recommended clinical dose.
Administration of artemether alone to gestating rats showed no embryofoetal effects at doses up to 3 mg/kg/day. Increased postimplantation loss and decreased foetal bodyweights, but no maternotoxicity, were seen at 10 mg/kg/day. Artemisinins are known to be embryotoxic in animals, causing cardiovascular and skeletal malformations. These effects have been observed in some studies with artemether. In rabbits, there were no maternal or foetal effects at doses up to 25 mg/kg/day, but abortions and increased postimplantation loss occurred at 30 mg/kg/day. Systemic exposures to artemether could not be determined due to an extensive first-pass effect.
Administration of the combination showed no embryofoetal effects in rats at doses up to 30 mg/kg/day (4.3 mg/kg/day artemether), but increased postimplantation losses were seen at 60 mg/kg/day and above. In rabbits, there were no embryofoetal effects at doses up to 105 mg/kg/day (15 mg/kg/day artemether), but increased postimplantation losses and abortions were observed at 175 mg/kg/day (25 mg/kg/day artemether).

4.7 Effects on Ability to Drive and Use Machines

Patients receiving Riamet or Riamet Dispersible tablets should be warned that dizziness or fatigue/ asthenia may occur, in which case they should not drive or use machines.

4.8 Adverse Effects (Undesirable Effects)

Adverse events in clinical trials. Infants and children weighing 5 kg to less than 35 kg and 12 years of age or less. The pooled safety population included 1262 infants and children ≤ 12 years of age and ≥ 5 kg to < 35 kg body weight enrolled in 4 studies who received at least one dose of the assigned 6-dose regimen of Riamet tablets (815) or Riamet Dispersible tablets (447). 96% of the patients were black (studies conducted in Africa) and the remainder were enrolled in studies conducted in Thailand. Only 4 of the 1262 participants were less than 3 months of age.
Riamet and Riamet Dispersible tablets appeared to be well tolerated regardless of the administration form. Most of the reported events were of mild to moderate severity and duration, and likely related to the underlying malaria and/or to an unsatisfactory response to the treatment rather than to Riamet or Riamet Dispersible tablets although a causal relationship could not be excluded for some reports. For other reports, alternative factors were identified as the more likely cause of the events (e.g. concomitant drugs, concomitant infections) or the information provided was too scarce to draw any conclusion.
Adverse reactions are ranked under headings of frequency, the most frequent first, using the following convention: very common (≥ 1/10); common (≥ 1/100, < 1/10); uncommon (≥ 1/1000, < 1/100); rare (≥ 1/10,000, < 1/1000); very rare (< 1/10,000), including isolated reports (see Table 2).

Adverse events found in nonrecommended regimens not included in this pooled safety analysis: paraesthesia (1.2% of adolescents and adults, no cases in children); involuntary muscle contractions (1.3% of children).
The following adverse reactions were reported in adults with a frequency of uncommon but were not reported in infants or children: hypoaesthesia, ataxia, and gait abnormal.
Adolescents and adults. Treatment emergent signs and symptoms occurring with an incidence of ≥ 1% in patients over 12 years of age given the 6 dose regimen (N = 495) are shown in Table 3. These events are not necessarily related to treatment with the drug and may be related to the underlying disease.
Serious adverse events that occurred in patients taking Riamet in clinical trials included isolated reports of haemolytic anaemia, hepatitis and QTc prolongation. Asymptomatic QTc prolongation was reported in adults, children and infants but no causal relationship with Riamet could be confirmed.
A causal relationship with the use of Riamet could not be excluded for the following adverse events.
The adverse events listed in Table 4 represent a pooled safety analysis of adverse reactions from clinical trials in adults and adolescents > 12 years of age or ≥ 35 kg body weight using the recommended 6-dose regimen.
Postmarketing experience. Listing of adverse drug reactions from postmarketing spontaneous reports. Riamet Dispersible. The following additional adverse drug reactions have been identified based on postmarketing spontaneous reports. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency, which is therefore categorised as not known.
Hypersensitivity reactions including urticaria and angioedema have been rarely reported.
Riamet. It is estimated that over 1,250,000 patients have been exposed to Riamet in other countries.
The following additional adverse drug reactions have been identified based on postmarketing spontaneous reports. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency.
The most frequently reported adverse events since marketing include: anaemia NOS*, chromaturia, diarrhoea NOS, face oedema, haemoglobinuria, hypersensitivity NOS reactions including urticaria and angioedema have been rarely reported, hypertension NOS, jaundice NOS, peripheral oedema, pruritus NOS, pyrexia, erythematous rash, thrombocytopenia, vomiting NOS. On the basis of the above-mentioned patient population exposed to the drug, all these events could be classified as "very rare" (< 0.01%).
(*NOS stands for "Not Otherwise Specified" and means that more specific information was not provided).
Many of these events are likely to be related to the underlying malaria and/or to an unsatisfactory response to the treatment. The remaining are isolated reports where other factors were identified as more likely cause of the events (e.g. concomitant drugs, concomitant infections) or where the information provided was too scarce to draw any conclusion.
Adverse events found in nonrecommended regimens not included in the pooled safety analysis: paraesthesia (1.2% of adolescents and adults).
Reporting suspected adverse effects. Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

