Mefloquine is the name of an active ingredient used to treat and prevent malaria. Due to its severe side effects, the manufacturer has stopped selling the drug in Germany.
What is mefloquine?
Mefloquine was jointly developed by Swiss pharmaceutical company F. Hoffmann-La-Roche AG and a U.S. Army institute to treat the tropical disease malaria. Prevention is also possible with the synthetic drug. Mefloquine is available only on prescription and requires the presentation of a patient passport. In addition, a list of possible contraindications must be filled out before the prescription is issued. The reason for this is the drug’s pronounced psychiatric and neurological side effects, which caused controversy when it was first introduced. Mefloquine was associated with several suicides, suicide attempts and suicidal ideation. However, no clear evidence was found. In Germany, mefloquine was previously available under the trade name Lariam. In recent years, however, sales of the drug have declined in this country, so that it has become less important for malaria prophylaxis. Since 2013, the drug can only be prescribed under special conditions. In February 2016, the manufacturer Roche decided to abandon the approval of Lariam in Germany. This was followed in April 2016 by the discontinuation of sales of the mefloquine preparation. However, pharmacies and wholesalers may continue to sell the drug for another two years. Following this period, mefloquine can be imported from abroad. Due to the severe side effects, the active ingredient is no longer recommended for emergency self-treatment. The DTG (German Society for Tropical Medicine), however, continues to give mefloquine a high priority for the treatment of children and pregnant women, provided that the precautionary measures are observed. This is especially true for travel to areas where there is a high risk of malaria.
Pharmacologic action
Mefloquine exerts an antiparasitic effect and can be used against malaria parasites such as Plasmodium malariae, Plasmodium vivax, Plasmodium falciparum, and Plasmodium ovale. In its structure, the synthetic drug is related to other antimalarials such as chloroquine and quinine. Its properties include disrupting the pathogens‘ key metabolic processes. As a result, the parasites eventually die. The human body absorbs mefloquine well and it binds extensively to plasma proteins. The plasma half-life is approximately 20 days. Excretion of the active ingredient occurs primarily in the stool. Two to three weeks may pass before mefloquine is excreted from the organism again. As a result, the side effects of the drug also often show up after several weeks.
Medical use and application
The uses of mefloquine include both treatment and emergency treatment of malaria. This is especially true for the control of the malaria pathogen Plasmodium falciparum, which is difficult to treat with other antimalarial preparations. If Plasmodium vivax malaria is treated with mefloquine, further treatment of the parasites in the liver with other antimalarial preparations is necessary to prevent relapses. These include primaquine. Mefloquine can also be taken to prevent malaria. However, this only applies if the affected person is traveling to regions where Plasmodium falciparum strains occur. In case of doubt, a specialized tropical physician should be consulted for advice. Mefloquine is administered in the form of tablets. For malaria prophylaxis, the drug is taken once a week after a meal. The prophylaxis should be started one week before the trip. After the end of the trip, the patient must continue taking the drug for another four weeks. While taking mefloquine, the patient should always carry the enclosed patient passport and present it to any responsible physician.
Risks and side effects
Psychiatric and neurologic symptoms may result from the use of mefloquine. The most common symptoms include unusual dreams, insomnia, dizziness, disturbances in balance, drowsiness, nausea, vomiting, headache, abdominal pain, and diarrhea.Other possible side effects include depression, aggression, states of confusion, hallucinations, panic attacks, delusions of persecution, reactions resembling psychosis, paraesthesia in the limbs, unsteadiness of gait, tremors, forgetfulness, and fainting. Epileptics are at increased risk of seizures. In addition, mefloquine is attributed to trigger suicidal intentions. If the described symptoms occur during mefloquine use, stop taking the active substance immediately and inform the attending physician. The physician has the option of prescribing a different antimalarial drug. Because mefloquine has an unusually long residence time in the body, side effects can still occur weeks after the end of therapy. If the patient suffers from hypersensitivity to mefloquine or similar substances such as quinidine or quinine, treatment with the active substance must not be given. This also applies in the presence of severe liver dysfunction and blackwater fever, which is a severe malaria complication with hemoglobinuria. So-called stand-by emergency treatment with mefloquine must not take place if depression, schizophrenia, psychosis, general anxiety disorders or mental disorders are present. The drug should also not be administered after suicide attempts or in cases of self-endangering behavior. The simultaneous use of mefloquine and other medications may cause interfering interactions. Therefore, it must not be administered together with agents with which there is a relationship. These are chloroquine, quinine, quinine sulfate and quinidine. There is a risk of heartbeat changes and seizures as a result. The effect of mefloquine is weakened by a simultaneous intake of St. John’s wort extracts. The same effect occurs with parallel intake of the antibiotic rifampicin.
