Antiprotozoal tx

Question 1

Albendazole: MOA and adverse rxns

Answer 1

Used for nematodes

MOA: inhibits microtubule synthesis in nematodes, irreversibly impairs glucose uptake –> parasite immobilized or dies slowly; also has larvicidal and ovicidal effects

Adverse rxn: migration of roundworms through mouth and nose, leukopenia, alopecia, increased transaminases
Drug interactions: dexamethasone and praziquantel increase levels

Question 2

Praziquantel: MOA and adverse rxns

Answer 2

MOA: loss of intracellular calcium results in paralysis and dislodgement of worms

Adverse: fever, sweating, esoinophilia; structurally similar to benzos
Drug interactions: dexamethasone, carbamazepines, phenobarbital, phenytoin all cause decreased drug levels; cimetidine, ketoconazole, erythromycin all increase levels

Question 3

Pyrantel pamoate: MOA and adverse rxns

Answer 3

used for pinworms and roundworms
MOA: depolarizing neuromuscular blocker, spastic paralysis of parasite, inhibits cholinesterase

Adverse rxn: rash, transient AST elevations
Drug interactions: piperazine -
avoid concomitant use; increases theophylline levels in peds

Question 4

luminal vs. extraluminal tx

Answer 4

luminal = never absorbed systemically
extraluminal = absorbed systemically

Question 5

Drugs used for amebiasis

Answer 5

Luminal: Iodoquinol, Paromomycin
Extraluminal: Metronidazole, Pentamidine

Question 6

Metronidazole: Used for, adverse rxn, drug/food interactions

Answer 6

Used for: tx of amebiasis (extraluminal)

Adverse rxn: xerostomia, METALLIC TASTE, furry tongue, change in taste sensation, DARK URINE, SEIZURES, NEUROPATHY, pancreatitis, DISULFIRAM TYPE REACTION WITH ALCOHOL (flushing, HA, N/V, sweating, tachycardia)

Drug interactions: phenytoin and phenobarbital decrease levels, alcohol or disulfiram contraindicated, increases warfarin effects, increases lithium levels, cimetidine increases levels

Food interaction: antibiotics impaired

Question 7

Malaria cause and sxs

Answer 7

Plasmodium!

Initial sxs: chills, fever, HA, malaise, fatigue, nausea, muscle pains, and mild diarrhea

Severe sxs: delirium, impaired consciousness, generalized convulsions, followed by coma and death

Question 8

Most deadly cause of malaria

Answer 8

P. falciparum

Question 9

malaria tx: DOC (all plasmodium except chloriquine resistant P. falciparum and P. vivax)

Answer 9

chloroquine phosphate

Question 10

Malaria tx: DOC ALL PLASMODIUM

Answer 10

quinidine gluconate or quinine dihydrochloride

Question 11

Malaria tx: prevention of relapses for P. vivax and P. ovale

Answer 11

primaquine phosphate

Question 12

Malaria tx: DOC chloroquine resistant P. falciparum

Answer 12

Quinine sulfate + doxycycline, tetracycline, pyrimethamin-sulfadoxine, or clindamycin

atovaquone/proguanil (malarone)

Question 13

Malaria tx: DOC chloroquine resistant P. vivax

Answer 13

quinine sulfate + doxycycline or mefloquine

Question 14

Prophylaxis of malaria: chloroquine sensitive areas

Answer 14

chloroquine phosphate

Question 15

prophylaxsis of malaria: chloroquine resistant areas

Answer 15

mefloquine or doxycycline or atovaquone/proguanil (malarone)

Question 16

Chloroquine contraindications and adverse reactions

Answer 16

Contra: retinal or visual field changes; patients with psoriasis and porphyria

Adverse: GI, fatigue, hypotension, EKG changes, blood dyscrasias, ocular toxicity, blurred vision, skin reactions, peripheral neuropathy, psychosis and seizures

Question 17

Quinine and quinidine: adverse reactions

Answer 17

Tinnitus, nausea, visual disturbances, headache, dizziness, flushing - cinchonism, Blood dyscrasias, Hepatitis
Cardiovascular toxicity, Severe hypotension with IV administration, Hypoglycemia,
NO GI SXS

Use in pregnancy can cause ototoxicity and deafness in neonates

Question 18

Mefloquine: contraindications and adverse reactions

Answer 18

Contra: recent h/o depression, generalized anxiety disorder, psychosis, or schizophrenia or other major psychiatric disorders

Adverse: Toxic psychosis
Seizures, Prolonged QT syndrome, Dysrhythmias, GI, Dizziness, Weakness, Nightmares, Dysphoria, Visual disturbances, Disturbed sense of balance, Post-malaria neurologic syndrome

Question 19

Primaquine: why its unique and adverse rxn

Answer 19

Only available agent active against dormant stages of P. vivax and P. ovale

Adverse: GI, Hemolytic anemia in G-6-PD deficiency, Methemoglobinemia, Arrhythmias, pruritus, leukopenia, agranulocytosis, leukocytosis, interference with visual accommodation

Question 20

Pyrimethamine: adverse rxn

Answer 20

GI, Megaloblastic anemia, leukopenia, thrombocytopenia, agranulocytosis,

***Stevens-Johnson syndrome

Question 21

Proguanil: adverse rxn

Answer 21

Aphthous ulcerations, Hair loss, Scaling of palms and soles, Urticaria, Hematuria (with large doses), GI, Thrombocytopenia

Question 22

Atovaquone: adverse rxn

Answer 22

Rash, Headache, Fever, Insomnia, Asthenia, Pruritus, Anemia (rare), Neutropenia (rare), Hyponatremia, Elevated hepatic enzymes