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Most antidepressants are believed to work by slowing the removal of certain chemicals from the brain. These chemicals are called neurotransmitters. Neurotransmitters are needed for normal brain function. Anti-depressants help people with depression by making these natural chemicals more available to the brain.
How long will I have to take an anti-depressant?
Anti-depressants are typically taken for at least 6 months. In some cases, however, patients and their doctors may decide that anti-depressants are needed for a longer time.
Do anti-depressants have side effects?
Like most medicines, antidepressant drugs can cause side effects. Not all people get these side effects. Any side effects you have will depend on the medicine your doctor has chosen for you. Your doctor will talk to you about your medicine.
What are the different kinds of anti-depressants?
There are many different kinds of anti-depressants, including:
- Selective serotonin reuptake inhibitors (SSRIs)
- Tricyclic antidepressants (tricyclics)
SSRIs are a group of antidepressants that includes drugs such as Citalopram (brand name: Celexa), Fluoxetine (brand name: Prozac), Paroxetine (brand name: Paxil) and Sertraline (brand name: Zoloft). These medicines tend to have fewer side effects than the tricyclics. Some of the side effects that can be caused by SSRIs include dry mouth, nausea, nervousness, insomnia, headache and sexual problems. People taking fluoxetine might also have a feeling of being unable to sit still. People taking paroxetine might feel tired. People taking sertraline might have runny stools and diarrheoa. Please see below for more detailed details on each of these drugs.
Coming off or changing doses on these drugs can be difficult and is now referred to as the SSRI Discontinuation Syndrome and can be very unpleasant with symptoms such as dizziness, light-headedness, vertigo or feeling faint, shock-like sensations, head zapsor paresthesia, anxiety; diarrhoea, fatigue, unsteadiness, headache, insomnia, nausea or vomiting, tremor; and visual disturbances.
The worst discomfort is usually caused by those SSRI's with the shortest half life ie Seroxat and those with the longest half life eg Prozac are the easiest to cope with.
A half life measures how quickly the drug is washed out of your system so Seroxat is washed out within hours whereas Prozac takes several days to clear.
- Fluvoxamine 16 hours
- Paroxetine: 21.0 hours
- Sertraline: 26 hours
- Citalopram: 36 hours
- Fluoxetine: 48-72 hours – 7-15 days
The best way to overcome the discontinuation syndrome is to reduce the dose extremely slowly – usually much slower than your doctor might be advising and only reduce the dose again once you're feeling fine. It is OK to take several months to come off these drugs.
The tricyclics have been used to treat depression for a long time. They include Amitriptyline (brand name: Elavil), Desipramine (brand name: Norpramin), Imipramine (brand name: Tofranil) and Nortriptyline (brand names: Aventyl, Pamelor). Common side effects caused by these medicines include dry mouth, blurred vision, constipation, difficulty urinating, worsening of glaucoma, impaired thinking and tiredness. These antidepressants can also affect a person's blood pressure and heart rate.
Will anti-depressants affect my other medicines?
Anti-depressants can have an effect on many other medicines. If you're going to take an anti-depressant, tell your doctor about all the other medicines you take, including over-the-counter medicines and herbal health products (such as St.John's wort). Ask your doctor and pharmacist if any of your regular medicines can cause problems when combined with an anti-depressant. When taken together, some medicines can cause serious problems.
Taking an MAOI antidepressant at the same time as any other anti-depressants or certain over-the-counter medicines for colds and flu can cause a dangerous reaction. Your doctor will tell you what foods and alcoholic beverages you should avoid while you are taking an MAOI. You should not take an MAOI unless you clearly understand what medications and foods to avoid. If you are taking a MAOI and your doctor wants you to start taking one of the other anti-depressants, he or she will have you stop taking the MAOI for a while before you start the new medicine. This gives the MAOI time to clear out of your body.