Nortriptyline

# Nortriptyline ## Overview - **Classification**: Tricyclic Antidepressant (TCA) - **Mechanism**: Primarily inhibits norepinephrine reuptake and, to a lesser extent, serotonin reuptake in the CNS. Also blocks histamine H1, alpha-1 adrenergic, and muscarinic acetylcholine receptors. ## Primary Indications 1. **Major Depressive Disorder** - Treatment of depressive symptoms. 2. **Neuropathic Pain** (Off-label) - Management of various chronic pain conditions. 3. **Migraine Prophylaxis** (Off-label) - Prevention of migraine headaches. 4. **Nocturnal Enuresis** (Off-label, limited use) - Bedwetting in children. ## Adult Dosing ### Standard Dosing **Major Depressive Disorder** - **Dose**: Initiate with **25 mg** - **Frequency**: Once daily at bedtime or in divided doses - **Route**: Oral - **Titration**: Increase gradually to **50-100 mg** daily. - **Maintenance**: **50-150 mg** daily. - **Maximum Dose**: **150 mg/day**. **Neuropathic Pain / Migraine Prophylaxis** - **Dose**: Initiate with **10-25 mg** - **Frequency**: Once daily at bedtime - **Route**: Oral - **Titration**: Increase by **10-25 mg** every 1-2 weeks. - **Usual Effective Range**: **25-100 mg** daily. ### Dose Adjustments - **Renal Impairment**: No specific dose adjustments needed. Use with caution due to active metabolites. - **Hepatic Impairment**: Use with caution, consider lower starting doses and slower titration. Monitor for adverse effects. - **Elderly Patients**: Start with lower doses (e.g., **10-25 mg** daily). Titrate slowly. Max dose generally **100 mg/day**. Higher risk of anticholinergic and cardiovascular adverse effects. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **Not recommended**. - **Special Notes**: Safety and efficacy not established. High risk of serious adverse effects. ### Infants (1-12 months) - **Dose**: **Not recommended**. - **Special Notes**: Safety and efficacy not established. ### Children (1-12 years) **Nocturnal Enuresis (Off-label)** - **Age (6-10 years)**: **10-20 mg** - **Age (11-16 years)**: **25-50 mg** - **Frequency**: Once daily 30 minutes before bedtime. - **Route**: Oral - **Maximum**: **50 mg/day**. - **Special Notes**: Use for limited duration. ECG monitoring recommended due to cardiac risks. **Depression (Off-label)** - **Dose**: Generally **not recommended** as first-line due to safety concerns. - **Special Notes**: If considered, requires expert consultation and close cardiac monitoring. ### Adolescents (13-18 years) **Depression (Off-label)** - **Dose**: Initiate with **25 mg** - **Frequency**: Once daily. - **Route**: Oral - **Titration**: Gradually increase to **50-75 mg** daily. - **Maximum**: **100-150 mg/day** (similar to adult dosing). - **Special Notes**: Increased risk of suicidal thoughts/behavior. Close monitoring for clinical worsening is essential. ECG monitoring recommended. ## Safety Information ### Contraindications - **Absolute**: Concomitant use with MAOIs (within 14 days). - **Absolute**: Acute recovery period after myocardial infarction (MI). - **Absolute**: Hypersensitivity to nortriptyline or other TCAs. - **Relative**: Uncontrolled narrow-angle glaucoma, urinary retention, severe cardiac disease (e.g., arrhythmias, heart block), hyperthyroidism, seizure disorders. ### Common Adverse Effects - **Very Common (>10%)**: Dry mouth, constipation, blurred vision, urinary retention, sedation, orthostatic hypotension. - **Common (1-10%)**: Dizziness, tremor, weight gain, nausea, headache, sweating. - **Serious but Rare**: Cardiac arrhythmias (e.g., QT prolongation, tachycardia), seizures, bone marrow depression, SIADH, serotonin syndrome. ### Key Drug Interactions - **MAOIs**: Risk of serotonin syndrome, hypertensive crisis, hyperpyrexia. **Contraindicated**. - **CNS Depressants (alcohol, benzodiazepines)**: Enhanced sedation, respiratory depression. Avoid concurrent use. - **CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine)**: Increased nortriptyline plasma levels, increased risk of toxicity. Monitor levels; dose reduction may be needed. - **Sympathomimetics (e.g., epinephrine, pseudoephedrine)**: Potentiated pressor effects. Use with caution. - **Anticholinergics**: Increased risk of severe anticholinergic effects (e.g., paralytic ileus, hyperthermia). ## Monitoring & Follow-up - **Before Treatment**: Baseline ECG (especially in elderly or with cardiac risk factors), blood pressure, pulse, weight, electrolyte levels, liver and renal function. Suicidality risk assessment. - **During Treatment**: Monitor plasma levels if indicated (target: **50-150 ng/mL**), blood pressure, pulse, weight, mental status changes, and suicidality (especially early in treatment or with dose changes). - **Clinical Signs**: Worsening depression, agitation, unusual behavioral changes, cardiac symptoms (palpitations, dizziness), excessive anticholinergic effects. ## Clinical Pearls - 💡 **Tip 1**: Administer once daily at bedtime to minimize daytime sedation. - 💡 **Tip 2**: Therapeutic drug monitoring (TDM) can be helpful to confirm compliance, identify toxicity, or guide dosing for non-responders. - 💡 **Tip 3**: Counsel patients on potential anticholinergic effects (e.g., dry mouth, constipation) and orthostatic hypotension. - 💡 **Tip 4**: Advise patients to avoid alcohol and other CNS depressants due to additive sedative effects. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.