Nortriptyline
Nortriptyline is a tricyclic antidepressant indicated for the treatment of depression. It is the active metabolite of amitriptyline and is often preferred among tricyclics due to its more favorable side effect profile, particularly lower sedation and anticholinergic effects compared to other tricyclic antidepressants.
Clinical Overview
Primary Clinical Applications
Nortriptyline is indicated for depression treatment and is commonly used off-label for chronic pain conditions, migraine prevention, and neuropathic pain. It is often chosen when a tricyclic is needed but better tolerability is desired compared to amitriptyline.
Mechanism and Clinical Benefits
Nortriptyline primarily inhibits norepinephrine reuptake with some serotonin reuptake inhibition. This mechanism provides antidepressant effects and analgesic properties for chronic pain conditions. It has a well-defined therapeutic window for plasma levels.
Therapeutic Monitoring
Nortriptyline has established therapeutic plasma level ranges (50-150 ng/mL), allowing for therapeutic drug monitoring to optimize efficacy and minimize toxicity. This monitoring capability is particularly valuable in elderly patients or those with medical comorbidities.
Key Clinical Points
Therapeutic window of 50 to 150 ng/mL
Unusually among antidepressants, nortriptyline has both a floor and a ceiling: levels above the range are associated with reduced rather than greater efficacy. Monitoring is genuinely useful rather than merely available.
The active metabolite of amitriptyline
Choosing nortriptyline gives the noradrenergic effect without the sedation and anticholinergic burden of the parent compound, which is why it is generally preferred where a tricyclic is indicated.
Widely used for chronic and neuropathic pain
Off-label use at 10 to 75 mg daily for chronic pain and migraine prevention is common and typically at lower doses than the antidepressant range.
Pregnancy Category D
Avoid where possible. Contraindicated after recent myocardial infarction and within fourteen days of an MAOI.
CYP2D6 status matters
Poor metabolisers require reduced doses, and CYP2D6 inhibitors substantially raise levels. This is where therapeutic drug monitoring earns its place.
Prescribing Information
Dosing & Administration
Depression – Adults:
- Initial: 25 mg 3-4 times daily
- Alternative: 75-100 mg daily at bedtime
- Maintenance: 75-100 mg daily
- Maximum: 150 mg daily
Elderly/Adolescents:
- Initial: 10-25 mg daily at bedtime
- Maintenance: 25-75 mg daily
Chronic Pain (off-label):
- Initial: 10-25 mg at bedtime
- Target: 50-75 mg daily
Indications
- Depression
- Off-label: Chronic pain, neuropathic pain, migraine prevention
Contraindications
- Recent myocardial infarction
- MAOI use within 14 days
- Known hypersensitivity to tricyclic antidepressants
- Concurrent use with linezolid or methylene blue
Warnings & Precautions
- Boxed Warning: Increased suicidal risk in patients under 25 years
- Cardiac effects: Monitor ECG in patients with cardiac disease
- Anticholinergic effects: Use caution in elderly patients
- Seizure risk: Lower seizure threshold
- Orthostatic hypotension: Monitor blood pressure
Drug Interactions
- MAOIs: Contraindicated – risk of serotonin syndrome
- CNS depressants: Enhanced sedation
- Anticholinergic drugs: Additive anticholinergic effects
- CYP2D6 inhibitors: Increased nortriptyline levels
- Sympathomimetics: Enhanced pressor response
Adverse Reactions
Common:
- Dry mouth, constipation, blurred vision, drowsiness
Cardiovascular:
- Orthostatic hypotension, tachycardia, conduction abnormalities
Special Populations
- Pregnancy: Category D – avoid if possible
- Elderly: Lower starting dose, monitor for anticholinergic effects
- Cardiac disease: Obtain baseline ECG, monitor closely
- CYP2D6 poor metabolizers: Reduced dosing may be needed
Frequently Asked Questions
What is Nortriptyline used for?
Nortriptyline is a tricyclic antidepressant indicated for the treatment of depression. It is the active metabolite of amitriptyline and is often preferred among tricyclics due to its more favorable side effect profile, particularly lower sedation and anticholinergic effects compared to other tricyclic antidepressants.
What class of drug is Nortriptyline?
Nortriptyline is classified as: Tricyclic Antidepressant.
Therapeutic window of 50 to 150 ng/mL?
Unusually among antidepressants, nortriptyline has both a floor and a ceiling: levels above the range are associated with reduced rather than greater efficacy. Monitoring is genuinely useful rather than merely available.
The active metabolite of amitriptyline?
Choosing nortriptyline gives the noradrenergic effect without the sedation and anticholinergic burden of the parent compound, which is why it is generally preferred where a tricyclic is indicated.
Widely used for chronic and neuropathic pain?
Off-label use at 10 to 75 mg daily for chronic pain and migraine prevention is common and typically at lower doses than the antidepressant range.
Pregnancy Category D?
Avoid where possible. Contraindicated after recent myocardial infarction and within fourteen days of an MAOI.
Source: FDA prescribing information (DailyMed)