Switching | Dosing | References

Pramipexole extended-release (Sifrol ER) tablets have been listed on the Pharmaceutical Benefits Scheme (PBS) for treating Parkinson’s disease from 1 August 2010. Unlike the immediate-release tablets, pramipexole extended-release is not PBS subsidised for restless legs syndrome.

See the updated review Immediate-release pramipexole (Sifrol) and extended-release pramipexole (Sifrol ER) for Parkinson's disease.

In unpublished trials, extended-release pramipexole was more effective than placebo and had similar efficacy to that of immediate-release pramipexole in people with early (n = 539) and advanced Parkinson’s disease (n = 507).^1–3 The adverse event profiles for the immediate- and the extended-release tablets were similar.^1–4

Switching

A single unpublished study investigated the efficacy and safety of an overnight switch from immediate-release to extended-release pramipexole in people with early Parkinson’s disease.^1,5 A successful switch was defined as a less than 15% worsening in the motor score and activities of daily living score on the Unified Parkinson’s Disease Rating Scale (UPDRS) 9 weeks after switching. Most patients — 87 out of 103 patients randomised to the extended-release tablets — were successfully switched. A dose adjustment was not usually required but in some of these 87 patients the dose was increased (n = 12) or decreased (n = 3).¹

Dosing

Extended-release pramipexole is taken once daily. The tablet should not be chewed, broken or crushed. The starting dose is 375 micrograms. Titrate the dose every 5–7 days to 1500 micrograms (1.5 mg) daily. If required, increase the dose by 750 micrograms each week up to a maximum of 4500 micrograms (4.5 mg) daily.¹

Use the same daily dose if switching from the immediate-release to the extended-release product. Monitor patients after switching to ensure that their symptoms remain under control: some patients may need to have their dose adjusted.

References

1. Boehringer Ingelheim Pty Limited. Sifrol product information 16 March 2010. Australia: 2010.
2. Boehringer Ingelheim Pty Limited. A double-blind, double-dummy, placebo-controlled, randomized, three parallel groups study comparing the efficacy, safety and tolerability of pramipexole ER versus placebo and versus pramipexole IR administered orally over a 26-week maintenance phase in patients with early Parkinson’s disease (PD). 2009; 8. http://trials.boehringer-ingelheim.com/res/trial/data/pdf/248.524_U09-1232.pdf (accessed 15 June 2010).
   
3. Boehringer Ingelheim Pty Limited. A double-blind, double-dummy, placebo-controlled, randomized, three parallel groups study comparing the efficacy, safety and tolerability of pramipexole ER versus placebo and versus pramipexole IR administered orally over a 26-week maintenance phase in l-Dopa treated patients with advanced Parkinson’s disease (PD). 2009; 10. http://trials.boehringer-ingelheim.com/res/trial/data/pdf/248.525_U09-1270.pdf (accessed 15 June 2010).
   
4. European Medicines Agency. Assessment report for Sifrol. London: EMEA, 2009. http://www.ema.europa.eu/docs/en_GB/document_library/EPAR_-_Assessment_Report_-_Variation/human/000133/WC500049957.pdf (accessed 17 June 2010).
   
5. Boehringer Ingelheim Pty Limited. A double-blind, randomized, parallel groups study to assess the efficacy, safety and tolerability of switching patients with early Parkinson's disease (PD) from pramipexole IR to pramipexole ER or pramipexole IR, 2008. http://trials.boehringer-ingelheim.com/res/trial/data/pdf/248.636_U08-1964.pdf (accessed 15 June 2010).