What is the recommended over‑the‑counter antitussive for an otherwise healthy adult with an acute illness and a bothersome dry cough?

Recommended Over-the-Counter Antitussive for Acute Dry Cough

For an otherwise healthy adult with acute illness and bothersome dry cough, dextromethorphan at 60 mg is the recommended over-the-counter antitussive, though honey and lemon may be equally effective and should be considered first given the benign, self-limiting nature of acute viral cough. 1

Primary Recommendation: Start Simple

The Thorax guidelines emphasize that acute viral cough is almost invariably benign and prescribed treatment can be regarded as unnecessary 1. The simplest and cheapest initial approach is a "home remedy" such as honey and lemon, as patients report benefit from various preparations despite little evidence of specific pharmacological effect 1.

The mechanism may be central modulation of the cough reflex—simple voluntary suppression or the soothing effect of drinks and linctuses can reduce cough frequency 1.

If Pharmacologic Treatment Is Needed

When symptoms are distressing enough to warrant medication:

Dextromethorphan (First-Line OTC Option)

• Dose matters critically: The generally recommended dosage is probably subtherapeutic 1
• Maximum cough reflex suppression occurs at 60 mg and can be prolonged 1
• This non-sedating opiate has been shown to suppress acute cough in meta-analysis 1
• Important caveat: Care must be taken at higher doses since some combined preparations contain other ingredients such as paracetamol 1

Menthol (Alternative OTC Option)

• Menthol by inhalation suppresses the cough reflex 1
• May be prescribed as menthol crystals or proprietary capsules
• Limitation: Cough suppression is acute and short-lived 1

Sedative Antihistamines (For Nocturnal Cough)

• First-generation antihistamines with sedative properties suppress cough but cause drowsiness 1
• May be suitable specifically for nocturnal cough when sleep disruption is the primary concern 1

What to Avoid

Codeine and Pholcodine Are NOT Recommended

These opiate antitussives have no greater efficacy than dextromethorphan but have a much greater adverse side effect profile and are not recommended 1. The ACCP guidelines support codeine use only in chronic bronchitis, not in cough due to upper respiratory infection 2.

Clinical Algorithm

1. First approach: Recommend honey and lemon as home remedy
2. If inadequate relief and daytime cough is bothersome: Dextromethorphan 60 mg (ensure single-ingredient preparation)
3. If nocturnal cough is the primary issue: Consider sedating antihistamine
4. For very brief relief: Menthol inhalation
5. Avoid: Codeine-containing products due to unfavorable risk-benefit ratio

Important Caveats

• The evidence base for acute cough treatment is limited because of the variable and episodic nature of the condition 1
• Most studies showing cough suppression used cough challenge methodologies rather than clinical outcomes 1
• Acute viral cough causes significant morbidity despite being benign, justifying symptomatic treatment when quality of life is impaired 1
• Check combination products carefully—many contain multiple active ingredients that may be unnecessary or contraindicated at higher therapeutic doses 1