Most antidepressants fall into one of five main categories. Within each of the categories, the individual antidepressants work in a similar way and have similar side-effects. The following list includes most of the commonly prescribed antidepressants and their typical side-effects.
Ask your GP or pharmacist if you have any specific questions about your medication.
For full details on side-effects you should study the information sheet provided with your medication.
Tricyclics were the first antidepressant to be used, and have been in use since the 1950s. This class of drugs includes the following (brand name is in brackets):
- Amitriptyline (Tryptizol)
- Imipramine (Tofranil)
- Clomipramine (Anafranil)
- Lofepramine (Gamanil)
- Nortriptyline (Allegron)
- Dosulepin (Prothiaden)
Common problems with Tricyclics include a dry mouth, constipation, a slight tremor, a more rapid heart beat, sleepiness, and increased appetite.
Men may experience difficulties either getting an erection or delayed ejaculation.
Tricyclics are very dangerous in overdose.
SSRIs (Selective Serotonin Reuptake Inhibitors)
SSRIs are a type of antidepressant marketed in the UK since 1989. They block the re-uptake of serotonin into the nerve cell that released it, thereby prolonging its action. These drugs include (brand name in brackets):
- Fluoxetine (Prozac)
- Paroxetine (Seroxat)
- Citalopram (Cipramil)
- Sertraline (Lustral)
Particularly in the first week or two SSRIs may cause nausea or even sickness and sometimes they may increase feelings of anxiety. They can cause problems with sexual function in both men and women.
Overall the SSRIs are less prone to unpleasant side-effects than the Tricyclics and they are much less dangerous in overdose.
MAOIs (Monoamine Oxidase Inhibitors)
MAOIs are an older type of antidepressant. MAOIs include:
- Phenelzine (Nardil)
- Tranylcypromine (Parnate)
- Moclobemide (Manerix) - a newer “reversible” MAOI that has less stringent dietary restrictions
These are now rarely prescribed because they can cause dangerous increases in blood pressure when taken with cheese, yeast (including beer), red wine and meat that isn’t fresh.
SNRIs (Serotonin and Noradrenaline Reuptake Inhibitors)
These drugs slow the re-uptake of both noradrenaline and serotonin and thus prolong their action.
- Venlafaxine (Efexor) was the first SNRI
- Duloxetine (Cymbalta) is the most recently licensed antidepressant, which was released in Scotland in 2006
Venlafaxine is similar in its side effects to the SSRIs. It should not to be used in the presence of severe heart problems and it can increase blood pressure which should therefore be monitored. It can cause weight gain and some problems with sex.
NASSAs (Noradrenaline and Selective Serotonin Antagonists)
Mirtazapine (Zispin) is similar to the tricylics but has fewer side effects than the older drugs and doesn’t cause problems with sex like the older drugs. It can be quite sedative and can cause weight gain.
- Reboxetine (Edronax) is a Selective Noradrenaline Reuptake Inhibitor (NARI)
- Mianserin and Trazadone (Molipaxin) are related to tricyclics
Until the 1990s, Tricyclics were the most commonly prescribed antidepressants but now the substantial majority of antidepressant prescriptions are for SSRIs.