Nortriptyline Side Effects: What to Expect and When to Call Your Doctor

Nortriptyline has a well-understood side effect profile after more than 60 years of clinical use. Most side effects are manageable, particularly with careful dose titration. But some side effects require prompt medical attention.

This guide covers everything you need to know: what to expect when starting nortriptyline, which effects are temporary, which require a doctor call, and tips to manage the most common complaints.

IMPORTANT: Boxed Warning — Suicidal Thoughts

Like all antidepressants, nortriptyline carries an FDA boxed warning about increased risk of suicidal thinking and behavior in children, adolescents, and young adults (up to age 24), particularly in the first few months of treatment or when the dose is changed.

If you or someone you know is experiencing thoughts of self-harm, call or text 988 (Suicide and Crisis Lifeline) or call 911 immediately. Always report worsening depression, agitation, or unusual behavior changes to your doctor right away.

Common Side Effects of Nortriptyline

Most common side effects stem from nortriptyline's anticholinergic activity (blocking acetylcholine) and its effects on the central nervous system. These tend to be most pronounced when starting the medication and often improve over the first few weeks:

Dry mouth: Very common. Sip water frequently, chew sugar-free gum, or use an over-the-counter saliva substitute. Dental hygiene is important since chronic dry mouth increases cavity risk.

Constipation: Increase dietary fiber, fluids, and physical activity. Your doctor may recommend a stool softener or mild laxative if constipation persists.

Sedation/drowsiness: Often improves after the first few weeks. Taking nortriptyline at bedtime rather than during the day can help. Do not drive until you know how this medication affects you.

Dizziness/orthostatic hypotension: Nortriptyline can cause a drop in blood pressure when you stand up. Rise slowly from sitting or lying positions to reduce dizziness. This effect is less pronounced with nortriptyline than with amitriptyline.

Blurred vision: Anticholinergic effect. Usually temporary. Report significant or persistent vision changes to your doctor.

Urinary retention: Difficulty urinating is more common in older men and those with enlarged prostates. Report difficulty urinating to your doctor.

Weight changes: Nortriptyline can cause weight gain or, less commonly, weight loss. Monitor your weight and discuss with your doctor if changes are significant.

Fast heartbeat (tachycardia): A mild increase in heart rate is common. Significant palpitations or irregular heartbeat should be reported to your doctor.

Increased sweating: Some patients experience excessive sweating, particularly at night.

Serious Side Effects: Call Your Doctor Right Away

The following side effects are less common but require prompt medical evaluation:

Irregular or fast heartbeat, chest pain: Nortriptyline can cause QT prolongation, a heart rhythm change that can lead to dangerous arrhythmias. Any chest pain, fainting, or irregular heartbeat is an emergency.

Serotonin syndrome symptoms: Agitation, confusion, rapid heart rate, high fever, muscle twitching, or diarrhea — especially if you've taken any other serotonergic medication. This is a medical emergency.

Severe vision changes or eye pain: Nortriptyline can increase eye pressure and trigger acute angle-closure glaucoma in susceptible individuals. Sudden eye pain, redness, or vision loss requires emergency evaluation.

Seizures: Nortriptyline lowers the seizure threshold. Any new seizure activity is a medical emergency.

Signs of mania: Elevated or irritable mood, racing thoughts, decreased need for sleep, impulsive behavior. Nortriptyline can trigger manic episodes in patients with undiagnosed bipolar disorder.

Suicidal thoughts: Call 988 (Suicide and Crisis Lifeline) or your doctor immediately if you experience thoughts of self-harm.

Tips to Manage Common Side Effects

Most nortriptyline side effects are most bothersome in the first 2-4 weeks and improve as your body adjusts. Strategies that help:

Start at a low dose (typically 10-25 mg/day) and increase gradually to reduce severity

Take nortriptyline at bedtime — sedation becomes a sleep aid rather than a daytime problem

Stay well hydrated to counteract dry mouth and constipation

Avoid alcohol completely — it significantly enhances CNS depressant effects

Do not drive or operate heavy machinery until you know how nortriptyline affects your alertness

When Do Side Effects Usually Improve?

Anticholinergic side effects (dry mouth, constipation, blurred vision) often peak in the first 1-2 weeks and gradually improve as your body adjusts. Sedation also typically diminishes after 2-4 weeks. If side effects remain intolerable after 3-4 weeks, talk to your prescriber about adjusting the dose or timing.

For information about which medications can make side effects worse, see our guide on nortriptyline drug interactions.