mefloquine hydrochloride

mefloquine hydrochloride

Lariam

Pharmacologic class: 4-quinolinemethanol derivative, quinine analog

Therapeutic class: Antimalarial

Pregnancy risk category C

Action

Unknown. Thought to increase intravesicular pH in parasite acid vesicles and form complexes with hemin, inhibiting parasite development.

Availability

Tablets: 250 mg

⊘Indications and dosages

➣ Acute malarial infection

Adults: 1,250 mg P.O. as a single dose

Children: 20 to 25 mg/kg P.O. in two divided doses given 6 to 8 hours apart

➣ Malaria prophylaxis

Adults and children weighing more than 45 kg (99 lb): 250 mg P.O. once weekly on same day each week, starting 1 week before entering endemic area and continuing for 4 weeks after leaving area

Children weighing 31 to 45 kg (67 to 99 lb): 187.5 mg P.O. q week

Children weighing 20 to 30 kg (44 to 66 lb): 125 mg P.O. q week

Children weighing 10 to 20 kg (22 to 44 lb): 62.5 mg P.O. q week

Children weighing 5 to 10 kg (11 to 22 lb): 31.25 mg P.O. q week

Contraindications

• Hypersensitivity to drug, related agents (quinine, quinidine), or excipients

Precautions

Use cautiously in:
• cardiac disorders, seizure disorders
• pregnant or breastfeeding patients
• children.

Administration

• Don't give on empty stomach. Administer with at least 240 ml of water.
• Know that after completing mefloquine therapy for acute malarial infection, patient should receive primaquine (or other 8-aminoquinolone) to prevent relapse.

Route	Onset	Peak	Duration
P.O.	Unknown	7-24 hr	Unknown

Adverse reactions

CNS: dizziness, syncope, headache, psychotic changes, depression, hallucinations, confusion, anxiety, fatigue, vertigo, seizures

EENT: blurred vision, tinnitus

GI: nausea, vomiting, diarrhea, loose stools, abdominal discomfort, anorexia

Hematologic: leukopenia, thrombocytopenia

Musculoskeletal: myalgia

Skin: rash

Other: fever, chills

Interactions

Drug-drug. Beta-adrenergic blockers, quinidine, quinine: ECG abnormalities, cardiac arrest

Chloroquine, quinine: increased risk of seizures

Valproic acid: decreased valproic acid blood level, loss of seizure control

Drug-diagnostic tests. Hematocrit, platelets, white blood cells: decreased values

Transaminases: transient increases

Patient monitoring

☞ Monitor patient with acute Plasmodium vivax malaria who is at high risk for relapse. Because drug doesn't eliminate exoerythrocytic (hepatic-phase) parasites, patient should receive primaquine after mefloquine therapy.
☞ Watch for psychiatric symptoms, such as acute anxiety, depression, restlessness, or confusion. These may precede more serious psychiatric events.
• Evaluate hepatic function during prolonged prophylactic therapy.
☞ In patients receiving related drugs (such as quinine, quinidine, or chloroquine) concurrently, be alert for ECG abnormalities and seizures. Separate administration times by at least 12 hours.
☞ Closely monitor patients with serious or life-threatening Plasmodium falciparum infection. Be aware that they should receive I.V. antimalarial drugs and that mefloquine may be used to complete course of therapy.

Patient teaching

• Tell patient to take with full glass of water and not on empty stomach.
• In prophylactic use, instruct patient to take first dose 1 week before departure and to continue therapy as prescribed upon return. Tell him to take drug on same day each week.
• Advise patient to report fever after returning from malarious area.
• Inform patient that malaria prophylaxis should include protective clothing, insect repellent, and bed netting.
☞ Tell patient to immediately report psychiatric symptoms (such as acute anxiety, depression, restlessness, or confusion) and to stop taking drug.
• Caution patient to avoid driving and other hazardous activities because drug may cause dizziness.
• Instruct patient to have periodic ophthalmic exams, because drug may cause eye damage.
• Tell female patient to inform prescriber if she is pregnant.
• Advise female patient not to breastfeed while taking drug.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.