What is a recommended cough suppressant for an adult?

Recommended Cough Suppressants for Adults

Dextromethorphan is the recommended first-line cough suppressant for adults due to its superior safety profile compared to opioid alternatives, with optimal dosing at 60 mg for maximum cough reflex suppression. 1

First-Line Treatment Options

• Simple home remedies like honey and lemon should be considered first for benign viral cough as they may be as effective as pharmacological treatments 2, 1
• Dextromethorphan is an FDA-approved cough suppressant that has overtaken codeine as the most widely used antitussive due to its availability, efficacy, and safety profile at directed doses 3, 4
• Standard over-the-counter dosing of dextromethorphan is often subtherapeutic; maximum cough reflex suppression occurs at 60 mg and can be prolonged 1
• Menthol by inhalation provides acute but short-lived cough suppression and can be prescribed as menthol crystals or proprietary capsules 2
• First-generation sedative antihistamines can suppress cough but cause drowsiness, making them particularly suitable for nocturnal cough 1

Treatment Algorithm

1. Start with non-pharmacological approaches:

   • Honey and lemon mixtures 2
   • Voluntary cough suppression techniques (central modulation through voluntary cough suppression may be sufficient to reduce cough frequency) 1

2. If additional relief is needed, use pharmacological options:

   • Dextromethorphan at 60 mg for optimal cough suppression 1
   • For nighttime cough disrupting sleep, consider first-generation antihistamines with sedative properties 2
   • For quick but temporary relief, try menthol inhalation 2

3. Avoid:

   • Codeine-containing products which have no efficacy advantage over dextromethorphan but have increased side effects including drowsiness, nausea, constipation, and potential for physical dependence 1, 4

Evidence Strength and Considerations

• Dextromethorphan has been shown to be similarly effective to codeine in reducing cough frequency but superior in reducing cough intensity in patients with chronic cough 4
• In objective studies, dextromethorphan significantly increases the threshold for cough reflex sensitivity to citric acid challenge 5
• When comparing 20 mg doses, dextromethorphan was considered the better antitussive by the majority of patients compared to codeine (p < 0.001) 4

Important Cautions and Pitfalls

• Caution with higher doses of dextromethorphan as some combined preparations contain other ingredients like paracetamol 2
• At inappropriately high doses (over 1500 mg/day), dextromethorphan can induce psychosis characterized by delusions, hallucinations, and paranoia 6
• Dextromethorphan is subject to abuse and has been called "the poor man's PCP" due to its psychoactive effects at high doses 6
• There is often a marked placebo effect in cough treatment, with both placebo and active treatments improving subjective symptoms to a similar degree in some studies 5
• Codeine dosing should not exceed 6 doses in 24 hours according to FDA labeling, but it is not recommended as a first-line agent due to its side effect profile 7, 1

Special Situations

• For severe paroxysms of postinfectious cough, consider inhaled ipratropium before central antitussives 1
• For productive cough where clearance of secretions is beneficial, antitussives should be avoided 8
• If pertussis is suspected, macrolide antibiotics are indicated rather than antitussives 1