APPROACHES

The following two tapering approaches are not absolute rules: they can be adapted to each situation, in particular to lengthen the tapering period (and reduce withdrawal effects). The percentage reduction (from 10 to 25%) may vary depending on the drug, the dosage and the difficulty of withdrawal. The advantage of these methods is that they are progressive, allowing you to gradually assess how you feel and adjust the pace of the reduction accordingly.

In the case of taking several psychiatric drugs, it is recommended to start the reduction of a single drug at a time and to check with the doctor and the pharmacist where to start.

You can use these approaches as a guideline, to reduce the risks associated with the reduction as much as possible, while knowing that you will have to adapt them to your situation.

The GAM Personal Guide provides information on the tapering method known as the 10% method. This suggests reducing the daily dosage by 10% of the initial dosage, in stages of variable duration, depending on the type of drug and the difficulties encountered.

Example of 10% reduction

Step 1: 100mg

Step 2: reduction of 10 mg (or 100 mg - 10%) to 90 mg.

Step 3: reduction of 10 mg to 80 mg.

Step 4: reduction of 10 mg to 70 mg.

Step 5: reduction of 10 mg to 60 mg.

You will find more detailed information, in particular on the division and the distribution of the doses on pages 102 to 106 of the GAM guide.

Another similar reduction approach is also known as the hyperbolic method which consists of a reduction in steps of 10%, but from the last dose.

Example of hyperbolic reduction

Step 1: 100mg

Step 2: reduction of 10 mg (or 100 mg - 10%) to 90 mg.

Step 3: reduction of 9 mg (or 90 mg – 10%) to 81 mg.

Step 4: reduction of 8.1 mg (or 81 mg -10%) to 72.9 mg.

Step 5: reduction of 7.29 mg (or 72.9 mg – 10%) to 65.61 mg.

As can be seen in this example, the dose reduction is less and less significant as the stages progress, in order to reduce the impact of withdrawal as much as possible. This approach builds on recent research by Mark Horowitz.

Horowitz, Mark Abie, Sameer Jauhar, Sridhar Natesan, Robin M. Murray, and David Taylor. 2021. “A Method for Tapering Antipsychotic Treatment That May Minimize the Risk of Relapse.” Schizophrenia Bulletin. must: 10.1093/schbul/sbab017 .

Horowitz, Mark Abie, and David Taylor. 2019. “Tapering of SSRI Treatment to Mitigate Withdrawal Symptoms.” The Lancet Psychiatry 6(6):538-46. must: 10.1016/S2215-0366(19)30032-X .

Community pharmacies and specific dosages

Often, when going through withdrawal, it can be difficult to access the doses of medication that correspond to the desired reduction, whether it is 10% or any other percentage. Indeed, the drugs that can be obtained in pharmacies with a prescription are generally marketed according to predefined dosages by the pharmaceutical companies that manufacture them. For example, sertraline (Zoloft) comes in 25 mg, 50 mg or 100 mg capsules, while olanzapine (Zyprexa) comes in 2.5 mg, 5 mg, 7.5 mg , 10, 15mg or 20mg. If we take the example of a person who is prescribed 100 mg of sertraline and who would like to reduce their medication in steps of 10%, they could have difficulty obtaining corresponding dosages, i.e. 90 mg, 80mg, 70mg, and so on. To meet this difficulty, some pharmacists can prepare more specific dosages called extemporaneous mixtures if requested in the prescription.

More specifically, the Quebec Association of Proprietary Pharmacists (AQPP) defines extemporaneous mixtures as follows:

An extemporaneous mixture is a drug preparation that the pharmacist prepares from the doctor's prescription in order to produce a targeted and very specific therapy for a patient. The pharmacist uses the extemporaneous mixture to manufacture a drug that is not commercially available or out of stock. In general, it is therefore not an alternative to a marketed drug, but rather a preparation that would otherwise not be accessible to the patient at the required dosage or in the pharmaceutical form corresponding to their needs.

Still according to the AQPP:

All pharmacies in Quebec can serve an extemporaneous mixture to their patients, but the preparation is not always made on site. If the pharmacy does not have the specialized equipment or the necessary facilities, the pharmacist may have recourse to a pharmacy specializing in these preparations. The preparing pharmacy will then give the extemporaneous mixture to the pharmacist responsible for the patient, who will then give it to their patient.

Reference: https://www.monpharmacien.ca/nouvelles/les-preparations-magistrales-a-quoi-ca-sert/