Antimalarial Drugs MCQs

Ans. is `d' i.e., 300 mg OD/week Drug Dose for chemoprophylaxis Chloroquine 300 mg (3 tablets of 100 mg or 2 tablets of 150 mg) once a week or 100 mg/day for 6 day every week Proguanil 400 mg per day (2 tablets of 200 mg) Mefloquine 250 mg once a week Doxycycline 100 mg per day.

Several classes of antimalarial drugs are available. Drugs that eliminate developing or dormant liver forms are called tissue schizonticides; those that act on erythrocytic parasites are blood schizonticides; and those that kill sexual stages and prevent transmission to mosquitoes are Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal. Page no. 915

When not limited by resistance, chloroquine is a highly effective blood schizonticide. It is also moderately effective against gametocytes of P vivax, P ovale, and P malariae but not against those of P falciparum. Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal, MD. Page n

WHO recommends: Artemisinin-based combination therapies for the treatment of uncomplicated falciparum malaria during the second and third trimesters of pregnancy. Intravenous artesunate or quinine for the treatment of severe malaria during the first trimester. And intravenous artesunate for treatment of severe malaria during the second and third trimesters. Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal, MD. Page no. 921

Primaquine is the drug of choice for the eradication of dormant liver forms of P vivax and P ovale and can also be used for chemoprophylaxis against all malarial species. Primaquine is active against hepatic stages of all human malaria parasites. It is the only available agent active against the dormant hypnozoite stages of P vivax and P ovale. Primaquine is also gametocidal against the four human malaria species. Primaquine acts against erythrocytic stage parasites, but this activity is too weak to play an important role. The mechanism of antimalarial action is unknown. Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal, MD. Page no. 924

Terminal Prophylaxis of Vivax and Ovale Malaria Standard chemoprophylaxis does not prevent a relapse of vivax or ovale malaria, because the hypnozoite forms of these parasites are not eradicated by chloroquine or other available blood schizonticide agents. To markedly diminish the likelihood of relapse, some authorities advocate the use of primaquine after the completion of travel to an endemic area. Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal, MD. Page no. 924

The long-term administration of high doses of chloroquine for rheumatologic diseases can result in irreversible ototoxicity, retinopathy, myopathy, and peripheral neuropathy. These abnormalities are rarely if ever seen with standard-dose weekly chemoprophylaxis, even when given for prolonged periods. Large intramuscular injections or rapid intravenous infusions of chloroquine hydrochloride can result in severe hypotension and respiratory and cardiac arrest. Parenteral administration of chloroquine is best avoided, but if other drugs are not available for parenteral use, it should be infused slowly. Reference: LANG' Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 52- Antiprotozoal Agents by Dr. Philip J. Rosenthal. Page no. 920

Oral absorption of MQ is good but peak concentrations are reached 5-15 hours. It is highly plasma protein bound and Concentrated in many organs including liver, lung and intestines. Extensive metabolism occurs in the liver and it is primarily secreted in bile. Considerable enterohepatic circulation of MQ and its tissue binding accounts for the long t½ which is 2-3 weeks. Option A: High plasma protein binding means the drug would remain in the intravascular compartment and hence won’t undergo glomerular filtration Option B: High plasma protein binding means the drug would remain in the intravascular compartment and hence will have a low Volume of distribution Option C: High plasma protein binding increases the duration of action Option D: High plasma protein binding would lead to more drug interactions as many drugs may bind to a similar protein.