Management of Gastrointestinal Side Effects from Co-codamol
Add a proton pump inhibitor (PPI) such as omeprazole 20-40 mg daily to suppress the gastrointestinal side effects from co-codamol (codeine plus paracetamol). 1, 2
Primary Recommendation: Proton Pump Inhibitors
PPIs are the most effective gastroprotective agents for opioid-related gastrointestinal symptoms, providing superior tolerability compared to alternatives like misoprostol while effectively reducing gastric acid secretion that contributes to dyspepsia and nausea. 1
Omeprazole 20-40 mg taken once daily before meals is the standard dose for gastroprotection, with the option to increase to 40 mg if symptoms persist. 2
PPIs work by reducing gastric acid production, which helps alleviate the dyspepsia, nausea, and stomach discomfort commonly associated with codeine-containing medications. 1
Alternative Gastroprotective Options
If PPIs are contraindicated or not tolerated:
H2-receptor antagonists (ranitidine 300 mg twice daily or cimetidine 400 mg four times daily) can reduce gastric acid secretion, though they are less effective than PPIs for gastric protection. 1
Misoprostol 200 mcg three times daily provides gastroprotection but causes significantly more gastrointestinal side effects (diarrhea, cramping) than PPIs, making it poorly tolerated. 1
Managing Specific Gastrointestinal Symptoms
For Nausea and Vomiting
Metoclopramide 10 mg taken 30 minutes before meals and at bedtime enhances gastric motility and has antiemetic properties, making it particularly useful for opioid-induced nausea. 1
Prochlorperazine 5-10 mg three times daily or ondansetron 4-8 mg twice daily can be added if nausea persists despite PPI therapy. 1
Consider prophylactic antiemetics if the patient has a history of opioid-induced nausea, rather than waiting for symptoms to develop. 1
For Constipation (Common with Codeine)
Loperamide should NOT be used for codeine-related constipation as it will worsen the problem—codeine itself is constipating through the same opioid mechanism. 1, 3
Instead, prescribe a stimulant laxative (senna 2 tablets at bedtime) with or without a stool softener, or polyethylene glycol (PEG) 17 g daily, as constipation is inevitable with opioid therapy and does not resolve with tolerance. 1
Maintain adequate fluid intake (at least 2 liters daily) and avoid supplemental fiber products like psyllium, which are ineffective for opioid-induced constipation. 1
Critical Pitfalls to Avoid
Do not use loperamide or other antidiarrheal agents if the patient is experiencing diarrhea from co-codamol, as this is uncommon—the more likely scenario is constipation from the codeine component. 1, 3
Do not rely on H2-blockers alone for gastroprotection, as they are significantly less effective than PPIs and do not prevent gastric ulcers as reliably. 1
Avoid misoprostol as first-line therapy due to poor tolerability—it causes diarrhea and abdominal cramping in a high percentage of patients, which may worsen the patient's gastrointestinal complaints. 1
Monitoring and Reassessment
If gastrointestinal symptoms persist despite PPI therapy, reassess whether the adverse reactions are truly from the co-codamol or from another cause (concurrent NSAIDs, H. pylori infection, other medications). 1, 4
Consider switching from codeine to an alternative analgesic if symptoms remain intolerable despite maximal gastroprotective therapy—tramadol or low-dose morphine may be better tolerated. 1
The combination of paracetamol plus codeine causes significantly more gastrointestinal adverse events (nausea, vomiting, constipation) than paracetamol alone, with up to 87% of patients experiencing at least one adverse reaction in studies of chronic use. 5