Medication

No. All the SSRIs and Clomipramine appear to be equally effective for the treatment of OCD. Currently only Fluoxetine (Prozac), Sertraline (Zoloft), Fluvoxamine (Luvox), Paroxetine (Paxil), and Clomipramine (Anafranil) have U.S. Food and Drug Administration (FDA) approval for use in OCD. However, the use of Citalopram (Celexa) and Escitalopram (Lexapro) for OCD is also well supported with data and both medications appear to be just as effective as the other SSRIs. Escitalopram (Lexapro) is approved in Europe for treatment of OCD.

Common Mythology

Despite the above, many psychiatrists and patients mistakenly believe that Fluvoxamine (Luvox) is the most effective SSRI for OCD. This myth began when Fluvoxamine (Luvox) became the first SSRI marketed and advertised as the preferred medication for OCD. Data, however, does not show any superiority of Fluvoxamine over any other SSRI for OCD. Head to head trials found that all the SSRIs had very similar efficacy for OCD.

Given that all SSRIs appear to be equally efficacious, the decision of which SSRI to try is based on multiple factors including: side-effect profiles, drug-drug interactions, an individual’s past response to an SSRI or history of a family member’s response to an SSRI, patient preference, and the half-life of each medication.

Studies have shown that, on average, dosages of SSRIs up to two to three times higher than those typically used for depression and anxiety disorders yield the greatest benefits for OCD.

Response to SSRIs takes longer in OCD than in depression or anxiety disorders. While benefits from SSRIs seem to begin soon after their initiation, the progress often occurs at a slow rate and therefore can take several weeks for it to be apparent to both patient and prescriber. An adequate trial of an SSRI for OCD requires eight to 12 weeks, with at least 6 of those weeks at the moderate to high doses required for effective treatment of OCD (for example, at least 40-60 mg/day of Fluoxetine or Paroxetine, or at least 200-300 mg/day of Fluvoxamine or Sertraline). However,  it is important to point out that further improvement can continue well beyond the 12-week mark.

Note: All too often SSRI trials for OCD are deemed failures despite the fact that the dosage was not high enough and/or the trial was not conducted for long enough to properly determine whether the particular SSRI could be effective for the patient. This is problematic since it often leads to either changing a patient’s medication prematurely to another medication with a more adverse side effect and/or augmenting the patient’s medication with additional medication(s) that could yield more adverse effects.

OCD is a chronic condition, and, like most medications, SSRIs are helpful when you take them but do not appear to have continued positive effects years after treatment is stopped. The relapse rate of those patients who discontinue SSRI treatment is high and, as such, long-term treatment is commonly recommended. For some patients, engaging in exposure and response prevention (ERP) therapy can mitigate the risk of relapse that can follow discontinuation of an SSRI.

While studies vary, approximately 40–60% of patients with OCD will have a clinically significant response to their initial SSRI trial. For those who don’t, the first step is to ensure that the patient has been compliant with the medication (taking it as prescribed, including both at the right dosage and at the right intervals).

It is also important to ensure that the patient does not have other psychiatric or physical conditions that could potentially be responsible for the lack of response to the SSRI.

The two most common strategies employed when an initial SSRI trial at full dose is unsuccessful are:

1. Starting, or increasing the frequency of, Exposure & Response Prevention (ERP).
2. Switching to a different SSRI. This is typically recommended for two reasons: First, despite failure of one SSRI, patients will often have a positive response to the second SSRI, though it appears that this may be 10–20% less likely than the likelihood of response from the first trial. Secondly, SSRIs have a more favorable side-effect profile in comparison with other evidenced-based medication strategies used upon failure of the first SSRI. If one or two SSRI trials fail, the most effective next steps are
   1. Switching from an SSRI to Clomipramine (see below).
   2. Augmenting the SSRI with a second, adjunctive medication.
   3. Switching to a second-line standalone medication.

More on Clomipramine

Clomipramine was the first medication to be found effective for treating OCD, and the first medication FDA-approved for OCD. Clomipramine is not an SSRI, but instead falls into a category known as tricyclic antidepressants (TCAs). Clomipramine is unique among the TCAs since it is a very potent serotonin reuptake inhibitor (SRI).

The question of whether Clomipramine is more effective for OCD than the SSRIs has been thoroughly researched. There does not appear to be substantive evidence to believe that Clomipramine is any more effective than SSRIs for adults with OCD. Head to head trials showed the SSRIs and Clomipramine had equal efficacy for OCD. This fact, along with Clomipramine having a worse side-effect profile than the SSRIs, is the reason that SSRIs are the standard first-line medication treatment for OCD.

Despite not being shown to be more effective than SSRIs, Clomipramine is commonly tried when patients fail trials on one or two SSRIs, as it has been found to be effective in some  patients who don’t respond to SSRIs.

The most common adverse effects seen with Clomipramine are: dry mouth, urinary hesitancy, constipation, weight gain, and sexual dysfunction. More serious adverse effects include cardiac conduction delay and a lowering of the seizure threshold. For these reasons it is important that patients on Clomipramine have their drug levels measured, including both their Clomipramine levels and the levels of its active metabolite Desmethylclomipramine. Electrocardiograms (EKGs) must also be done at regular intervals, to monitor for rare but potential heart rhythm abnormalities.