Selective Serotonin Reuptake Inhibitors (SSRIs)

Selective serotonin reuptake inhibitors (SSRIs) are often still referred to as new antidepressants or atypical antidepressants because they emerged to replace the older tricyclic antidepressant medications. Tricyclics were in some ways more effective that SSRIs, but carried with them much worse side effects. The following list explains the details of dosage and clinical use for each of the new SSRI antidepressant drugs. It will make clear some of the differences between SSRIs.

What Are SSRIs? How Do SSRIs Work?

SSRIs work by blocking the reuptake of serotonin from the synapse back into the neuron that released it. This allows the serotonin molecules to stay in the active zone for longer, meaning they are more likely to be absorbed. Each time a serotonin molecule is absorbed by the receiving cell, it is interpreted as a sugnal from the previous cell. That signal is then passed on to the next neuron through another release of neurotransmitters to the next cells along the line.

List of SSRIs

Citalopram (brand name: Celexa): The typical dosage for Celexa is 20 mg to begin with, and then a maintenance dose of 40 mg per day. The maximum approved dose is 60 mg per day.

Escitalopram (brand names: Lexapro, Cipralex): The typical dose is 10 mg. Clinical trials have shown the 10 mg dose to be as effective as a 20 mg dose in most cases, with fewer side effects. Lexapro and Cipralex are also helpful for anxiety, and so are frequently prescribed for anxiety disorders.

Paroxetine (brand names: Paxil, Seroxat): Paxil and Seroxat are frequently used to treat panic disorder, OCD, social anxiety disorder, generalized anxiety disorder, and PTSD in addition to depression. In some cases, it can also decrease the frequency of cycling in cases of bipolar disorder. The typical dose is 25 mg per day, but that may be increased to as much as 50 mg per day. This drug is also available in controlled-released capsules, which allows for convenient one-a-day dosing.

Fluoxetine (brand name: Prozac): Prozac is the original SSRI “new antidepressant,” and is still very popular. It is now lso used to treat OCD, bulimia, and panic disorder. This drug has a long half-life, which leads to less withdrawal when medication is stopped. Dosing starts at 20 mg and goes up to a maximum of 40 mg.

Fluvoxamine (brand name: Luvox): This new antidepressant is primarily used in the treatment of OCD, but may also be prescribed for depression. The starting dose is typically 50 mg, titrated up by 50 mg every 4-7 days. If the daily dose is greater than 100 mg, it is generally taken in divided dosages. The dose of Luvox should not exceed 300 mg per day.

Sertraline (Zoloft, Lustral): Zoloft and Lustral are also popular in the treatment of panic disorder, OCD, PTSD, social anxiety disorder, and premenstrual dysphoric disorder. Dosing ranges from 50 to 200 mg per day and should be gradually titrated.

It is very important that patients be aware of drug interactions with selectvie serotonin reuptake inhibitors. For example, the common over-the-counter cough medicine ingredient dextromethorphan should not be taken with SSRIs because it can itself inhibit reuptake of serotonin, causing ill effects including the potentially fatal “serotonin syndrome.” This syndrome has highly unpleasant symptoms including dissociation and derealization, cold sweats, confusion, and anxiety.  Some opioids, such as tramadol (Tramal, Ultram), and pethidine/meperidine can cause similar effects. Always be sure to consult your pharmacist about potential drug interactions before taking an SSRI medication.