Home Drug Guide Mefloquine Hydrochloride

Drug Guide

Generic Name

Mefloquine Hydrochloride

Brand Names Lariam

Classification

Therapeutic: Antimalarial Agent

Pharmacological: Amino Alcohol Antimalarial

FDA Approved Indications

Prevention and treatment of malaria caused by Plasmodium falciparum, P. vivax, P. malariae, and P. ovale

Mechanism of Action

Mefloquine disrupts the parasite's ability to detoxify heme into non-toxic hemozoin, accumulating toxic heme within the parasite and leading to its death.

Dosage and Administration

Adult: Prevention: 250 mg once weekly starting 2-3 weeks before travel, continuing during travel and for 4 weeks after leaving endemic area. Treatment: 750 mg as a single dose, followed by 250 mg in 6-8 hours and 250 mg after 24 hours.

Pediatric: Dose based on weight, typically 25-50 mg/kg divided over the dosing period.

Geriatric: Use with caution; dose adjustments based on renal and hepatic function.

Renal Impairment: No specific adjustment, but caution advised due to drug accumulation risk.

Hepatic Impairment: Use with caution; extensive hepatic metabolism requires caution in hepatic impairment.

Pharmacokinetics

Absorption: Well absorbed orally, with high bioavailability.

Distribution: Widely distributed; crosses blood-brain barrier and placental barrier.

Metabolism: Primarily hepatic via CYP3A4 enzymes.

Excretion: Excreted mainly in feces, some in urine.

Half Life: approximately 2-4 weeks, which is unusually long.

Contraindications

History of hypersensitivity to mefloquine or related compounds.
History of seizures, neuropsychiatric disorders, or cardiac conduction abnormalities.

Precautions

Use cautiously in persons with psychiatric disorders, cardiac conduction issues, or concomitant use of drugs affecting QT interval.
Monitor for neuropsychiatric and cardiac side effects.

Adverse Reactions - Common

Nausea, vomiting, diarrhea (Common)
Dizziness, headache (Common)
Vivid dreams, insomnia (Common)

Adverse Reactions - Serious

Neuropsychiatric reactions (e.g., anxiety, paranoia, hallucinations) (Rare but serious)
Seizures (Rare)
QRS prolongation and QT interval prolongation, arrhythmias (Rare)

Drug-Drug Interactions

Alcohol, other neurotoxic drugs, cardiac QT prolonging drugs

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for neuropsychiatric symptoms, cardiac function (ECG if indicated), and ongoing assessment of mental status.

Diagnoses:

Risk for neuropsychiatric disturbances
Risk for cardiac arrhythmias

Implementation: Educate patient on potential side effects, advise on avoiding driving or operating heavy machinery if dizziness or neuropsychiatric symptoms occur.

Evaluation: Assess for emergence of adverse effects, ensure adherence, and monitor for symptom resolution.

Patient/Family Teaching

Inform about possible neuropsychiatric effects and to report any mood changes or hallucinations immediately.
Advise to avoid alcohol and other neurotoxic substances during therapy.
Instruct on importance of adherence to dosing schedule.

Special Considerations

Black Box Warnings:

Neuropsychiatric adverse reactions, including depression, hallucinations, psychosis, and suicidal thoughts.

Genetic Factors: Genetic sensitivity to neuropsychiatric side effects not fully understood.

Lab Test Interference: None significant.

Overdose Management

Signs/Symptoms: Nausea, vomiting, dizziness, neuropsychiatric disturbances, seizures, cardiac arrhythmias.

Treatment: Supportive therapy, cardiac monitoring, and seizure management as needed. No specific antidote.

Storage and Handling

Storage: Store at room temperature, protected from moisture and light.

Stability: Stable under recommended storage conditions.