Selective Serotonin Reuptake Inhibitors, or SSRIs, are a group of medications used in the treatment of mood disorders. They work in the space between two nerve cells in the brain to block re-absorption of serotonin once it is released. This has the effect of increasing the concentration of serotonin, a brain chemical important in mood development. They all have the same general mechanism of action, but there are some variations in their pharmacology.
Citalopram
Citalopram is available in the generic form, or as the brand name Celexa. It is approved by the Food and Drug Administration, or FDA, for the treatment of depression. It is available in 10, 20 and 40 mg tablets and in solution form. The most common side effect from this SSRI medication is nausea and stomach upset, according to eMedExpert.com. It does not tend to be particularly sedating or activating. There are no significant drug interactions of which to be aware.
Escitalopram
Escitalopram, or Lexapro, is the active portion of the citalopram molecule. Therefore, lower doses have equal efficacy and it comes in 5, 10 and 20 mg tablets and an oral solution for the treatment of major depressive disorder and generalized anxiety disorder. It also has few side effects with nausea being the most common. Interaction with other drugs is generally not a concern, notes "American Family Physician."
Fluoxetine
Fluoxetine was the first SSRI medication approved by the FDA. It is available in doses of 10, 20 and 40 mg, and in a 90 mg capsule taken once per week. This drug is indicated in the treatment of depression, bulimia, panic disorder, obsessive-compulsive disorder and premenstrual dysphoric disorder. It is available as the generic, or by the brand names Prozac or Sarafem. This drug has a higher incidence of sleep disruption and stomach upset than others in this class.
Fluoxetine has a much longer effect in the body than any other SSRI. For this reason, it is less likely to lead to problems upon discontinuation, as it is metabolized more slowly than other SSRIs. However, drug interactions may occur even weeks after stopping the medicine. Particular drug interactions of concern are those that can occur with warfarin, tricyclic antidepressants, carbamazepine and phenytoin.
Paroxetine
Paroxetine, or Paxil, comes in 10, 20, 30 and 40 mg tablets and an oral suspension. A controlled-release formula is also available in 12.5 and 25 mg. It is FDA approved for depression, obsessive-compulsive disorder, panic and social anxiety disorders, generalized anxiety disorder and post-traumatic stress disorder, according to Drugs.com. Paroxetine tends to be more sedating than other SSRIs, and has a slightly higher incidence of sexual side effects, notes "American Family Physician." An interaction with warfarin can cause bleeding in people taking both drugs.
Sertraline
The generic drug sertraline is also available under the brand name Zoloft. Administered for the treatment of depression, obsessive-compulsive disorder, social anxiety, panic, and post-traumatic stress disorders and premenstrual dysphoric disorder, it comes in 25, 50 and 75 mg tablets and a liquid concentrate. "American Family Physician" notes that this SSRI tends to cause more cases of diarrhea, but less insomnia than other drugs in the class. The risk of toxicity is increased in those taking high doses of sertraline with a tricyclic antidepressant drug.
