MEFLOQUINE HYDROCHLORIDE

MEFLOQUINE HYDROCHLORIDE
(me-flo'quine)
Lariam
Classifications: antimalarial;
Therapeutic: antimalarial
Prototype: Chloroquine
Pregnancy Category: C

Availability

250 mg tablets

Action

Antimalarial agent, structurally related to quinine.

Therapeutic Effect

Effective against all types of malaria, including chloroquine-resistant malaria.

Uses

Treatment of mild to moderate acute malarial infections, prevention of chloroquine-resistant malaria caused by Plasmodium falciparum and P. vivax.

Contraindications

Hypersensitivity to mefloquine or a related compound; with a calcium channel blocking agent, severe heart arrhythmias, history of QT_c prolongation; aggressive behavior; active depression, or history of depression, suicidal ideation; generalized anxiety disorder, psychosis, schizophrenia, or other major psychiatric disorders; seizure disorders; pregnancy (category C); lactation.

Cautious Use

Persons piloting aircraft or operating heavy machinery.

Route & Dosage

Note: FDA has NOT approved use of mefloquine in children, and the U.S. Public Health Service does NOT recommend its use in children <15 kg or in pregnant women

Treatment of Malaria
Adult: PO 1250 mg (5 tablets) as single oral dose taken with at least 8 oz of water
Child: PO 20–30 mg/kg as single dose

Prophylaxis for Malaria
Adult: PO 250 mg once/wk x 4 wk (beginning 1 wk before travel), then 250 mg every other wk for duration of exposure and for 2 doses after leaving endemic area
Child: PO 15–19 kg, 1/4 tablet; 20–30 kg, ? tablet; 31–45 kg, ? tablet

Administration

Oral

Give with food and at least 8 oz water.
Do not give concurrently with quinine or quinidine; wait at least 12 h beyond last dose of either drug before administering mefloquine.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Arthralgia, chills, fatigue, fever. CNS: Dizziness, nightmares, visual disturbances, headache, syncope, confusion, psychosis, aggression, suicide ideation (rare). CV: Bradycardia, ECG changes (including QT_c prolongation), first-degree AV block. GI: Nausea, vomiting, abdominal pain, anorexia, diarrhea. Skin: Rash, itching.

Diagnostic Test Interference

Transient increase in liver transaminases.

Interactions

Drug: Mefloquine can prolong cardiac conduction in patients taking beta blockers, calcium channel blockers, and possibly digoxin. Quinine may decrease plasma mefloquine concentrations. Mefloquine may decrease valproic acid serum concentrations by increasing its hepatic metabolism. Administration with chloroquine may increase risk of seizures. Increased risk of cardiac arrest and seizures with quinidine.

Pharmacokinetics

Absorption: 85% absorbed, concentrates in red blood cells. Onset: 59 and 28 h for parasite and fever clearance times in patients with P. vivax infections, respectively; 166 and 93 h in patients with P. malariae infections. Distribution: Concentrated in red blood cells due to high-affinity binding to red blood cell membranes; 98% protein bound; distributed minimally into breast milk. Metabolism: In liver. Elimination: Primarily in bile and feces. Half-Life: 10–21 d (shorter in patients with acute malaria).

Nursing Implications

Assessment & Drug Effects

Monitor carefully during prophylactic use for development of unexplained anxiety, depression, restlessness, or confusion; such manifestations may indicate a need to discontinue the drug.
Evaluate cardiac and liver functions periodically with prolonged use.
Lab tests: Monitor periodically CBC with differential during prolonged use.
Monitor blood levels of anticonvulsants with concomitant therapy closely.

Patient & Family Education

Take drug on the same day each week when used for malaria prophylaxis.
Do not perform potentially hazardous activities until response to drug is known.
Report any of the following immediately: Fever, sore throat, muscle aches, visual problems, anxiety, confusion, mental depression, hallucinations.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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