Methotrimeprazine Side Effects

Applies to methotrimeprazine: intramuscular solution.

General

The most commonly reported side effects included dry mouth, somnolence, hypotension, and convulsions.^[Ref]

Cardiovascular

• Common (1% to 10%): Heat stroke, hypotension, QT prolongation
• Uncommon (0.1% to 1%): Tachycardia, venous thromboembolism/fatal venous thromboembolism
• Rare (0.01% to 0.1%): Cardiac arrest, cardiac rhythm disturbances, ventricular arrhythmias, ventricular fibrillation, ventricular tachycardia
• Frequency not reported: Atrial arrhythmias, atrioventricular (AV) block, cardiac arrhythmias, deep vein thrombosis, ECG changes, orthostatic hypotension, postural hypotension, ST depression, sudden cardiac death, Torsade de pointes, T-wave changes, U-wave changes^[Ref]

Heat stroke occurred in hot and humid conditions.

Hypotension occurred with use, especially in older patients.

Orthostatic hypotension occurred with high initial oral doses or with initial parenteral doses.

Patients who develop Torsade de pointes should discontinue treatment and should be given therapy to correct imbalances (e.g., acid base disturbances, electrolyte imbalances, hypoxia).^[Ref]

Nervous system

• Common (1% to 10%): Drowsiness, sedation, somnolence
• Uncommon (0.1% to 1%): Convulsions, parkinsonism
• Rare (0.01% to 0.1%): Extrapyramidal effects
• Frequency not reported: Akathisia, akinesia with/without hypertonia, anticholinergic syndrome, early dyskinesia, epileptic seizures, hyperkinetic-hypertonic movements, motor excitation, neuroleptic malignant syndrome, oculogyric crises, spasmodic torticollis, tardive dyskinesia, trismus^[Ref]

Drowsiness, sedation, and/or somnolence usually occurred early in treatment, but gradually disappeared after the first few weeks and/or with a dose adjustment.

Extrapyramidal syndrome includes akathisia, akinesia with/without hypertonia (partially relieved by antiparkinsonian agents), hyperkinetic-hypertonic movements, and/or motor excitation. Extrapyramidal effects typically occurred after prolonged, high-dose treatment; the effect was treated with reductions in dose or with the addition of an antiparkinsonian agent.

Oculogyric crises, spasmodic torticollis, and trismus occurred with early dyskinesia.

Parkinsonism was prolonged with higher doses.

Tardive dyskinesia occurred with prolonged use, may recur if the neuroleptic is discontinued, and may resolve upon rechallenge or with an increase in dose. Antiparkinsonian agents may cause symptom exacerbation.^[Ref]

Gastrointestinal

• Common (1% to 10%): Dry mouth
• Uncommon (0.1% to 1%): Constipation/severe constipation
• Very rare (less than 0.01%): Fatal necrotizing enterocolitis/necrotizing enterocolitis
• Frequency not reported: Paralytic ileus^[Ref]

Severe constipation may occur with treatment, and laxatives may be needed to treat the condition. Patients should report any new or worsening constipation to their healthcare provider.^[Ref]

Other

• Common (1% to 10%): Asthenia
• Frequency not reported: Neonatal drug withdrawal syndrome, sudden death/unexplained sudden death, thermoregulation disorders^[Ref]

Asthenia usually occurred early in treatment, but gradually disappeared after the first few weeks.^[Ref]

Hematologic

• Uncommon (0.1% to 1%): Agranulocytosis, raised erythrocyte sedimentation rate (ESR)
• Frequency not reported: Granulocytopenia, leukocytopenia, neutropenia^[Ref]

Hypersensitivity

• Uncommon (0.1% to 1%): Allergic skin reactions/allergic dermatitis^[Ref]

Dermatologic

• Uncommon (0.1% to 1%): Photosensitivity/photosensitivity reaction^[Ref]

Genitourinary

• Uncommon (0.1% to 1%): Urinary retention
• Very rare (less than 0.01%): Priapism
• Frequency not reported: Amenorrhea, galactorrhea^[Ref]

Metabolic

• Uncommon (0.1% to 1%): Weight gain
• Frequency not reported: Acid base disturbances, diabetic ketoacidosis, electrolyte abnormalities, glucose intolerance/impaired glucose tolerance, hyperglycemia, hyponatremia^[Ref]

Weight gain usually occurred in patients receiving prolonged, high-dose treatment.^[Ref]

Hepatic

• Rare (0.01% to 0.1%): Cholestatic jaundice without liver damage, jaundice
• Frequency not reported: Cholestatic liver injury, hepatocellular liver injury, mixed liver injury^[Ref]

Psychiatric

• Frequency not reported: Anxiety reactions, confusional state, delirium, frigidity, impotence, indifference, mood changes^[Ref]

Endocrine

• Frequency not reported: Gynecomastia, hyperprolactinemia, hypogonadism, syndrome of inappropriate antidiuretic hormone (SIADH) secretion^[Ref]

Hyperprolactinemia may result in amenorrhea, frigidity, galactorrhea, gynecomastia, and impotence.^[Ref]

Respiratory

• Frequency not reported: Fatal pulmonary embolism/pulmonary embolism, hypoxia^[Ref]

Ocular

• Frequency not reported: Accommodation disorder, brown deposits in the anterior segment of the eye^[Ref]

Brown deposits in the anterior segment of the eye usually do not affect vision, and are caused by accumulation of the drug.^[Ref]

Musculoskeletal

• Frequency not reported: Decreased bone mineral density^[Ref]

Immunologic

• Frequency not reported: Positive serology for antinuclear antibodies without clinical lupus erythematosus^[Ref]

Further information

Methotrimeprazine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer