Mefloquine

How it works

It is a blood schizonticide active against the erythrocytic stages of malaria parasites; its precise mechanism is not fully defined but is thought to involve interference with the parasite's haem detoxification within the food vacuole.

Prescribing in practice

• Neuropsychiatric adverse effects, including abnormal dreams, anxiety, depression and rarely psychosis, are recognised, and it is contraindicated in those with a history of certain psychiatric conditions or seizures, with MHRA advice highlighting these risks.
• When used for prophylaxis it should be started before travel so tolerability can be assessed and continued for the recommended period after leaving the malarious area.
• It can affect cardiac conduction and should be used cautiously with other agents that influence the QT interval or in relevant cardiac conditions.

Monitoring

Review for neuropsychiatric symptoms during prophylaxis and treatment, and reassess if such effects emerge.

Counselling the patient

• Stop the medicine and seek advice if you develop anxiety, depression, restlessness or confusion.
• Begin prophylaxis before you travel and continue it for the full period after you return.
• Take it with food and water on the same day each week as directed for prevention.

Evidence & guidelines

MHRA guidance details the neuropsychiatric risk profile of mefloquine and the importance of contraindications and patient counselling.