Tricyclic or cyclic antidepressants (TCAs) are an early type of antidepressant. They are a good choice for those whose depression is resistant to other drugs, but some may find their side effects unpleasant.
TCAs were first introduced in the late 1950s, and they’re still considered effective for treating depression. However, they are not often used as a first treatment.
The different cyclic antidepressants that are currently available include:
- desipramine (Norpramin)
- imipramine (Tofranil)
- nortriptyline (Pamelor)
- protriptyline (Vivactil)
- trimipramine (Surmontil)
Clinicians usually only prescribe tricyclic antidepressants after other drugs have failed to relieve depression. Tricyclic antidepressants help keep more serotonin and norepinephrine available to your brain. These chemicals are made naturally by your body and are thought to affect your mood. By keeping more of them available to your brain, tricyclic antidepressants help elevate your mood.
Some tricyclic antidepressants are also used to treat other conditions, mostly in off-label uses. These conditions include obsessive compulsive disorder (OCD) and chronic bedwetting. In lower doses, cyclic antidepressants are used to prevent migraines and to treat chronic pain. They are also sometimes used to help people with panic disorder.
Tricyclic antidepressants treat depression, but they have other effects on your body as well. They can affect automatic muscle movement for certain functions of the body, including secretions and digestion. They also block the effects of histamine, a chemical found throughout your body. Blocking histamine can cause effects such as drowsiness, blurred vision, dry mouth, constipation, and glaucoma. These may help explain some of the more troublesome side effects associated with these drugs.
Tricyclic antidepressants are more likely to cause constipation, weight gain, and sedation than other antidepressants. However, different drugs have different effects. If you have a troublesome side effect on one tricyclic antidepressant, tell your doctor. Switching to another cyclic antidepressant may help.
Possible side effects of tricyclic antidepressants include:
- dry mouth
- dry eyes
- blurred vision
- seizure (especially with maprotiline)
- urinary retention
- sexual dysfunction
- low blood pressure
- weight gain (especially with amitriptyline, imipramine, and doxepin)
People who drink alcohol frequently should avoid tricyclic antidepressants. Alcohol lessens the antidepressant action of these drugs. It also increases their sedating effects.
Tricyclic antidepressants can cause harmful side effects if you take them with certain medications, including epinephrine (Epi-Pen) and cimetidine (Tagamet). Tricyclic antidepressants can increase the effects of epinephrine on your heart. This can lead to high blood pressure and problems with your heart rhythm. Cimetidine can increase levels of tricyclic antidepressant in your body, making side effects more likely.
Other drugs and substances can also interact with tricyclic antidepressants. It’s important for you to tell your doctor about all drugs and substances you use. Your doctor can help you avoid any interactions.
These drugs can make some conditions worse. People with the following conditions should avoid tricyclic antidepressants:
- angle-closure glaucoma
- enlarged prostate
- urinary retention
- heart problems
- thyroid problems
Tricyclic antidepressants also affect blood sugar levels, so people with diabetes who take these drugs may need to check their blood sugar level more frequently.
Pregnant women or women who are breastfeeding should talk to a doctor before using tricyclic antidepressants. The doctor will help weigh any possible risks to the mother or baby against the benefit of using these drugs.
Tricyclic antidepressants are effective, but they aren’t for everyone. They likely won’t be the first antidepressant your doctor has you try. This is mostly due to their potential for side effects.
If you are prescribed these drugs, talk with your doctor about any side effects you have. You should tell your doctor if you feel you can’t tolerate the side effects before changing your dosage or stopping treatment with these drugs. Abruptly stopping tricyclic antidepressant treatment can cause:
- flu-like symptoms
Your doctor will taper your dosage over time to avoid these effects.