La méfloquine (Lariam^®) est utilisée dans le traitement et la prophylaxie des formes de paludisme résistantes à la chloroquine. Les effets secondaires neuropsychiatriques graves sont rares. Nous rapportons deux cas de troubles de l’humeur : le premier cas est un homme de 31 ans, sous prophylaxie antipaludique par méfloquine, qui a présenté une manie avec caractéristiques psychotiques. Le second cas est un épisode dépressif majeur (EDM) avec caractéristiques psychotiques chez un patient de 27 ans. Plusieurs facteurs peuvent augmenter le risque de survenue d’effets secondaires neuropsychiatriques sévères, d’où l’intérêt d’une sensibilisation des professionnels de santé quant à la recherche des facteurs de risque chez leurs patients, notamment les antécédents personnels ou familiaux de troubles psychiatriques.

Mefloquine (Lariam) is the drug of choice as malaria prophylaxis for travel to chloroquine-resistant areas. Severe neuropsychiatric side effects are rare. We report two clinical cases of mood disorders: mania and a major depressive episode with psychotic characteristics in two patients with mefloquine antimalarial prophylaxis.

A 31-year-old man had taken mefloquine at a rate of 250mg/week as malaria prophylaxis for his mission in Democratic Republic of Congo. He developed mania with psychotic symptoms after taking five tablets of 250mg of mefloquine. He exhibited an elevated mood and also developed delusions of grandeur, reference and persecution, with auditory hallucinations. The physical examination and the blood laboratory tests were normal. The patient was treated with an atypical neuroleptic (olanzapine 20mg/d) leading to a complete resolution of symptomatology at the end of 3 weeks.

A 27-year-old man presented a major depressive episode with psychotic symptoms after 1 week on his return from a stay in Democratic Republic of Congo, where he had taken mefloquine during 6 months as malaria prophylaxis (250mg/week). His physical examination and investigations (full blood test, serology and MRN) were normal. The patient was treated with clomipramine (150mg/d) and olanzapine (20mg/d). The outcome was favorable after 4 weeks.

Mefloquine is widely accepted as a safe and effective treatment and a prophylactic agent for chlorquine-resistant malaria. Common neuropsychiatric adverse effects of mefloquine can occur in up to 40% of patients, such as dizziness, sleep disturbances, anorexia, ataxia, and fatigue. Other more serious adverse reactions are rare. They are represented primarily by panic attacks, convulsions, acute psychosis, paranoid delusions, suicidal ideation, disorders of mood: major depressive episode and the manic excitation. The incidence of such neuropsychiatric effects is 1/10,000 to 1/15,000 during the prophylactic treatment. The causal mechanism for the side effects is not known. Several risk factors increasing the neurotoxicity of mefloquine can be identified, the patient with personal or family history of psychiatric disorders are more frequently concerned. Alcohol and the association with other drugs (like quinine) are two other risk factors.

It is relevant for medical practitioners to be aware of the severe neuropsychiatric side effects of mefloquine as malaria prophylaxis. It requires investigation of the risk factors such as personal or family history of psychiatric disorders.