Central Nervous System
Sedation: The most common adverse reaction to DEMSER (metyrosine) is moderate
to severe sedation, which has been observed in almost all patients. It occurs
at both low and high dosages. Sedative effects begin within the first 24 hours
of therapy, are maximal after two to three days, and tend to wane during the
next few days. Sedation usually is not obvious after one week unless the dosage
is increased, but at dosages greater than 2000 mg/day some degree of sedation
or fatigue may persist.
In most patients who experience sedation, temporary changes in sleep pattern
occur following withdrawal of the drug. Changes consist of insomnia that may
last for two or three days and feelings of increased alertness and ambition.
Even patients who do not experience sedation while on DEMSER (metyrosine) may report symptoms
of psychic stimulation when the drug is discontinued.
Extrapyramidal Signs: Extrapyramidal signs such as drooling,
speech difficulty, and tremor have been reported in approximately 10 percent
of patients. These occasionally have been accompanied by trismus and frank parkinsonism.
Anxiety and Psychic Disturbances: Anxiety and psychic disturbances
such as depression, hallucinations, disorientation, and confusion may occur.
These effects seem to be dose-dependent and may disappear with reduction of
Diarrhea occurs in about 10 percent of patients and may be severe. Anti-diarrheal agents may be required if continuation of DEMSER (metyrosine) is necessary.
Infrequently, slight swelling of the breast, galactorrhea, nasal stuffiness,
decreased salivation, dry mouth, headache, nausea, vomiting, abdominal pain,
and impotence or failure of ejaculation may occur. Crystalluria (see PRECAUTIONS)
and transient dysuria and hematuria have been observed in a few patients. Hematologic
disorders (including eosinophilia, anemia, thrombocytopenia, and thrombocytosis),
increased SGOT levels, peripheral edema, and hypersensitivity reactions such
as urticaria and pharyngeal edema have been reported rarely.
Caution should be observed in administering DEMSER (metyrosine) to patients receiving phenothiazines or haloperidol because the extrapyramidal effects of these drugs can be expected to be potentiated by inhibition of catecholamine synthesis.
Concurrent use of DEMSER (metyrosine) with alcohol or other CNS depressants can increase
their sedative effects. (See WARNINGS and
PRECAUTIONS: Information for Patients.)
Laboratory Test Interference
Spurious increases in urinary catecholamines may be observed in patients receiving DEMSER (metyrosine) due to the presence of metabolites of the drug.