Atovaquone and Proguanil Hydrochloride Pediatric
Brand names: Atovaquone and Proguanil Hydrochloride Pediatric, Atovaquone and Proguanil Hydrochloride
Warnings
5 WARNINGS AND PRECAUTIONS • Atovaquone absorption may be reduced in patients with diarrhea or vomiting. If used in patients who are vomiting, parasitemia should be closely monitored and the use of an antiemetic considered. In patients with severe or persistent diarrhea or vomiting, alternative antimalarial therapy may be required. ( 5.1 ) • In mixed P. falciparum and Plasmodium vivax infection, P. vivax relapse occurred commonly when patients were treated with atovaquone and proguanil hydrochloride alone. ( 5.2 ) • In the event of recrudescent P. falciparum infections after treatment or prophylaxis failure, patients should be treated with a different blood schizonticide. ( 5.2 ) • Elevated liver laboratory tests and cases of hepatitis and hepatic failure requiring liver transplantation have been reported with prophylactic use. ( 5.3 ) • Severe Cutaneous Adverse Reactions (SCARs): Cases of SCARs such as Stevens-Johnson syndrome (SJS) have been reported. SCARs can be life-threatening or fatal. If symptoms or signs of SCARs develop, discontinue atovaquone and proguanil hydrochloride immediately and institute appropriate therapy. ( 5.4 ) • Atovaquone and proguanil hydrochloride has not been evaluated for the treatment of cerebral malaria or other severe manifestations of complicated malaria. Patients with severe malaria are not candidates for oral therapy. ( 5.5 ) 5.1 Vomiting and Diarrhea Absorption of atovaquone may be reduced in patients with diarrhea or vomiting. If atovaquone and proguanil hydrochloride is used in patients who are vomiting, parasitemia should be closely monitored and the use of an antiemetic considered. [See Dosage and Administration ( 2 ).] Vomiting occurred in up to 19% of pediatric patients given treatment doses of atovaquone and proguanil hydrochloride. In the controlled clinical trials, 15.3% of adults received an antiemetic when they received atovaquone/proguanil and 98.3% of these patients were successfully treated. In patients with severe or persistent diarrhea or vomiting, alternative antimalarial therapy may be required. 5.2 Relapse of Infection In mixed P. falciparum and Plasmodium vivax infections, P. vivax parasite relapse occurred commonly when patients were treated with atovaquone and proguanil hydrochloride alone. In the event of recrudescent P. falciparum infections after treatment with atovaquone and proguanil hydrochloride or failure of chemoprophylaxis with atovaquone and proguanil hydrochloride, patients should be treated with a different blood schizonticide. 5.3 Hepatotoxicity Elevated liver laboratory tests and cases of hepatitis and hepatic failure requiring liver transplantation have been reported with prophylactic use of atovaquone and proguanil hydrochloride. 5.4 Severe Cutaneous Adverse Reactions Cases of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), drug reaction with eosinophilia and systemic symptoms (DRESS), and erythema multiforme (EM) have been reported in patients treated with atovaquone and proguanil hydrochloride [see Adverse Reactions ( 6.2 )] . SCARs can be life-threatening or fatal. If symptoms or signs of SCARs develop, discontinue atovaquone and proguanil hydrochloride immediately and institute appropriate therapy. Patients who have developed SCARs with the use of atovaquone and proguanil hydrochloride must not receive atovaquone and proguanil hydrochloride [see Contraindications ( 4 )]. 5.5 Severe or Complicated Malaria Atovaquone and proguanil hydrochloride has not been evaluated for the treatment of cerebral malaria or other severe manifestations of complicated malaria, including hyperparasitemia, pulmonary edema, or renal failure. Patients with severe malaria are not candidates for oral therapy.
Contraindications
Overdose
10 OVERDOSAGE There is no information on overdoses of atovaquone and proguanil hydrochloride substantially higher than the doses recommended for treatment. There is no known antidote for atovaquone, and it is currently unknown if atovaquone is dialyzable. Overdoses up to 31,500 mg of atovaquone have been reported. In one such patient who also took an unspecified dose of dapsone, methemoglobinemia occurred. Rash has also been reported after overdose. Overdoses of proguanil hydrochloride as large as 1,500 mg have been followed by complete recovery, and doses as high as 700 mg twice daily have been taken for over 2 weeks without serious toxicity. Adverse experiences occasionally associated with proguanil hydrochloride doses of 100 to 200 mg/day, such as epigastric discomfort and vomiting, would be likely to occur with overdose. There are also reports of reversible hair loss and scaling of the skin on the palms and/or soles, reversible aphthous ulceration, and hematologic side effects.
Drug interactions
7 DRUG INTERACTIONS • Administration with rifampin or rifabutin is known to reduce atovaquone concentrations; concomitant use with atovaquone and proguanil hydrochloride is not recommended. ( 7.1 ) • Proguanil may potentiate anticoagulant effect of warfarin and other coumarin-based anticoagulants. Caution advised when initiating or withdrawing atovaquone and proguanil hydrochloride in patients on anticoagulants; coagulation tests should be closely monitored. ( 7.2 ) • Tetracycline may reduce atovaquone concentrations; parasitemia should be closely monitored. ( 7.3 ) 7.1 Rifampin/Rifabutin Concomitant administration of rifampin or rifabutin is known to reduce atovaquone concentrations [see Clinical Pharmacology ( 12.3 )] . The concomitant administration of atovaquone and proguanil hydrochloride and rifampin or rifabutin is not recommended. 7.2 Anticoagulants Proguanil may potentiate the anticoagulant effect of warfarin and other coumarin-based anticoagulants. The mechanism of this potential drug interaction has not been established. Caution is advised when initiating or withdrawing malaria prophylaxis or treatment with atovaquone and proguanil hydrochloride in patients on continuous treatment with coumarin-based anticoagulants. When these products are administered concomitantly, coagulation tests should be closely monitored. 7.3 Tetracycline Concomitant treatment with tetracycline has been associated with a reduction in plasma concentrations of atovaquone [see Clinical Pharmacology ( 12.3 )] . Parasitemia should be closely monitored in patients receiving tetracycline. 7.4 Metoclopramide While antiemetics may be indicated for patients receiving atovaquone and proguanil hydrochloride, metoclopramide may reduce the bioavailability of atovaquone and should be used only if other antiemetics are not available [see Clinical Pharmacology ( 12.3 )] . 7.5 Indinavir Concomitant administration of atovaquone and indinavir did not result in any change in the steady-state AUC and C max of indinavir but resulted in a decrease in the C trough of indinavir [see Clinical Pharmacology ( 12.3 )] . Caution should be exercised when prescribing atovaquone with indinavir due to the decrease in trough concentrations of indinavir.
Uses
1 INDICATIONS AND USAGE Atovaquone and proguanil hydrochloride tablets are an antimalarial indicated for: • prophylaxis of Plasmodium falciparum malaria, including in areas where chloroquine resistance has been reported. ( 1.1 ) • treatment of acute, uncomplicated P. falciparum malaria. ( 1.2 ) 1.1 Prevention of Malaria Atovaquone and proguanil hydrochloride tablets are indicated for the prophylaxis of Plasmodium falciparum malaria, including in areas where chloroquine resistance has been reported. 1.2 Treatment of Malaria Atovaquone and proguanil hydrochloride tablets are indicated for the treatment of acute, uncomplicated P. falciparum malaria. Atovaquone and proguanil hydrochloride tablets have been shown to be effective in regions where the drugs chloroquine, halofantrine, mefloquine, and amodiaquine may have unacceptable failure rates, presumably due to drug resistance.