What dose of morphine (opioid analgesic) will suppress cough?

Morphine Dosing for Cough Suppression

For cough suppression in adults, start with oral morphine 5 mg as a single-dose trial, and if effective, transition to 5-10 mg slow-release morphine twice daily. 1

Initial Dosing Strategy

• Begin with 5 mg oral morphine (immediate-release) as a test dose to assess effectiveness and tolerability before committing to regular dosing 1
• If the single 5 mg dose successfully suppresses cough, advance to 5-10 mg slow-release morphine twice daily for sustained control 1
• For patients already receiving morphine for other indications (such as pain), increase their current dose by 20% to achieve antitussive effect, though this recommendation is based on clinical experience rather than formal evidence 1

Context-Specific Considerations

Palliative Care Setting

• In patients with lung cancer experiencing nonspecific cough in the palliative stage, a bedtime dose of morphine is particularly useful to suppress nocturnal cough and promote undisturbed sleep 1
• Diamorphine 5-10 mg subcutaneously over 24 hours represents an alternative parenteral route when oral administration is not feasible 1

Refractory Cases

• Nebulized morphine has shown effectiveness in case reports for intractable cancer-related cough, starting at 5 mg mixed with 3 mL normal saline, with escalation to 10-15 mg as needed 2
• This route provides direct delivery to lung opioid receptors and may avoid systemic side effects while maintaining efficacy 2

Stepwise Treatment Algorithm

The evidence supports a hierarchical approach rather than starting immediately with morphine:

1. First-line: Trial demulcents (simple linctus, glycerol-based preparations) due to low cost and minimal side effects 1, 3
2. Second-line: If demulcents fail, consider other opioid derivatives before morphine—specifically codeine 30-60 mg four times daily, pholcodine 10 mL four times daily, or hydrocodone 5 mg twice daily 1, 4
3. Third-line: Morphine at the doses specified above when other opioids prove inadequate 1, 3
4. Fourth-line: Peripherally-acting antitussives (levodropropizine 75 mg three times daily, moguisteine 100-200 mg three times daily) for opioid-resistant cough 1
5. Last resort: Nebulized local anesthetics (lidocaine 5 mL of 0.2% three times daily) after careful aspiration risk assessment 1, 3

Critical Caveats

• Morphine carries significant side effect burden including drowsiness, nausea, constipation, and potential for physical dependence, which is why it should be reserved for cases where simpler measures have failed 5, 6
• The evidence quality supporting morphine for cough is generally low methodologically, though clinical experience supports its use in refractory cases 1, 3
• Avoid using morphine to mask symptoms without addressing underlying treatable causes of cough (asthma, gastroesophageal reflux, postnasal drip) 3
• In patients with aspiration concerns, morphine requires particularly careful risk-benefit assessment and vigilant monitoring for respiratory depression 3
• Codeine and pholcodine, despite widespread use, have no greater efficacy than dextromethorphan but carry worse side effect profiles, making morphine a more rational choice when escalating beyond non-opioid options 1