Nortriptyline

Nortriptyline is used in several therapeutic areas that involve mood regulation and pain modulation.

• Major depressive disorder: alleviates depressive symptoms and improves mood in adult patients.
• Neuropathic pain: reduces pain intensity associated with peripheral nerve injury.
• Migraine prophylaxis: decreases frequency and severity of migraine attacks.

• Nortriptyline inhibits the reuptake of the neurotransmitters norepinephrine and serotonin at presynaptic neuronal membranes, leading to increased concentrations of these monoamines in the synaptic cleft. The elevated norepinephrine and serotonin enhance descending inhibitory pain pathways and modulate mood circuits in the central nervous system, contributing to its antidepressant, analgesic, and migraine‑preventive effects. It also exhibits mild antagonism at muscarinic, histamine H1, and α1‑adrenergic receptors, which may influence its side‑effect profile.

Nortriptyline may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Dry mouth: reduced salivary flow causing discomfort.
• Constipation: slowed gastrointestinal motility.
• Drowsiness: increased sedation, especially at treatment initiation.
• Weight gain: increased appetite or metabolic changes.
• Orthostatic hypotension: dizziness upon standing.

Serious or Rare Side Effects

• Cardiac arrhythmias: irregular heart rhythm, especially in overdose.
• Seizures: heightened risk in susceptible individuals.
• Serotonin syndrome: potentially life‑threatening when combined with serotonergic agents.

When prescribing nortriptyline, clinicians should consider several precautionary measures to ensure patient safety.

• Cardiac assessment: obtain baseline ECG in patients with heart disease.
• Age considerations: use lower doses and monitor closely in elderly patients.
• Drug interactions: review concomitant medications for serotonergic or QT‑prolonging agents.
• Psychiatric monitoring: watch for worsening depression or emergence of suicidal thoughts.
• Liver or kidney impairment: adjust dose if hepatic or renal function is compromised.
• Store at ambient temperature: keep tablets in the original container, protect from moisture and light.

Nortriptyline interacts with several medicines; awareness of these interactions helps prevent adverse outcomes.

Major Interactions (Avoid)

• MAO inhibitors: concurrent use can cause hypertensive crisis or serotonin syndrome.
• SSRIs or SNRIs: combined serotonergic activity increases risk of serotonin syndrome.
• Anticholinergic drugs: additive anticholinergic effects may exacerbate dry mouth, constipation, and urinary retention.

Moderate Interactions (Monitor Closely)

• CYP2D6 inhibitors (e.g., fluoxetine, quinidine): may raise nortriptyline plasma levels.
• QT‑prolonging agents (e.g., amiodarone, sotalol): increase risk of cardiac arrhythmias.
• Diuretics: may enhance orthostatic hypotension.