In cases of suspected overdosage, symptomatic and supportive therapy should be given as appropriate. ECG and electrolytes should be monitored.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action. Riamet and Riamet Dispersible tablets are blood schizontocides comprising a fixed ratio of 1:6 parts of artemether and lumefantrine, respectively. The site of antiparasitic action of both components is the food vacuole of the malarial parasite, where they are thought to interfere with the conversion of haem, a toxic intermediate produced during haemoglobin breakdown, to the nontoxic haemozoin, malaria pigment. Lumefantrine is thought to interfere with the polymerisation process, while artemether generates reactive metabolites as a result of the interaction between its peroxide bridge and haem iron. Both artemether and lumefantrine have a secondary action involving inhibition of nucleic acid synthesis and protein synthesis within the malarial parasite.
The antimalarial activity of the combination of lumefantrine and artemether in Riamet is greater than that of either substance alone. In a double-blind comparative study in China, the 28-day cure rate of Riamet when given as 4 doses was 100%, compared with 92% for lumefantrine and 55% for artemether when given as monotherapy.
In comparative clinical trials, Riamet tablets cleared gametocytes in less than one week and more rapidly than nonartemisinin antimalarial comparators.
Clinical trials. Efficacy data in infants and children. Study B2303 was a phase III, randomised, investigator-blinded, multicentre, parallel-group trial comparing the efficacy, safety, and tolerability of Riamet Dispersible tablet to crushed Riamet tablets, administered according to body weight ranges, in 899 male and female infants and children, weighing between 5 kg and ≤ 35 kg and aged ≤ 12 years, with microscopically confirmed, acute, uncomplicated P. falciparum malaria or with mixed infection including P. falciparum. The study was conducted in eight study centres in Sub-Saharan Africa.
Riamet Dispersible tablet was compared to crushed Riamet tablet rather than another antimalarial, because Riamet is the approved reference treatment for the treatment of uncomplicated falciparum malaria in several endemic and nonendemic countries in this patient population.
The primary efficacy variable was the proportion of patients who were clinically free of parasitemia (PCR corrected if P. falciparum asexual forms present) at 28 days as measured by PCR corrected parasitological cure rate (see Table 5). Baseline demographics characteristics are presented in Table 6.

In an open, multicentre clinical study conducted in Africa in 310 children weighing ≥ 5 kg to ≤ 25 kg and receiving a 6-dose Riamet according to body weight ranges, the mean 28-day parasitological cure rate (PCR corrected) was 93.9% for the ITT population and 96.7% for the evaluable population.
Children from nonendemic countries were not included in clinical trials.
Efficacy data in adults. Active-controlled trials. Three randomised, parallel group studies using the recommended 6-dose regimen were conducted in Thailand. One study (Study 025) compared the efficacy and safety of a 4-dose regimen of Riamet tablets with two 6-dose Riamet tablet regimens (6 doses over 3 days or 6 doses over 5 days). The other two studies (Studies 026 and 028) compared 6 doses of Riamet tablets over 3 days with mefloquine 15 mg/kg on Day 2 and 10 mg/kg on Day 3 + artesunate 4 mg/kg od for 3 days (MAS). In all three studies the primary efficacy criteria was the cure rate at Day 28. Time to parasite clearance was a secondary measure of efficacy. For the 385 evaluable patients given Riamet, the cure rate at Day 28 was 96.4% (95% CI 94.0, 98.0). Parasite clearance had occurred in 32.2% of patients by Day 2 and in 88.2% of patients by Day 3.
Another study conducted in Thailand (Study 008) compared the 4 dose regimen of Riamet tablets with MAS. For the 364 evaluable patients given MAS the cure rate at Day 28 was 98.1% (95% CI 96.1, 99.2). Parasite clearance had occurred in 55.2% of patients by Day 2 and in 84.0% of patients by Day 3. In the two studies where Riamet was compared with MAS, parasite clearance rates at Day 2 and Day 3 were comparable. Cure rates in patients given Riamet were negatively affected by high parasite density at baseline, high body weight and no food before the first 2 doses.
The 28-day cure rate and parasite clearance observed for Riamet given as a 6-dose regimen over 3 days vs. MAS are summarised in Tables 7 and 8, respectively.
No studies using the proposed dose regimen have been conducted in nonimmune travellers. However, two studies using the 4-dose regimen in travellers returning to Europe demonstrate the safety and efficacy of Riamet in this population. In addition, general results demonstrate that the 6-dose regimen is as safe as and more effective than the 4-dose regimen, thereby supporting the use of the 6-dose regimen in nonimmune patients. Efficacy and safety of Riamet for use as a "stand by" treatment have not been assessed.

5.2 Pharmacokinetic Properties

Pharmacokinetic characterisation of Riamet and Riamet Dispersible tablets are limited by the lack of an intravenous formulation, and the very high inter- and intrasubject variability of artemether and lumefantrine plasma concentrations and derived pharmacokinetic parameters (AUC, C_max).
Absorption. Artemether is absorbed fairly rapidly, with peak plasma concentrations reached about 2 hours after dosing. Absorption of lumefantrine, a highly lipophilic compound, starts after a lag-time of up to 2 hours, with peak plasma concentration about 6-8 hours after dosing.
Food enhances the absorption of both artemether and lumefantrine. In healthy volunteers the relative bioavailability of artemether was increased more than two-fold, and that of lumefantrine sixteen-fold compared with fasted conditions, when Riamet was taken after a high-fat meal. Food has also been shown to increase the absorption of lumefantrine in patients with malaria, although to a lesser extent (approximately two-fold), probably due to the lower fat content of the food ingested by acutely ill patients. The food interaction data indicate that absorption of lumefantrine under fasted conditions is very poor (assuming 100% absorption after a high-fat meal, the amount absorbed under fasted conditions would be < 10% of the dose). Patients should, therefore, be encouraged to take the medication with a normal diet as soon as food can be tolerated.
Distribution. Artemether and lumefantrine are both highly bound to human serum proteins in vitro (97.9% and 99.9%, respectively). Protein binding to human plasma protein is linear.
Metabolism. Artemether is rapidly and extensively metabolised (substantial first-pass metabolism) both in vitro and in humans. Human liver microsomes metabolise artemether to the biologically active main metabolite, dihydroartemisinin (demethylation), predominantly through the enzyme CYP3A4/5. This metabolite has also been detected in humans in vivo. The artemether/dihydroartemisinin AUC ratio is 1.2 after a single dose and 0.3 after 6 doses given over 3 days. In vivo data indicate that artemisinins have some capacity to induce cytochrome isoenzymes CYP2C19 and CYP3A4 (see Section 4.3 Contraindications; Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Lumefantrine is N-debutylated, mainly by CYP3A4, in human liver microsomes; the N-debutylated metabolite of lumefantrine is active. In vitro, lumefantrine significantly inhibits the activity of CYP2D6 at therapeutic plasma concentrations (see Section 4.3 Contraindications; Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Excretion. Artemether and dihydroartemisinin are rapidly cleared from plasma, with an elimination half-life of about 2 hours. Lumefantrine is eliminated very slowly, with a terminal half-life of 2-3 days in healthy volunteers and 4-6 days in patients with falciparum malaria. Demographic characteristics such as sex and weight appear to have no clinically relevant effects on the pharmacokinetics of Riamet.
In healthy volunteers, neither lumefantrine nor artemether was found in urine after administration of Riamet, and urinary excretion of DHA amounted to less than 0.01% of the artemether dose.
Bioavailability of Riamet tablets and Riamet Dispersible tablets in adults. A randomized, open-label, single-dose, three-period, two-sequence, crossover study (B2104) compared the relative bioavailability of Riamet Dispersible tablet to intact and crushed nondispersible Riamet tablets for oral suspension in healthy adult volunteers. Results showed that the exposure to lumefantrine, artemether, and dihydroartemisinin was similar between Riamet Dispersible and Riamet tablet crushed. Bioequivalence of the two formulations was shown for the AUCs of all three compounds and for C_max of lumefantrine and dihydroartemisinin. Results also showed that the exposure to lumefantrine was similar between Riamet Dispersible and Riamet tablet intact, and bioequivalence between the two formulations was shown for lumefantrine AUC and C_max. Of note, the exposure (AUC, C_max) to artemether and dihydroartemisinin were significantly lower (by 20-35%) following the administration of Riamet Dispersible tablets as compared to intact Riamet tablets.
Pharmacokinetics in special patient populations. Paediatrics. Systemic exposure to artemether, DHA, and lumefantrine when dosed on a mg/kg body weight basis in paediatric malaria patients (≥ 5 to < 35 kg body weight), is comparable to that of the recommended dosing regimen in adult malaria patients.
Elderly patients. No specific pharmacokinetic studies have been performed in elderly patients. However, there is no information suggesting that the dosage in patients over 65 years of age should be different than in younger adults (see Section 4.4 Special Warnings and Precautions for Use; Section 4.2 Dose and Method of Administration).
Renal impairment. No specific pharmacokinetic studies have been performed in patients with renal impairment. Based on the pharmacokinetic data in healthy subjects showing no or insignificant renal excretion of lumefantrine, artemether and DHA, no dose adjustment for the use of Riamet and Riamet Dispersible in patients with renal impairment is advised (see Section 4.4 Special Warnings and Precautions for Use; Section 4.2 Dose and Method of Administration).
Hepatic impairment. No specific pharmacokinetic studies have been performed in patients with hepatic impairment. Metabolism is the primary clearance mechanism of both artemether and lumefantrine and may be affected in patients with hepatic impairment. In patients with severe hepatic impairment, a clinically significant increase in exposure to artemether and lumefantrine and/or their metabolites cannot be ruled out. Therefore caution should be exercised in dosing patients with severe hepatic impairment (see Section 4.4 Special Warnings and Precautions for Use; Section 4.2 Dose and Method of Administration).

5.3 Preclinical Safety Data

Genotoxicity. See Section 4.4 Special Warnings and Precautions for Use, Carcinogenicity, mutagenicity and impairment of fertility.
Carcinogenicity. See Section 4.4 Special Warnings and Precautions for Use, Carcinogenicity, mutagenicity and impairment of fertility.

6 Pharmaceutical Particulars

6.1 List of Excipients

Riamet tablets and Riamet Dispersible tablets contain microcrystalline cellulose, croscarmellose sodium, magnesium stearate, hypromellose, colloidal anhydrous silica and polysorbate 80.
Riamet Dispersible tablets also contain sodium saccharin and cherry flavour.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 30°C.
Protect from moisture (dispersible tablets).
Keep out of the reach of children.

6.5 Nature and Contents of Container

Riamet 20 mg/120 mg dispersible tablets contain artemether 20 mg and lumefantrine 120 mg. They are flat, yellow, round, uncoated tablets with bevelled edges; imprinted with "CD" on one side and "NVR" on the other side. Blister packs containing 6*, 12*, 18, 180*, 360*, 540* dispersible tablets.
Riamet tablets (20 mg/120 mg) contain artemether 20 mg and lumefantrine 120 mg. They are pale yellow, flat, round, uncoated tablets with bevelled edges; marked with N/C and a score line on one side and CG on the other. Blister packs containing 16*, 24, or 400* tablets.
*Not all presentations may be available.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

Chemical structure. Active ingredient: artemether. Chemical name: (3R, 5aS, 6R, 8aS, 9R, 10S, 12R, 12aR)- decahydro-10-methoxy- 3,6,9-trimethyl- 3,12-epoxy-12H-pyrano [4,3-j]-1,2-benzodioxepin.
Molecular weight: 298.38.
Molecular formula: C₁₆H₂₆O₅.
Active ingredient: lumefantrine. Chemical name: (1RS)-2-dibutylamino- 1-{2,7-dichloro-9-[(Z)4-chlorobenzylidene]- 9H-fluoren-4-yl}-ethanol.
Molecular weight: 528.95.
Molecular formula: C₃₀H₃₂Cl₃NO.
Chemical structure:

CAS number. Artemether: 71963-77-4.
Lumefrantrine: 82186-77-4.
Pharmacotherapeutic group. Antimalarials, artemisinins and derivatives.
ATC code. P01BE52.

7 Medicine Schedule (Poisons Standard)

Schedule 4 - Prescription Only Medicine.

Date of Revision

24 June 2020

Summary Table of Changes