What opioid cough suppressants are commonly used for a palliative‑care patient with a dry cough?

Common Opioid Cough Suppressants in Palliative Care

For palliative care patients with dry cough, the most commonly used opioid cough suppressants are pholcodine, hydrocodone, dihydrocodeine, morphine, and codeine, with pholcodine and hydrocodone preferred over codeine due to their superior side effect profiles. 1

First-Line Opioid Options

The American College of Chest Physicians recommends the following hierarchy when opioids are indicated for cough suppression:

Preferred Agents

• Pholcodine at 10 mL four times daily is a preferred first-line opioid due to its favorable side effect profile compared to codeine 1, 2
• Hydrocodone at 5 mg twice daily is equally preferred, with documented efficacy in reducing cough frequency by ≥50% in cancer patients 1, 2, 3
• Dihydrocodeine at 10 mg three times daily is another acceptable first-line option 1

Less Preferred Agent

• Codeine at 30-60 mg four times daily is less preferred despite being the most researched opioid antitussive, because it has a greater side effect burden (drowsiness, nausea, constipation) compared to other opioid derivatives 1, 2

Second-Line Opioid Option

Morphine for Refractory Cases

Morphine should be reserved for cough not suppressed by other opioid derivatives or centrally acting antitussives like dextromethorphan. 1

• Initial dosing: Start with oral morphine 5 mg as a single-dose trial; if effective, transition to 5-10 mg slow-release morphine twice daily 1, 4
• For patients already on morphine: Increase the current dose by 20% to achieve antitussive effect, though this is based on clinical experience rather than formal evidence 1, 4
• Bedtime dosing strategy: A bedtime dose of morphine is particularly useful in palliative patients to suppress nocturnal cough and promote undisturbed sleep 1, 4

Alternative Opioid Formulations

• Diamorphine at 5-10 mg subcutaneously over 24 hours can be used when oral routes are not feasible 1
• Methadone linctus at a single dose of 2 mg (2 mL of 1 mg/mL solution) is available in some countries 1

Critical Dosing Considerations for Palliative Patients

Starting Doses Based on Opioid Exposure

• Opioid-naive patients: Use the lower end of dosing ranges to minimize risk of respiratory depression 2
• Patients already on opioids for pain or breathlessness: The patient's previous opioid exposure will dictate the initial starting dose, and a 20% dose increase may be sufficient 1

Hydrocodone Efficacy Data

In a phase II study of 20 palliative cancer patients, hydrocodone achieved a median 70% improvement in cough frequency (range: 50-90%), with a median effective dose of 10 mg/day (range: 5-30 mg/day), and most patients improved within one day. 3

Common Pitfalls to Avoid

• Avoid using codeine as first-line: Despite its extensive research history, codeine has no greater efficacy than dextromethorphan but carries a worse side effect profile, making other opioids more rational choices 2, 4
• Monitor for respiratory depression: All opioid dose increases carry risks of respiratory depression, particularly in patients with underlying pulmonary disease 2
• Assess aspiration risk: In frail palliative patients, opioids that cause sedation may increase aspiration risk, requiring careful monitoring 1, 5
• Address underlying causes: Avoid using opioids to mask symptoms without addressing potentially treatable underlying causes of cough 2, 4

Availability Considerations

Treatment choice may be dictated primarily by regional availability rather than pharmacologic parameters. 1 Pholcodine and hydrocodone are not available in several countries, which may necessitate using dihydrocodeine or morphine as first-line agents instead.