Artemether

298.37

298.37

1806241-263-5

DTXSID7040651

Crystals

P - Antiparasitic products, insecticides and repellents

2932999099

46.2

3.53

off-white to light brown

1.2±0.1 g/cm3

86-88 °C

358ºC

140.5±27.8 °C

1.518

DMSO: ≥20mg/mL

room temp

4X10-5 mm Hg at 25 °C (est)

Oral-Mouse LD50: 1000 mg/kg; Subcutaneous-mouse LD50: 390 mg/kg

Flammable; burning produces irritating fumes

D19.5 +171° (c = 2.59 in CHCl3)

Henry's Law constant = 1.9X10-9 atm-cu m/mol at 25 °C (est)

Hydroxyl radical reaction rate constant = 4X10-11 cu cm/molec-sec at 25 °C (est)

NONH for all modes of transport

3

22

24/25

KD4165000

Xn

Ventilated, low temperature and dry

P301 + P312 + P330

H302

|Warning|H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P301+P312, P330, and P501|Aggregated GHS information provided by 41 companies from 3 notifications to the ECHA C&L Inventory.

moderately toxic

Animal studies on acute toxicity show that the LD50 of Artemether in mice is a single i.g. administration of 895mg/kg and a single i.m. injection of 296mg/kg dose; in rats, the LD50 is a single i.m. injection of 597mg/kg dose.

The aim of this study was to evaluate the effect of grapefruit juice on the decreasing bioavailability over time of artemether. In a randomized, two-phase crossover study, eight healthy male subjects took 100 mg oral artemether with 350 mL water or with 350 mL double-strength fresh frozen grapefruit juice once daily for 5 days. On day 1 and day 5, 17 blood samples were collected over a period of 8 hours. The mean peak artemether plasma concentration (Cmax) and the mean area under the concentration-time curve (AUC) after the last dose at day 5 were about one third compared with day 1, without a change in the elimination half-life after intake with water (P = .006 for Cmax; P = .005 for AUC) and with grapefruit juice (P < .001 for Cmax and AUC). Grapefruit juice increased Cmax (P = .021) and AUC (P < .001) twofold on day 1 (P = .021) and day 5 (P = .05 for Cmax; P = .004 for AUC). Dihydroartemisinin, the active metabolite, showed a twofold increase in Cmax (P = .006) and AUC (P = .001) with grapefruit juice, without time-dependent changes of pharmacokinetic parameters. Grapefruit juice significantly increased the oral bioavailability of artemether but did not prevent the time-dependent reduction in bioavailability. It suggests that CYP3A4 in the gut wall is one of the metabolizing enzymes of artemether but seems to not be involved in the autoinduction process.|There has been some concern that antipyretics might attenuate the host defense against malaria, as their use is associated with delayed parasite clearance. However, this appears to result from delaying cytoadherence, which is likely to be beneficial. There is no reason to withhold antipyretics in malaria. ...Paracetamol (acetaminophen) and ibuprofen are the preferred options for reducing fever.

Artemether and lumefantrine are both highly bound to human serum proteins in vitro (95.4% and 99.7%, respectively). Dihydroartemisinin is also bound to human serum proteins (47% to 76%).

According to an index that ranks medicinal chemicals persistence, bioaccumulation, and toxicity (PBT) potential, artemether has a PBT of 7 on an index ranging from 0 (the lowest PBT) to 9 (the highest potential PBT)(1).

While data specific to artemether were not located(SRC, 2006), the literature suggests that some pharmaceutically active compounds originating from human and veterinary therapy are not eliminated completely in municipal sewage treatment plants and are therefore discharged into receiving waters(1). Wastewater treatment processes often were not designed to remove them from the effluent(2). Selected organic waste compounds may be degrading to new and more persistent compounds that may be released instead of or in addition to the parent compound(2). Studies have indicated that several polar pharmaceutically active compounds can leach through subsoils(1).

Artemether and lumefantrine combination therapy is indicated for the treatment of acute uncomplicated malaria caused by Plasmodium falciparum, including malaria acquired in chloroquine-resistant areas. May also be used to treat uncomplicated malaria when the Plasmodium species has not been identified. Indicated for use in adults and children greater than 5 kg.|FDA Label|Treatment of Plasmodium falciparum malaria

MESH Heading: Antimalarial, antifungal, antiprotozoal, coccidiostats, schistosomicides|Therap Cat: Antimalarial|To counter the threat of resistance of P. falciparum to monotherapies, and to improve treatment outcome, combinations of antimalarials are now recommended by WHO for the treatment of falciparum malaria. ...The following ACTs are currently recommended: artemether-lumefantrine.|Artemether-lumefantrine: This is currently available as co-formulated tablets .... The total recommended treatment is a 6-dose regimen of artemether-lumefantrine twice a day for 3 days. An advantage of this combination is that lumefantrine is not available as a monotherapy and has never been used by itself for the treatment of malaria. Recent evidence indicates that the therapeutic response and safety profile in young children of less than 10 kg is similar to that in older children, and artemether-lumefantrine is now recommended for patients 5 kg. Lumefantrine absorption is enhanced by co-administration with fat. Low blood levels, with resultant treatment failure, could potentially result from inadequate fat intake, and so it is essential that patients or carers are informed of the need to take this ACT /antimalarial combination therapy/ with milk or fat-containing food -- particularly on the second and third days of treatment.|For more Therapeutic Uses (Complete) data for ARTEMETHER (11 total), please visit the HSDB record page.

Transient first-degree heart block, dose-related reversible decreases in reticulocyte and neutrophil counts, and temporary elevations of serum aspartate aminotransferase activity have been reported ... Brief episodes of drug-induced fever in human volunteers were noted in some studies ... /Artemisinin drugs/|Because high doses of artemisinin drugs can produce neurotoxicity, prolongation of the QT interval, bone marrow depression, and fetal reabsorption in experimental animals, the possibility of long-term toxicity in human beings exists. /Artemisinin drugs/|Some patients cannot tolerate oral treatment, and will require parenteral or rectal administration for 1-2 days until they can swallow and retain oral medication reliably. Although such patients may not show signs of severity, they should receive the same antimalarial dose regimens as for severe malaria.|Some patients may have no signs of severity but on examination of the blood film are found to have very high parasitaemia. The risks associated with high parasitaemia vary depending on the age of the patient and on transmission intensity. Thus cut-off values and definitions of hyperparasitaemia also vary. Patients with high parasitaemias are at an increased risk of treatment failure and of developing severe malaria, and therefore have an increased risk of dying. These patients can be treated with the oral Antimalarial Combination Therapies (ACTs) recommended for uncomplicated malaria. However, they require close monitoring to ensure that the drugs are retained and that signs of severity do not develop, and they may require a longer course of treatment to ensure cure.|For more Drug Warnings (Complete) data for ARTEMETHER (18 total), please visit the HSDB record page.

With the exception of artemether-lumefantrine, the partner medicines of all other Antimalarial Combination Therapies (ACTs) have been previously used as monotherapies, and still continue to be available as such in many countries. Their continued use as monotherapies can potentially compromise the value of Antimalarial Combination Therapies (ACTs) by selecting for drug resistance. The withdrawal of artemisinins and other monotherapies is recommended.

In the body, artemether is metabolized into the active metabolite metabolite dihydroartemisinin. The drug works against the erythrocytic stages of P. falciparum by inhibiting nucleic acid and protein synthesis. Artemether is administered in combination with lumefantrine for improved efficacy. Artemether has a rapid onset of action and is rapidly cleared from the body. It is thought that artemether provides rapid symptomatic relief by reducing the number of malarial parasites. Lumefantrine has a much longer half life and is believed to clear residual parasites.

Agents used in the treatment of malaria. They are usually classified on the basis of their action against plasmodia at different stages in their life cycle in the human. (From AMA, Drug Evaluations Annual, 1992, p1585) (See all compounds classified as Antimalarials.)

Food increases absorption.|Little or none of the administered drugs or dihydroartemisinin is recovered in urine. /Dihydroartemisinin/|After intramuscular administration pharmacokinetics indicated peak plasma levels of artemether (AM) at 2 to 4 hours post-dose, slow elimination and a tendency to accumulate after repeated administration. Only low levels of the major metabolite, dihydroartemisinin (DHA), were found. AM levels in the cerebrospinal fluid (CSF) were < 10% of plasma levels. After oral administration AM concentrations were considerably lower than after i.m. administration. The concentration of DHA was high on day 1 but almost nil on day 7 indicating its fast inactivation in dogs. Two hours after the 8th oral administration neither AM nor DHA was detected in CSF which may explain the absence of neurotoxicity in dogs after oral administration of AM.|The pharmacokinetics of intramuscular artemether and its major plasma metabolite-dihydroartemisinin, were investigated in patients with severe manifestations of falciparum malaria. Six severe falciparum malaria patients with acute renal failure (ARF) and 11 without ARF were recruited into the study. They were treated with intramuscular artemether at a loading dose of 160 mg, followed by daily doses of 80 mg for another 6 days (total dose 640 mg). Patients with and without ARF showed a good initial response to treatment; the parasite and fever clearance times were 66 (30 to 164) and 76 (36 to 140) hr (median (range)), respectively. None had reappearance of parasitaemia in their peripheral blood smear within 7 days of initiation of treatment. In comatose patients, the time to recovery of consciousness was 51.6 (22 to 144) hr. Artemether was detected in plasma as early as 1hr after a 160 mg dose, and declined to undetectable levels within 24 hr in most cases. Patients with ARF had significantly higher Cmax (2.38 (1.89 to 3.95) vs 1.56 (1.05 to 3.38) ng/mL/mg dose), and lower Vz/F (5.45 (3.2 to 6.9) vs 8.6 (4.2 to 12.3) L/kg) and CL/F (7.4 (5.4 to 13.8) vs 19.1 (8.5 to 25.1) mL/min/kg) when compared to those without ARF. In addition, t1/2z, was significantly longer in ARF patients (7.0 (5.5 to 10.0) vs 5.7 (4.2 to 6.6) hr). The parmacokinetics of dihydroartemisinin in the two groups were comparable. ARF significantly modified the pharmacokinetics of intramuscular artemether. The changes could be contributed to either improved absorption/bioavailability, a reduction of systemic clearance, or a change in plasma protein binding of the drug.|Dihydroartemisinin is rapidly absorbed following oral administration, reaching peak levels after around 2.5 hr. Absorption via the rectal route is somewhat slower, with peak levels occurring around 4 hr after administration. Plasma protein binding is around 55%. Elimination half-life is approximately 45 min via intestinal and hepatic glucuronidation. /Dihydroartemisinin/|For more Absorption, Distribution and Excretion (Complete) data for ARTEMETHER (6 total), please visit the HSDB record page.

Rapidly metablized to its active metabolite, dihydroartemisinin.|Artemether ... /is/ converted to dihydroartemisinin ... The antimalarial effect of artemisinin compounds results primarily from dihydroartemisinin ...|Artemisinin is completely and rapidly absorbed after oral administration in rats. However, a very low plasma level was obtained even after a dose of 300 mg/kg. Liver was found to be the chief site of inactivation. When artemisinin was given i.m., significant and more persistent plasma levels were detected. Artemisinin was shown to pass the blood-brain and blood-placenta barriers after i.v. injection. Very little unchanged artemisinin was found in the urine or feces in 48 hours regardless of the route of administration. Metabolites identified after administration to humans include deoxyartemisinin, deoxydihydroartemisinin, and 9,10-dihydroxydeoxyartemisinin. /Artemisinin/

Artemether, 1.6 +/- 0.7 and 2.2 +/- 1.9 hr; Dihydroartemisinin, 1.6 +/- 0.6 and 2.2 +/- 1.5 hr|Artemether ... /is/ converted to dihydroartemisinin ... which rapidly disappears from plasma with a half-life of about 45 min.

Involves an interaction with ferriprotoporphyrin IX (“heme”), or ferrous ions, in the acidic parasite food vacuole, which results in the generation of cytotoxic radical species. The generally accepted mechanism of action of peroxide antimalarials involves interaction of the peroxide-containing drug with heme, a hemoglobin degradation byproduct, derived from proteolysis of hemoglobin. This interaction is believed to result in the formation of a range of potentially toxic oxygen and carbon-centered radicals.|Artemether (AM) is an antimalarial drug derived from artemisinin (Qinghaosu), an extract of the herb Artemisia annua L., sweet wormwood. Its antiparasitic effect is that of a schizontocide and is explained by rapid uptake by parasitized erythrocytes and interaction with a component of hemoglobin degradation resulting in formation of free radicals. It has been shown to exhibit a high clinical cure rate.|Two theories have been put forward for the mode of antimalarial action of the artemisinin antimalarials, in accodance with the known properties of peroxides with medicinal activity. The first assumes that the artemisinins must be activated by contact with either reduced haem (ferrous haem, Fe(ll)PPIX) or non-haem ferrous iron (exogenous iron), causing cleavage of the peroxide to generate oxygen-centered radicals (alkoxy radicals') which are then presumed to be converted into carbon-centered radicals by transfer of proximate hydrogen atoms from the periphery of the peroxide molecule. These carbon-centered radicals are then thought to alkylate sensitive, yet unspecified, biomolecules in the parasite. A second theory argues for a process in which the intact artemisinin binds to a site within a vital protein in the parasite. The act of binding causes the peroxide to be converted to hydroperoxide or similar open peroxide, which in accordance with known properties of such compounds, generates one or more active chemical entities, either oxidizing agents or oxygen transfer agents per se, or oxygen-centered free radicals. This would be associated with the binding process. In such a way, the artemisinins might act as (irreversibile) inhibitors. Iron may, or may not, be associated with the activation process. No specific biological target in the parasite has yet been identified in support of this theory, but it may be membrane-bound proteins.

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

/CASE REPORTS/ A total of 83 pregnant women with Plasmodium falciparum malaria, administered artesunate or artemether, often followed by quinine or mefloquine, were followed weekly until delivery. Overall 73 pregnancies (88%) resulted in live births, 3 (4%) in abortions, and 2 (3%) in still births. There were no congenital abnormalities and the 46 children followed for more than a year all developed normally|/EPIDEMIOLOGY STUDIES/ Cardiotoxicity has become a major concern during treatment with antimalarial drugs. Lengthening of the QTc and severe cardiac arrhythmia have been observed ... The purpose of this prospective study was to evaluate whether antimalarial agents alter dispersion of the QTc and ventricular repolarization dynamicity. Sixty patients with uncomplicated falciparum malaria were randomly allocated in four groups of 15 patients and treated with quinine, mefloquine, artemether, or halofantrine at recommended doses. Patients in treatment groups were compared with a group including 15 healthy controls with no history of malaria and/or febrile illness within the last month. QTc dispersion was measured on surface electrocardiograms. Repolarization dynamicity was analyzed from Holter recordings, which allow automatic beat-to-beat measurement of QT and RR intervals. Plasma drug concentration was determined by reversed-phase high-performance liquid chromatography. No change in QTc dispersion was observed after treatment with quinine, mefloquine, or artemether. ... Mefloquine and artemether did not alter ventricular repolarization. Quinine induced a significant decrease in QT/RR slope of the same order of magnitude as those previously observed with quinidine. ...|/EPIDEMIOLOGY STUDIES/ A meta-analysis using individual patient data from randomized controlled trials comparing artemether and quinine in severe falciparum malaria /was conducted/. Eleven trials were identified, of which 8 were clearly randomized. Original individual patient data on 1919 patients were obtained from 7 trials, representing 85% of the patients in the original 11 studies. Overall there were 136 deaths among the 961 patients treated with artemether, compared with 164 in the 958 treated with quinine [14% vs 17%, odds ratio (95% confidence interval) 0.8 (0.62 to 1.02), P = 0.08]. There were no differences between the 2 treatment groups in coma recovery or fever clearance times, or the development of neurological sequelae. However, the combined 'adverse outcome' of either death or neurological sequelae was significantly less common in the artemether group [odds ratio (95% CI) 0.77 (0.62 to 0.96), P = 0.02], and treatment with artemether was associated with significantly faster parasite clearance [hazard ratio (95% CI) 0.62 (0.56 to 0.69), P < 0.001]. In subgroup analyses artemether was associated with a significantly lower mortality than quinine in adults with multisystem failure. In the treatment of severe falciparum malaria artemether is at least as effective as quinine in terms of mortality and superior to quinine in terms of overall serious adverse events. There was no evidence of clinical neurotoxicity or any other major side-effects associated with its use.|/EPIDEMIOLOGY STUDIES/ A recent report from Mozambique described a small but significant and irreversible hearing loss in patients exposed to artemether-lumefantrine. To explore this issue, we conducted a case-control study using tympanometry, audiometry and auditory brain-stem responses. We assessed 68 subjects who had been treated with artemether-lumefantrine within the previous five years and 68 age- and sex-matched controls living in the malarious region along the Thailand-Myanmar border. There were no differences in the test results between cases and controls. There was no neurophysiologic evidence of auditory brainstem toxicity that could be attributed to artemether-lumefantrine in this study population.

alpha Artemether

Artemether and artemotil are dispensed dissolved in oil (groundnut, sesame seed) and given by i.m. injection into the anterior thigh.

Analyte: artemether; matrix: blood (plasma); procedure: high-performance liquid chromatography with electrochemical detection

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