Tricyclic and tetracyclic antidepressants (TCAs) were some of the first medications to treat depression. Doctors don’t prescribe them as much as they used to. Other drugs have replaced them, mainly selective serotonin reuptake inhibitors (SSRIs). But they may be an option if you’ve tried more than one of the newer antidepressants and they don’t work for you. Here’s what you need to know.
How Cyclic Antidepressants Work
Cyclic antidepressants boost the levels of serotonin and epinephrine in the brain. These are neurotransmitters that affect your mood. These drugs are called “cyclic” because of their 3- or 4-ring chemical structure.
Types of Cyclic Antidepressants
There are 10 TCAs approved to treat depression. They are:
Side Effects of Cyclic Antidepressants
Cyclic antidepressants tend to cause more problems because they affect other neurotransmitters, not just serotonin and epinephrine. One review of several studies found more patients stopped taking TCAs than SSRIs because of the side effects. They can include:
- Drowsiness
- Blurry vision
- Trouble pooping (constipation)
- Dry mouth
- A drop in blood pressure when you stand up (may cause lightheadedness)
- Urine retention (when your bladder doesn’t empty all the way)
- Weight loss
- Stronger appetite (may lead to weight gain)
- Sweating a lot
- Tremor
- Sexual problems (like low sex drive)
Side effects of SSRIs can include:
- Nausea
- Vomiting
- Diarrhea
- Headache
- Drowsiness
- Dry mouth
- Trouble sleeping
- Nervousness, agitation, or restlessness
- Dizziness
- Weight loss
- Stronger appetite (may lead to weight gain)
- Sexual problems (like low sex drive)
In general, these TCAs are more likely to make you sleepy or lead to weight gain:
- Amitriptyline
- Doxepin
- Imipramine
- Trimipramine
People who take these medications seem to handle the side effects of nortriptyline and desipramine better than other TCAs.
The main reason doctors switched to SSRIs and other antidepressants is because of the risks of overdose and suicide with TCAs. One study found these were much lower in patients taking SSRIs. Your doctor may not prescribe TCAs if you are at risk for taking your own life. If they do, they’ll likely give you very small amounts -- about a 1-week supply. Or they may have someone close to you keep the medicine and give it to you as you need it.
Other Health Conditions and Cyclic Antidepressants
Cyclic antidepressants may cause problems if you have certain health conditions. Talk to you doctor if you have any of these:
- Glaucoma
- An enlarged prostate
- Heart problems
- Diabetes
- Liver disease
- History of seizures
Ask your doctor if TCAs are OK if you’re pregnant.
Cyclic Antidepressants and Drug Interactions
Always talk to your doctor about any supplements or medications you take before you start your prescription. Cyclic antidepressants can interact with many common medications. Drinking alcohol while you take them could make you drowsy and affect your coordination.
Your body needs serotonin to regulate your mood, as well as functions like appetite, digestion, and sleep. But if you have too much of it in your system, you can have serious side effects. This is called serotonin syndrome. It’s rare, but it can happen if you:
- Increase your antidepressant dosage
- Combine antidepressants
- Take certain medications, including ones for nausea and migraines
- Take illegal drugs, such as LSD or cocaine
- Add supplements to your diet that boost serotonin, such as St. John’s wort
Symptoms include:
- Anxiety
- Fever
- Sweating
- Confusion
- Tremors
- Restlessness
- Lack of coordination
- Major changes in blood pressure
- A rapid heart rate
These symptoms will show up within hours after you take a higher dose of your medication or combine them with a supplement that raises serotonin. They usually go away once your levels get back to normal, but if you don’t treat them, you can pass out and in rare cases, die.
Treatment With Cyclic Antidepressants
Your doctor will likely start you with a low-dose TCA to see how it affects you. You may have to try a few before you find one that works. It can take several weeks to know if it’s helping or for side effects to let up.
Talk to your doctor if you want to stop your medication. Stopping suddenly can cause side effects. They include:
- Irritability or anxiety
- Nausea
- Sweating
- Flu-like symptoms, such as chills and muscle aches
- Trouble sleeping
- Low energy
- Headache
To help you stop your TCA safely, your doctor will slowly wean you off the medication.