Does Bisacodyl Contain Propylene Glycol?
Bisacodyl itself does not inherently contain propylene glycol, but certain bisacodyl formulations—specifically some liquid rectal solutions—do use propylene glycol as a vehicle or solvent.
Formulation-Specific Information
- Durolax solution, a bisacodyl rectal preparation used historically in spinal cord injury management, contains bisacodyl 10 mg dissolved in 5 mL of propylene glycol 1
- This specific formulation was used in the Spinal Injuries Unit at Prince Henry Hospital, Sydney, where 5 mL of the solution (undiluted or diluted with tap water) was administered rectally 1
Standard Bisacodyl Formulations
- Oral tablets and standard suppositories of bisacodyl do not typically contain propylene glycol 2
- Bisacodyl suppositories commonly use either polyethylene glycol base (PGB) or hydrogenated vegetable oil base (HVB) as the vehicle 3
- Research comparing these suppository bases found that PGB-based bisacodyl suppositories significantly reduced bowel care time compared to HVB-based formulations (51.2 minutes vs 102 minutes total bowel care time, P < 0.0005) 3
Clinical Context
- When bisacodyl is used in bowel preparation regimens for colonoscopy, it is typically combined with polyethylene glycol (PEG) solutions, not propylene glycol 2, 4, 5
- The 2-liter PEG plus bisacodyl combination demonstrates equivalent efficacy to 4-liter PEG alone, with significantly better patient tolerability and reduced adverse effects including nausea, vomiting, and bloating 4, 5
Important Caveat
If you are concerned about propylene glycol exposure in a specific patient (such as those with propylene glycol allergy or toxicity risk), you must verify the exact formulation being used, as the vehicle varies by manufacturer and preparation type.