Nurses Compass
Drug Guide
Imipramine Pamoate
Classification
Therapeutic: Antidepressant, Tricyclic Antidepressant (TCA)
Pharmacological: Serotonin and Norepinephrine Reuptake Inhibitor with Anticholinergic Properties
FDA Approved Indications
- Major depressive disorder
- Enuresis (urinary incontinence, especially in children)
Mechanism of Action
Imipramine Pamoate inhibits reuptake of serotonin and norepinephrine in the central nervous system, increasing their levels in synaptic clefts. It also has anticholinergic and sedative effects, contributing to its therapeutic action and side effect profile.
Dosage and Administration
Adult: Typically 75-300 mg daily, divided into 1-3 doses; dosage adjusted based on response and tolerability.
Pediatric: For enuresis: 25-50 mg at bedtime, titrated as needed up to 75 mg.
Geriatric: Start at lower doses (e.g., 25-50 mg at bedtime) due to increased sensitivity and risk of side effects.
Renal Impairment: Use with caution; dosage adjustments may be necessary.
Hepatic Impairment: Use with caution; start at lower doses and monitor closely.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed; crosses the blood-brain barrier.
Metabolism: Primarily metabolized in the liver via CYP2D6 enzymes.
Excretion: Excreted primarily in urine.
Half Life: Approximately 8-16 hours, variable among individuals.
Contraindications
- Known hypersensitivity to imipramine or other TCAs.
- Recent myocardial infarction.
- Use of monoamine oxidase inhibitors (MAOIs) within 14 days.
Precautions
- History of seizures, bipolar disorder, glaucoma, urinary retention, QT prolongation, or suicidal ideation; monitor closely.
Adverse Reactions - Common
- Dry mouth (Common)
- Drowsiness (Common)
- Dizziness (Common)
- Constipation (Common)
Adverse Reactions - Serious
- Cardiac arrhythmias (Rare but serious)
- Suicidal thoughts or behavior (Monitor closely, especially in young adults and adolescents)
- Serotonin syndrome (Rare)
Drug-Drug Interactions
- Monoamine oxidase inhibitors (MAOIs)
- Other serotonergic agents (SSRIs, SNRIs, triptans)
- CNS depressants (alcohol, sedatives)
- Cimetidine, quinidine
Drug-Food Interactions
- Avoid alcohol and CNS depressant foods
Drug-Herb Interactions
- St. John’s Wort, Ginseng
Nursing Implications
Assessment: Monitor mental health status, suicidal ideation, cardiac function (ECG), hepatic and renal functions.
Diagnoses:
- Risk for suicidal ideation
- Risk for cardiac arrhythmias
Implementation: Administer dose at bedtime to minimize sedative effects. Monitor for adverse effects and therapeutic efficacy.
Evaluation: Assess mood improvement and side effect occurrence.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not abruptly stop medication.
- Report worsening mood, suicidal thoughts, or side effects.
- Be cautious about driving or operating machinery until effects are known.
Special Considerations
Black Box Warnings:
- Increased risk of suicidal thoughts and behavior in children, adolescents, and young adults.
Genetic Factors: CYP2D6 poor metabolizers may have increased plasma levels.
Lab Test Interference: Possible false results in certain cardiac assays.
Overdose Management
Signs/Symptoms: Agitation, confusion, hallucinations, seizures, arrhythmias, coma, hypotension.
Treatment: Supportive care, activated charcoal if early, cardiovascular monitoring, use of sodium bicarbonate for cardiac arrhythmias, and intensive care as needed.
Storage and Handling
Storage: Store at room temperature away from light and moisture.
Stability: Stable when stored properly.