Nortriptyline is a tricyclic antidepressant, or TCA, known by its brand names, Pamelor and Aventyl. The fundamental action of this drug involves altering the balance of chemical messengers in the brain called neurotransmitters. By influencing these substances, nortriptyline can affect mood and other bodily functions. This medication is the active metabolite of another tricyclic antidepressant, amitriptyline.
FDA-Approved Medical Applications
The United States Food and Drug Administration (FDA) has approved nortriptyline for the treatment of major depressive disorder in adults. Its therapeutic effect is believed to stem from its ability to inhibit the reuptake of specific neurotransmitters, particularly norepinephrine and to a lesser extent, serotonin. This action increases the concentration of these chemicals in the synapse, the small gap between nerve cells, allowing them to better regulate mood.
When a person begins taking nortriptyline for depression, the effects are not immediate. It can take several weeks of consistent use for the full therapeutic benefits to become apparent. The process allows the body to acclimate to the medication, which can help manage potential side effects.
Common Off-Label Uses
Beyond its approved use for depression, clinicians may prescribe nortriptyline for conditions not officially sanctioned by the FDA, a practice known as off-label use. One of the most widespread off-label applications is for the management of neuropathic pain, which is pain caused by nerve damage. Conditions such as diabetic neuropathy, postherpetic neuralgia (nerve pain after a shingles infection), and trigeminal neuralgia fall into this category.
The way nortriptyline alleviates nerve pain is thought to be distinct from its antidepressant mechanism. For pain, it is believed to work by blocking pain signal transmission in the central nervous system, particularly the spinal cord. This action helps to dampen the persistent pain signals that characterize neuropathic conditions.
Another common off-label use is for the prevention of migraine headaches. It is taken daily to reduce the frequency and severity of migraine attacks, rather than to treat an attack that is already in progress. Additionally, nortriptyline has been explored as an aid for smoking cessation. It can help reduce cravings and withdrawal symptoms associated with quitting tobacco. Patients should understand that these uses have not undergone the same rigorous FDA review for safety and efficacy as its use for depression.
Potential Side Effects and Risks
Treatment with nortriptyline can be accompanied by a range of potential side effects. The more common effects are often most noticeable when starting the medication and may diminish over time as the body adjusts. These include:
- Drowsiness
- Dry mouth
- Constipation
- Blurred vision
- Weight gain
More serious, though less frequent, risks are also associated with the medication. These can include cardiovascular effects such as irregular heart rhythms (arrhythmias) and a drop in blood pressure upon standing (postural hypotension), which can cause dizziness or fainting. In rare instances, seizures have been reported. Individuals with pre-existing heart conditions should discuss these risks with their doctor.
The FDA has issued a black box warning for nortriptyline and other antidepressants regarding an increased risk of suicidal thinking and behavior. This risk is most pronounced in children, adolescents, and young adults, particularly during the initial months of treatment or when the dosage is changed. Patients and their families should be vigilant for any worsening of depression, unusual changes in behavior, or the emergence of suicidal thoughts.
Important Considerations for Use
Proper management of nortriptyline therapy involves several considerations to ensure safety and effectiveness. Dosing is started at a low level and then gradually increased, or titrated, based on the patient’s needs and response. This approach helps to minimize side effects while finding the most effective dose. Doses should not exceed 150 mg per day.
It is important not to stop taking nortriptyline abruptly. Discontinuing the medication suddenly can lead to withdrawal symptoms, which may include nausea, headache, and a general feeling of malaise. A doctor will recommend a gradual tapering of the dose to allow the body to adjust slowly.
Certain drug interactions can be dangerous. Nortriptyline should not be taken with a class of drugs called monoamine oxidase inhibitors (MAOIs). Combining these medications can lead to a serious condition known as serotonin syndrome. Patients must inform their healthcare provider of all other medications they are taking, including over-the-counter drugs and supplements. The medication is also not recommended for individuals who are recovering from a recent heart attack.