What is Lariam?
Lariam is the brand name for Mefloquine, a quinoline-methanol antimalarial medicine first developed in the 1970s for use against Chloroquine-resistant strains of Plasmodium falciparum. Lariam has historically been widely prescribed for malaria prophylaxis due to its convenient once-weekly dosing schedule and efficacy against resistant malaria strains.
Lariam carries important psychiatric and neurological risks. Suitability requires stringent assessment; this page does not rank it universally as a second-line option. UK guidance and UK Lariam product information are cited explicitly and do not establish a Spanish product authorisation.
How does Lariam work?
Mefloquine’s exact mechanism is not established. UKMEAG describes it as suppressive prophylaxis; do not assume its mechanism is the same as chloroquine.
Mefloquine is a blood-stage antimalarial — it acts on the asexual stages of Plasmodium parasites once they have entered the bloodstream. It does not eliminate dormant liver-stage parasites (hypnozoites) of P. vivax or P. ovale.
Lariam’s long half-life of approximately 2–3 weeks means it persists in the body for an extended period, which accounts for both its once-weekly dosing convenience and the prolonged duration of side effects if they occur.
Who is Lariam for?
The choice depends on the itinerary, parasite resistance, medical history and ability to follow the regimen. Weekly dosing may be useful for long trips, but does not outweigh contraindications.
A doctor must assess personal psychiatric or seizure history, family history, cardiac conditions, liver function and interacting medicines. Family history informs risk assessment rather than automatically constituting a contraindication. Mefloquine must not be selected for destinations with documented resistance, including some areas of Southeast Asia.
Dosage
This is the UKMEAG adult prevention schedule. UK Lariam tablets contain 250 mg mefloquine as hydrochloride; the full-tablet prophylaxis dose applies above 45 kg. This is not a Spanish authorisation or a malaria-treatment regimen:
| Phase | Adult Dose | Timing |
|---|---|---|
| Pre-travel prophylaxis | 250 mg once weekly | Start 2–3 weeks before departure |
| During travel | 250 mg once weekly | Continue throughout stay |
| Post-travel | 250 mg once weekly | Continue for 4 weeks after leaving risk area |
The UK Lariam label itself starts 10 days before departure, with the second dose 3 days before departure. UKMEAG’s 2–3-week lead-in allows more time to assess tolerability. A prescriber must select the schedule for the actual product; do not combine schedules.
Lariam should be taken with food and a full glass of water, on the same day each week.
Side effects
Psychiatric and neurological reactions
Mefloquine can cause serious neuropsychiatric adverse events. These may include:
- Vivid or disturbing dreams, nightmares
- Insomnia or other sleep disturbances
- Anxiety, agitation, or restlessness
- Depression
- Mood changes
- Paranoia or unusual suspicion
- Hallucinations (auditory or visual)
- Confusion or disorientation
- Suicidal thoughts or self-endangering behaviour
Psychosis, suicidal behaviour and persistent neurological symptoms have been reported. Stop prophylaxis and seek immediate medical advice for new psychiatric or neurological symptoms so alternative malaria prevention can be arranged. Symptoms may persist for months or longer after stopping.
Other possible effects
- Nausea, vomiting, abdominal pain
- Dizziness or vertigo
- Headache
- Diarrhoea
- Fatigue
Other serious effects
- Cardiac effects: Bradycardia (slowing of the heart), QT prolongation — relevant for patients with existing cardiac conditions
- Seizures: A personal seizure history contraindicates prophylaxis; family history requires assessment
- Vestibular effects: Persistent dizziness or balance problems, which may continue after stopping the medicine
Lariam vs alternatives
| Medicine | Dosing | Neuropsychiatric Risk | SE Asia Use | Post-travel |
|---|---|---|---|---|
| Lariam (Mefloquine) | Weekly | Serious, potentially persistent reactions | Check local resistance | 4 weeks |
| Malarone | Daily | Product-specific risks require review | Check itinerary | 7 days |
| Doxycycline | Daily | Product-specific risks require review | Check itinerary | 4 weeks |
| Chloroquine | Weekly | Product-specific risks require review | Not recommended (resistance) | 4 weeks |
How to get Lariam online in Europe
Prescrivia is a technology intermediary connecting patients with independent doctors and licensed pharmacies. We do not provide medical services, prescribe, employ doctors, sell or dispense medicines.
- Assessment: Provide your symptoms or travel plans, medical history and all current medicines.
