A fixed-dose combination oral liquid containing a first-generation alkylamine antihistamine (Chlorpheniramine Maleate) and a selective alpha-1 adrenergic receptor agonist (Phenylephrine). It is primarily used for the symptomatic relief of upper respiratory tract conditions associated with allergic and inflammatory responses, providing decongestion and reduction of histamine-mediated symptoms.
Adult: 5 ml (1 teaspoonful) every 4-6 hours. Maximum: 4 doses (20 ml) in 24 hours.
Note: Shake the bottle well before use. Use the measuring cup/spoon provided. Can be taken with or without food. Taking with food may reduce GI upset.
Chlorpheniramine competitively antagonizes histamine at the H1-receptor sites, inhibiting histamine-mediated symptoms like vasodilation, increased capillary permeability, and itching. Phenylephrine acts as a direct sympathomimetic agonist on alpha-1 adrenergic receptors in the vascular smooth muscle of the respiratory tract mucosa, causing vasoconstriction, reduced edema, and decreased nasal congestion.
Pregnancy: Category C (US FDA). Animal studies show risk, human data inadequate. Use only if potential benefit justifies potential fetal risk, especially in 3rd trimester (neonatal toxicity). Avoid in first trimester unless absolutely necessary.
Driving: NOT ADVISABLE. Chlorpheniramine can cause significant drowsiness and impair cognitive and motor skills. Do not drive or operate machinery until effect is known.
| Monoamine Oxidase Inhibitors (e.g., Phenelzine, Selegiline) | Risk of severe hypertensive crisis due to potentiation of phenylephrine. | Contraindicated |
| Beta-blockers (e.g., Propranolol) | Unopposed alpha-adrenergic activity can lead to severe hypertension and bradycardia. | Major |
| Other CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Additive sedative effects, impaired psychomotor performance. | Major |
| Anticholinergic drugs (e.g., Atropine, TCAs) | Additive anticholinergic side effects (dry mouth, urinary retention, constipation). | Moderate |
| Sympathomimetics (e.g., Pseudoephedrine, Decongestants) | Additive pressor effects, increasing risk of hypertension and tachycardia. | Major |
| Hypertensive agents (e.g., Methyldopa) | Phenylephrine may antagonize the antihypertensive effect. | Moderate |
Same composition (Chlorpheniramine Maleate (2mg/ml) + Phenylephrine (5mg/ml)), different brands: