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/
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.
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
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
少量或没有给予的药物或二氢青蒿素可以在尿液中回收。/二氢青蒿素/
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/
来源:Hazardous Substances Data Bank (HSDB)
文献信息
HIGH DOSE ORAL PHARMACEUTICAL COMPOSITIONS OF ARTEMETHER AND LUMEFANTRINE
申请人：Ranbaxy Laboratories Limited
公开号：EP2034986A2
公开（公告）日：2009-03-18
[EN] HIGH DOSE ORAL PHARMACEUTICAL COMPOSITIONS OF ARTEMETHER AND LUMEFANTRINE<br/>[FR] COMPOSITIONS PHARMACEUTIQUES POUR L'ADMINISTRATION ORALE À DES DOSES ÉLÉVÉES D'ARTEMÉTHER ET DE LUMÉFANTRINE
申请人：RANBAXY LAB LTD
公开号：WO2008001294A2
公开（公告）日：2008-01-03
[EN] The present invention relates to high dose oral pharmaceutical compositions of artemether and lumefantrine, and process for preparation thereof. The compositions comprise of artemether and lumefantrine comprising artemether in an amount of from about 40 mg to about 80 mg, lumefantrine in an amount of from about 240 mg to about 480 mg. The compositions are useful for treatment of uncomplicated infections with Plasmodium falciparum, including strains from multi-drug-resistant areas. [FR] La présente invention concerne des compositions pharmaceutiques pour l'administration orale à des doses élevées d'arteméther et de luméfantrine, ainsi qu'un procédé permettant de les préparer. Les compositions comprennent de l'arteméther et de la luméfantrine, comprenant de l'arteméther dans une quantité d'environ 40 mg à environ 80 mg, de la luméfantrine dans une quantité d'environ 240 mg à environ 480 mg. Les compositions sont utiles pour le traitement d'infections non compliquées provoquées par Plasmodium falciparum, comprenant des souches provenant de zones résistantes à de multiples médicaments.
