Conversion : Quetiapine SR to IR

• There is little published evidence to guide clinicians on the best method of switching between quetiapine XL and quetiapine IR tablets. 
• Any switch should be fully discussed with the individual and carer, combined with increased monitoring for adverse events.
• In general a straight swap from once daily to twice daily IR is appropriate1 but may be associated with a slightly higher risk of sedation and postural hypotension following the switch. 
• If sedation and postural hypotension are a concern clinicians may wish to consider giving a larger dose in the evening (see table 1). 
• Although other pharmacokinetic parameters are similar the peak plasma concentration for quetiapine XL = 5-6 hours, while IR = 1 hour.

References:

• Switching from quetiapine XL to quetiapine immediate release. Advice for health professionals. Southern Health, NHS Foundation Trust.