What prophylactic bowel regimen should be initiated when starting oxycodone?

Prophylactic Bowel Regimen for Oxycodone

Always initiate a prophylactic stimulant laxative immediately when starting oxycodone, specifically senna (2 tablets daily) with or without docusate, titrated to achieve one non-forced bowel movement every 1-2 days. 1

First-Line Prophylaxis

• Start senna 2 tablets every morning as the primary prophylactic agent when initiating oxycodone therapy 1, 2
• Adding docusate (a stool softener) to senna is actually less effective than senna alone, so docusate is optional and not necessary 1, 2
• Alternative first-line option: bisacodyl 5-15 mg daily if senna is not tolerated 2
• Another alternative: polyethylene glycol (PEG) 17 grams in 8 oz water twice daily 1, 2
• Maintain adequate fluid intake to support laxative efficacy 1, 2
• Avoid supplemental fiber (such as psyllium) as it is ineffective for opioid-induced constipation 1, 2

Critical Rationale

• Constipation occurs in up to 80% of patients on opioids and tolerance to this side effect never develops, making prophylaxis essential 1, 2
• The goal is one soft, formed bowel movement every 1-2 days without straining or pain 1, 2
• Titrate the laxative dose upward as the oxycodone dose increases 2

If Constipation Develops Despite Prophylaxis

• Rule out bowel obstruction or fecal impaction before escalating therapy 1, 2
• Increase bisacodyl to 10-15 mg two to three times daily 1, 2
• Add osmotic laxatives: magnesium-based products (magnesium hydroxide or citrate), lactulose, or additional PEG 1, 2
• Consider rectal interventions (bisacodyl or glycerin suppository) if oral agents fail, but avoid in thrombocytopenia or neutropenia 1

For Laxative-Refractory Constipation

• Peripherally acting μ-opioid receptor antagonists (PAMORAs) are effective when constipation is clearly opioid-related 1, 2
• Naldemedine 0.2 mg orally once daily has the strongest evidence 2
• Methylnaltrexone 0.15 mg/kg subcutaneously every other day is an alternative, though access is often limited by insurance 1, 2
• Naloxegol 12.5-25 mg once daily is another option 2
• Consider opioid rotation to fentanyl or methadone, which may have less constipating effects 1, 2

Common Pitfalls to Avoid

• Never delay starting prophylactic laxatives when initiating oxycodone—start them simultaneously 1, 2
• Do not use stool softeners (docusate) alone without a stimulant laxative, as they are ineffective 1, 2
• Always rule out obstruction before adding or increasing stimulant laxatives or PAMORAs 1, 2
• Do not rely on dietary fiber alone to prevent opioid-induced constipation 1, 2