Which is better for treating dry cough, Ascoril (guaifenesin) or Lupitus (antihistamine)?

Treatment of Dry Cough: Antihistamine vs Guaifenesin

For dry cough, first-generation antihistamines (like those in Lupitus) are the appropriate choice, while guaifenesin-containing products (like Ascoril LS) should be avoided as they are designed for productive cough with mucus, not dry cough. 1, 2

Why Antihistamines Work for Dry Cough

First-generation (sedating) antihistamines are effective for dry cough through their anticholinergic properties, not primarily through histamine blockade. 1

• These older antihistamines work by blocking cholinergic receptors in the nasal airways, reducing secretions and cough reflex 1
• The central nervous system penetration of first-generation antihistamines contributes to their cough-suppressing effects through action on H1 histaminergic and/or M1 muscarinic receptors in the CNS 1, 3
• They are particularly useful for nocturnal dry cough that disrupts sleep due to their sedating properties 2

Why Guaifenesin is Wrong for Dry Cough

Guaifenesin is an expectorant designed to loosen mucus and make coughs more productive—the opposite of what you want for dry cough. 4

• Expectorants like guaifenesin are intended for wet cough with mucus production, not dry cough 1, 4
• European guidelines explicitly state that expectorants should NOT be prescribed in acute lower respiratory tract infections in primary care 1
• Evidence for guaifenesin's effectiveness is inconsistent even for productive cough, with multiple studies showing no benefit 1, 5
• Cough suppression is illogical when trying to clear mucus, but guaifenesin aims to increase mucus volume 1

Practical Treatment Algorithm for Dry Cough

Start with non-pharmacological approaches first: 2

• Simple home remedies like honey and lemon may be as effective as medications 2
• Voluntary cough suppression techniques 2

If medication is needed for bothersome dry cough: 1, 2

• Use dextromethorphan 30-60 mg (not the subtherapeutic OTC doses) as first-line pharmacological treatment 1, 2
• Consider first-generation antihistamines, especially for nighttime cough 1, 2
• Menthol inhalation provides quick but temporary relief 2

Critical Pitfall to Avoid

Do not use Ascoril LS or any guaifenesin-containing product for dry cough—this is a fundamental mismatch between the drug's mechanism and the clinical problem. 1, 4

• The studies showing Ascoril's effectiveness 6, 7 specifically evaluated patients with productive cough, breathlessness, and sputum production—not dry cough
• Using an expectorant for dry cough lacks physiological rationale and guideline support 1

Important Caveat

Newer non-sedating antihistamines (like loratadine or terfenadine) are NOT effective for cough because they lack the anticholinergic properties and CNS penetration needed for cough suppression. 1