ADVERSE REACTIONS
Clinical
At the doses used for treatment of acute malaria infections, the
symptoms possibly attributable to drug administration cannot be distinguished
from those symptoms usually attributable to the disease itself.
Among subjects who received mefloquine for prophylaxis of malaria, the most
frequently observed adverse experience was vomiting (3%). Dizziness, syncope,
extrasystoles and other complaints affecting less than 1% were also
reported.
Among subjects who received mefloquine for treatment, the most frequently
observed adverse experiences included: dizziness, myalgia, nausea, fever,
headache, vomiting, chills, diarrhea, skin rash, abdominal pain, fatigue, loss
of appetite, and tinnitus. Those side effects occurring in less than 1% included
bradycardia, hair loss, emotional problems, pruritus, asthenia, transient
emotional disturbances and telogen effluvium (loss of resting hair). Seizures
have also been reported.
Two serious adverse reactions were cardiopulmonary arrest in one patient
shortly after ingesting a single prophylactic dose of mefloquine while
concomitantly using propranolol (see
PRECAUTIONS:
Drug Interactions), and encephalopathy of unknown etiology during
prophylactic mefloquine administration. The relationship of encephalopathy to
drug administration could not be clearly established.
Postmarketing
Postmarketing surveillance indicates that the same kind of
adverse experiences are reported during prophylaxis, as well as acute treatment.
Because these experiences are reported voluntarily from a population of
uncertain size, it is not always possible to reliably estimate their frequency
or establish a causal relationship to mefloquine exposure.
The most frequently reported adverse events are nausea, vomiting, loose
stools or diarrhea, abdominal pain, dizziness or vertigo, loss of balance, and
neuropsychiatric events such as headache, somnolence, and sleep disorders
(insomnia, abnormal dreams). These are usually mild and may decrease despite
continued use. In a small number of patients it has been reported that dizziness
or vertigo and loss of balance may continue for months after discontinuation of
the drug.
Occasionally, more severe neuropsychiatric disorders have been reported such
as: sensory and motor neuropathies (including paresthesia, tremor and ataxia),
convulsions, agitation or restlessness, anxiety, depression, mood swings, panic
attacks, memory impairment, confusion, hallucinations, aggression, psychotic or
paranoid reactions and encephalopathy. Rare cases of suicidal ideation and
suicide have been reported though no relationship to drug administration has
been confirmed.
Other less frequently reported adverse events include:
Cardiovascular Disorders
circulatory disturbances (hypotension, hypertension, flushing,
syncope), chest pain, tachycardia or palpitation, bradycardia, irregular heart
rate, extrasystoles, A-V block, and other transient cardiac conduction
alterations.
Skin Disorders
rash, exanthema, erythema, urticaria, pruritus, edema, hair loss,
erythema multiforme, and Stevens-Johnson syndrome.
Musculoskeletal Disorders
muscle weakness, muscle cramps, myalgia, and arthralgia.
Respiratory Disorders
dyspnea, pneumonitis of possible allergic etiology
Other Symptoms
visual disturbances, vestibular disorders including tinnitus and
hearing impairment, asthenia, malaise, fatigue, fever, hyperhidrosis, chills,
dyspepsia and loss of appetite.
Laboratory
The most frequently observed laboratory alterations which could
be possibly attributable to drug administration were decreased hematocrit,
transient elevation of transaminases, leukopenia and thrombocytopenia. These
alterations were observed in patients with acute malaria who received treatment
doses of the drug and were attributed to the disease itself.
During prophylactic administration of mefloquine to indigenous populations in
malaria-endemic areas, the following occasional alterations in laboratory values
were observed: transient elevation of transaminases, leukocytosis or
thrombocytopenia.
Because of the long half-life of mefloquine, adverse reactions to mefloquine
may occur or persist up to several weeks after discontinuation of the drug.
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