- Independent review: A doctor decides whether a prescription is clinically appropriate; Prescrivia does not guarantee a prescription.
- Dispensing: Any lawful dispensing is the responsibility of a licensed pharmacy, subject to the applicable rules and product availability.
In Spain, distance selling of prescription medicines is prohibited. An online assessment or a product label does not establish that a medicine can legally be supplied or delivered through this platform. This information does not change eligibility or fulfilment rules.
Important safety information
Do not take Lariam for prophylaxis under the UK label if you have: current or previous psychiatric disorders, including depression, generalised anxiety disorder, psychosis, schizophrenia, suicidal thoughts or attempts; any seizure history; allergy to mefloquine, quinine, quinidine or excipients; severe hepatic impairment; or a history of Blackwater fever (malaria-associated massive haemolysis with dark urine).
Halofantrine is prohibited during use and for 15 weeks after the last mefloquine dose. Ketoconazole also carries a QT-risk warning during this interval. UKMEAG advises against use with bupropion because of seizure risk.
Stop prophylaxis and seek immediate medical advice: for new abnormal dreams, insomnia, anxiety, depression, restlessness, confusion, hallucinations, neuropathy symptoms, severe dizziness or balance problems. Arrange alternative malaria prevention promptly. Palpitations, fainting or chest pain require urgent assessment.
Tell your doctor: about family psychiatric/seizure history, cardiac conduction disorders, pregnancy, breastfeeding, antiepileptics, beta-blockers and other heart-rhythm medicines. Prolonged use requires eye and liver checks. Do not drive if dizziness or balance problems impair you.
Pregnancy: The UK label advises against travel to malaria-endemic areas during pregnancy. It allows considering prophylaxis in any trimester under strict indications; this is not blanket reassurance or Spanish prescribing policy. Breastfeeding also requires individual medical advice.
The UK label advises avoiding mefloquine during breastfeeding as a precaution; seek advice based on the relevant guidance. Its lactose means patients with hereditary galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption must not take it. Complete oral live bacterial vaccinations at least 3 days before the first mefloquine dose.
Sources
- Lariam 250 mg: UK manufacturer product information
- UKMEAG 2026: malaria chemoprophylaxis
- FDA: mefloquine boxed warning, 2013 safety communication
- BOE: Real Decreto Legislativo 1/2015, article 3.5
General information, not individual prescribing advice. Fever during or after malaria-risk travel needs urgent medical assessment even after prophylaxis.
Frequently asked questions
- What is Lariam used for?
- Lariam (Mefloquine) is an antimalarial medicine used for the prevention and treatment of malaria, including malaria caused by Chloroquine-resistant strains of Plasmodium falciparum. The prevention schedule is weekly; malaria treatment uses a different regimen.
- What are the neuropsychiatric side effects of Lariam?
- Lariam carries a well-documented risk of neuropsychiatric side effects, which include vivid dreams, insomnia, anxiety, depression, paranoia, hallucinations, and in rare cases, more severe psychiatric events. The FDA introduced a boxed warning in the United States in 2013; the UK label also contains serious warnings. Stop prophylaxis and obtain immediate medical advice to arrange alternative malaria prevention if these symptoms occur.
- Who should not take Lariam?
- The UK label prohibits prophylaxis with current or previous psychiatric disorders or seizures, and use with relevant allergy, severe liver impairment or a history of Blackwater fever. Cardiac conduction disorders and family history need careful assessment; they are not the same as those listed contraindications.
- How early before travel should I start Lariam?
- UKMEAG guidance starts mefloquine 2–3 weeks before departure to a malaria-risk area. Starting early allows any neuropsychiatric side effects to become apparent before travel begins, giving time to switch to an alternative antimalarial if needed.
- Can I get Lariam online in Europe?
- An independent doctor must assess psychiatric, neurological and medical history. This page uses UK product information; it does not establish Spanish authorisation, stock or lawful supply.
Related treatments
Compare related options in the same wider treatment route.
Intermediary notice: Prescrivia connects patients with independent doctors and licensed pharmacies. We do not provide medical advice, employ doctors, or sell medicines. All medical decisions are made by independent healthcare professionals, and prescription-only medicines require a valid prescription. Treatment is not guaranteed — whether a prescription is issued depends on an independent doctor's clinical assessment.
Current review status is not yet confirmed. Enable JavaScript to load current review records.