What syrup can be recommended for an adult patient with a dry cough, including common brand names?

Recommended Syrup for Adult Dry Cough

For adults with dry cough, dextromethorphan syrup at 30-60 mg per dose (maximum 120 mg daily) is the recommended first-line pharmacological treatment due to its superior efficacy and safety profile compared to codeine-based alternatives. 1, 2

First-Line Treatment Approach

Before reaching for medication, consider these evidence-based non-pharmacological options:

• Honey and lemon mixture is the simplest, cheapest first-line treatment with documented patient-reported benefit and should be tried initially 1, 2
• Voluntary cough suppression through central modulation may be sufficient to reduce cough frequency in many patients 1, 2

Recommended Pharmacological Agent: Dextromethorphan

Dextromethorphan is the preferred antitussive because it effectively suppresses the cough reflex with minimal side effects 1, 3:

Optimal Dosing

• Standard dose: 10-15 mg three to four times daily 2
• Maximum cough suppression: 60 mg single dose provides optimal effect 1, 2
• Daily maximum: 120 mg per day 2
• Critical pitfall: Most over-the-counter preparations contain subtherapeutic doses (often 10-15 mg), which may be inadequate 1, 2

Common Brand Names

Popular dextromethorphan-containing syrups include 4:

• Robitussin for Dry Coughs
• Delsym (extended-release formulation) 3
• Benylin Dry Coughs
• Meltus Dry Coughs

Important caution: Check combination products carefully, as many contain additional ingredients like acetaminophen or paracetamol that could lead to overdose at higher dextromethorphan doses 1, 2

Alternative Options for Specific Situations

For Nighttime Cough Disrupting Sleep

• First-generation sedating antihistamines (like diphenhydramine or chlorpheniramine) can suppress cough and provide sedation beneficial for nocturnal symptoms 1, 2
• The sedative effect is actually therapeutic in this context 1

For Quick But Temporary Relief

• Menthol inhalation suppresses cough reflex acutely but has short-lived effects 1, 2
• Can be prescribed as menthol crystals or proprietary capsules 1

What NOT to Use

Avoid codeine-based syrups (like codeine/promethazine combinations) because 1, 2:

• Codeine has no greater efficacy than dextromethorphan 1
• Codeine carries a significantly worse side effect profile including drowsiness, nausea, constipation, and risk of physical dependence 1, 2
• Pholcodine similarly offers no advantage over dextromethorphan 1

Red Flags Requiring Medical Evaluation

Seek immediate medical attention if the patient experiences 1:

• Hemoptysis (coughing up blood)
• Increasing breathlessness or tachypnea
• Fever with purulent sputum suggesting serious lung infection
• Cough persisting beyond 3 weeks (requires full diagnostic workup) 2

Practical Treatment Algorithm

1. Start with honey and lemon mixture for 1-2 days 1, 2
2. If inadequate relief, add dextromethorphan 30-60 mg three times daily 1, 2
3. For nighttime cough, consider adding a sedating antihistamine at bedtime 1, 2
4. If no improvement after 3 weeks, discontinue symptomatic treatment and investigate underlying causes 2