Neuropsychiatric Side Effects Confirmed by Latest Lariam Research

Contact Jeanne Lese
February 2001

SAN RAFAEL, CA Five new studies, including a randomized, double-blind clinical trial, find significant scientific basis for the growing concern over side effects of mefloquine (Lariam®). Lariam is an FDA-approved antimalarial prescription drug from Hoffmann-La Roche. Four studies from the Netherlands, Sweden, Spain, and California find that Lariam causes significantly higher number of central nervous system and neuropsychiatric adverse events than other antimalarial drugs, especially when compared to its newest competitor Malarone® (atovaquone/proguanil). Roche defines “central nervous system” symptoms as “convulsions, depression, hallucinations, psychotic or paranoid reactions, anxiety, agitation, aggression, confusion, forgetfulness, hearing impairment, restlessness, sensory and motor neuropathies (including paresthesia), tinnitus and vestibular disorders, visual disturbances. Suicidal ideation has also been reported.” (Lariam Product Information, 1999). [emphasis added throughout]

The Studies

The randomized, double blind clinical trial from the Netherlands found that Lariam causes twice as many neuropsychiatric adverse reactions as Malarone:

Subjects receiving Malarone had a lower rate of treatment-related neuropsychiatric AEs [adverse events] compared to MFQ [mefloquine] (14% vs. 29%).” (D Overbosch et al., presented at the 40th annual Interscience Conference on Antimicrobial Agents and Chemotherapy, Toronto, 19 Sept. 2000.)

California researchers found that one in five people taking Lariam experience side effects severe enough to make them stop taking the drug and, as a consequence, increasing their risk of illness:

“Data herein indicates 1 in 5 individuals prescribed mefloquine reported adverse events with significant rate of therapy discontinuation, placing the traveler at risk of contracting malaria.” (B Ward and D Mathison, Scripps Clinic Travel Clinic, June 1999.)

The Denmark study focused on central nervous system side effects from Lariam and two other antimalarial drugs, finding that:

“…symptoms related to the central nervous system are more prevalent in mefloquine users and when symptoms develop, they are perceived as more severe.” (E Peterson et al., Journal of Travel Medicine, March 2000; 7:79-84)

CDC changes advice, manufacturer revises Lariam information

Recent action by the Centers for Disease Control (CDC) and Lariam’s manufacturer flags the importance of these five new research studies.

On February 1, 2001 the CDC changed the advice it gives travelers about the drugs recommended for malaria prevention: “Alternatives for travelers who cannot or choose not to take mefloquine include doxycycline or Malarone(TM).” Previously Lariam was the CDC’s “drug of choice” for malaria prevention.

In August 1999 Hoffmann-La Roche massively expanded the Lariam product information sheet (“PI”). Additions to the PI include:

  • more contraindications about who should NOT take Lariam,
  • a more extensive listing of reported physical and neuropsychiatric adverse events,
  • first-time warnings of reports of central and peripheral nervous system disorders (e.g. loss of balance and other balance-related problems),
  • an entire new section of information for patients, and
  • new cautions about prescribing Lariam for children.

Furthermore, the PI acknowledges for the first time that “because of the long half-life of mefloquine, adverse reactions to Lariam may occur or persist up to several weeks after the last dose.” It was previously thought that Lariam’s side effects could only occur during the course of treatment or immediately thereafter. The manufacturer has not yet defined the exact duration of “several weeks.” Accumulating anecdotal evidence indicates that symptoms of Lariam toxicity can persist for years after the drug is discontinued.

Roche did not issue a “Dear Doctor” letter when the company revamped the Lariam PI. Without an official alert, physicians are likely to miss the changes. Roche similarly delayed notifying physicians of reports of serious depression and suicide involving its acne drug Accutane (a registered trademark). (Lariam can also cause depression and suicide). Only after Congressional pressure from Michigan Congressman Bart Stupak did Roche send a Dear Doctor letter about Accutane. The Congressman’s son BJ committed suicide while being treated with the acne drug.

Inadequate warnings about Lariam’s possible dangers

Most patients receive inadequate warnings about Lariam’s side effects. Product Information sheets are written for doctors. The only warnings the patient may receive will come from the prescribing physician and/or the pharmacy that fills the prescription. US health officials seriously underestimate the severity of Lariam’s side effects.

Lariam Action USA

Lariam Action USA is an information and support service. Travelers need to know ALL the risks and benefits of any antimalarial drug BEFORE they can make an informed decision about which one to take. More than 1,000 people have voluntarily reported significant Lariam side effects to us since 1997. There are Lariam interest groups in the US, UK, Canada, Denmark, Ireland, New Zealand, and Switzerland. New groups are expected soon in Australia and France.

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Please contact Lariam Action USA at:

Lariam Action USA
64 El Pavo Real Circle
San Rafael, CA 94903-3521