Equivalent Dosing of Paliperidone and Risperidone
150 mg of paliperidone is equivalent to 6 mg of risperidone. 1
Conversion Rationale
The conversion between paliperidone and risperidone follows a specific ratio based on pharmacokinetic principles:
- Paliperidone (9-hydroxyrisperidone) is the active metabolite of risperidone 2
- A 25-fold conversion factor exists between oral risperidone and paliperidone palmitate 1-month formulation 1
- Based on pharmacokinetic simulation studies, the following equivalence has been established:
Clinical Considerations
Pharmacological Differences
- Risperidone is metabolized by CYP2D6 to paliperidone, while paliperidone undergoes minimal hepatic metabolism 3
- Paliperidone is primarily eliminated unchanged through the kidneys 3
- The concentration-to-dose (C/D) ratio for oral risperidone is approximately 7 ng/ml per mg/day 3
- The C/D ratio for oral paliperidone is around 4.1 ng/ml per mg/day 3
Dosing Adjustments
- Patients with renal impairment may require dose adjustments when switching between these medications 3
- CYP2D6 polymorphisms can affect risperidone metabolism but have less impact on paliperidone 3
- Drug-drug interactions affecting CYP2D6 will impact risperidone but have minimal effect on paliperidone 3
Cost Implications
When considering a switch between these medications, note that:
- Paliperidone is considerably more expensive than risperidone 2
- Studies have shown potential cost savings of approximately $169 per patient when converting from paliperidone to risperidone 2
Monitoring Recommendations
When switching between these medications:
- Monitor for extrapyramidal symptoms, which may differ between the two medications 4
- Assess sleep patterns, as sedation profiles may vary 4
- Consider a gradual transition to minimize withdrawal or rebound symptoms 4
Remember that while these medications are pharmacologically related, individual patient responses may vary, and the conversion ratio provides a general guideline for dosing equivalence.