Letters to the Editor
New Dosage-Reduction Regime to Avoid Paroxetine Discontinuation Syndrome
Dear Editor:
The serotonin reuptake inhibitor (SRI) discontinuation syndrome appears soon after an SRI or venlafaxine is stopped or decreased. Its symptoms are dizziness, instability, paraesthesia, nausea, fatigue, chills, anxiety, and insomnia (1), which usually develop within the first 24 hours after dosage reduction. With venlafaxine, symptoms can sometimes occur within the first 6 hours. It is unclear whether this syndrome should be thought of in terms of abstinence, similar to that appearing after withdrawal of other medication (that is, benzodiazepines) or in terms of withdrawal from toxic substances (for example, heroin). This distinction is relevant on clinical and legal grounds, since it could be asserted that a patient who develops the syndrome has become addicted to the drug.
More often reported after withdrawal of paroxetine, the syndrome has raised concern inasmuch as it can become difficult to stop a treatment. Where no controlled-release or liquid forms are marketed, tapering as slowly as possible is the only way to prevent the syndrome; in some cases, currently unavailable dosage forms could be necessary. It is also mandatory to completely inform patients regarding the characteristics of the problem.
We previously proposed a regime to discontinue paroxetine that, even though helpful in diminishing syndrome incidence, did not prove as successful as we had expected (2). More recently, we have tried other strategies that proved more effective, although still not always successful. Therefore, we feel that an even slower dosage reduction should be attempted. If we are to achieve this in countries such as Spain, where only 20-mg tablets are available, manufacturers must produce new forms properly grooved to allow smaller dosages.
Our current method of discontinuing paroxetine in patients on 20-mg daily dosage is to taper it down every 20 days, as follows:
Day 1: 20 mg and 15 mg daily on alternate days
Day 21: 15 mg daily
Day 41: 15 mg and 10 mg daily on alternate days
Day 61: 10 mg daily
Day 81: 10 mg and 5 mg daily on alternate days
Day 101: 5 mg daily
Day 121: 5 mg daily and no medication on alternate days
Day 141: stop medication
Even though it is not coherent with paroxetine’s pharmacocynetic and pharmacodynamic properties, this approach has proved helpful. Nevertheless, it is not always effective, and we are therefore planning to taper off every 30 days instead. However, in the absence of controlled-release or liquid forms, 2.5-mg decrements would be more appropriate.
References
1. Schatzberg AF, Haddad P, Kaplan EM, Lejoyeux M, Rosenbaum JF, Young AH, and others. Serotonin reuptake inhibitor discontinuation syndrome: a hypothetical definition. Discontinuation Consensus Panel. J Clin Psychiatry 1997;58 (Suppl) 7:5–10.
2. Pacheco L, Malo P, Aragües E, Etxebeste M. More cases of paroxetine withdrawal syndrome [letter]. Br J Psychiatry 1996;169:384.
Luis Pacheco Yáñez, MD
Pablo Malo, MD
María Etxebeste, MD
Enrique Aragües, MD
Juan Medrano, MD
Bilbao, Spain
|
