A fixed-dose combination antitussive and expectorant syrup used for the symptomatic relief of dry, non-productive cough associated with upper respiratory tract infections, common cold, and allergic conditions. Diphenhydramine provides antihistaminic, antitussive, and sedative effects; Ammonium Chloride acts as an expectorant by irritating the gastric mucosa to stimulate respiratory tract secretions; Terpin Hydrate is a centrally-acting antitussive and mild expectorant; Sodium Citrate acts as an alkalizing agent and expectorant to loosen phlegm.
Adult: 10 ml (2 teaspoonfuls) three to four times daily. Maximum: 40 ml per day.
Note: Shake the bottle well before use. Use the measuring cup or spoon provided. Can be taken with or without food. Taking with food may reduce gastric irritation from Ammonium Chloride. Maintain adequate fluid intake to aid expectoration.
The combination works synergistically. Diphenhydramine antagonizes histamine at H1-receptors in the respiratory tract, reducing allergic cough and post-nasal drip. Its central anticholinergic action in the medulla suppresses the cough reflex. Ammonium Chloride produces irritation of the gastric mucosa, leading to a reflex increase in bronchial secretions via the vagus nerve, thinning the mucus (expectorant effect). Terpin Hydrate has a direct depressant effect on the cough center in the medulla oblongata and also stimulates respiratory tract secretions. Sodium Citrate, when absorbed, increases the alkalinity of respiratory tract secretions and blood, making the bronchial mucus less viscous and easier to expectorate.
Pregnancy: Category B (US FDA) for Diphenhydramine; others not classified. Use only if clearly needed and potential benefit justifies potential risk. Avoid in third trimester due to risk of neonatal anticholinergic effects.
Driving: STRONGLY NOT ADVISED. Causes significant drowsiness and impairs cognitive and motor functions. Do not operate machinery.
| Alcohol, Benzodiazepines, Opioids | Potentiation of CNS depression, sedation, and impaired psychomotor performance. | Major |
| MAO Inhibitors (e.g., Phenelzine, Selegiline) | Increased anticholinergic and CNS depressant effects, risk of hypertensive crisis. | Major |
| Other Anticholinergics (e.g., Atropine, Tricyclic Antidepressants) | Additive anticholinergic side effects (dry mouth, constipation, urinary retention). | Moderate |
| CNS Stimulants (e.g., Amphetamines) | Diphenhydramine may counteract their effect. | Moderate |
| Drugs metabolized by CYP2D6 (e.g., Codeine, Metoprolol) | Diphenhydramine may inhibit their metabolism, increasing levels. | Moderate |
| Potassium-Sparing Diuretics, ACE Inhibitors, ARBs | Risk of hyperkalaemia with Sodium Citrate. | Moderate |
| Urinary Alkalinizers (e.g., Acetazolamide) | Additive effect with Sodium Citrate, risk of metabolic alkalosis. | Moderate |
Same composition (Diphenhydramine (12.5mg/5ml) + Ammonium Chloride (125mg/5ml) + Terpin Hydrate (7.5mg/5ml) + Sodium Citrate (55mg/5ml)), different brands: