A fixed-dose combination oral liquid containing a first-generation alkylamine antihistamine (Chlorpheniramine Maleate) and a direct-acting sympathomimetic amine (Phenylephrine). It is primarily indicated for the symptomatic relief of upper respiratory tract conditions associated with allergic rhinitis and the common cold. The combination provides decongestant and anti-allergic effects, targeting nasal congestion, rhinorrhea, sneezing, and itchy/watery eyes.
Adult: 10 ml (2 teaspoonfuls) every 4 to 6 hours. Do not exceed 40 ml (4 doses) in 24 hours.
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 potential GI upset. Do not use for more than 7 days for cold symptoms or more than a few weeks for allergic rhinitis without medical advice.
The combination works synergistically. Chlorpheniramine competitively antagonizes histamine at the H1-receptor sites, inhibiting the physiological effects of histamine (vasodilation, increased capillary permeability, smooth muscle contraction). Phenylephrine is a selective alpha-1 adrenergic receptor agonist that causes vasoconstriction of the dilated arterioles in the nasal mucosa, reducing tissue hyperemia, edema, and nasal congestion.
Pregnancy: Category C (US FDA). Animal studies show risk, human data inadequate. Use only if potential benefit justifies potential fetal risk. Avoid in first trimester. Phenylephrine may reduce placental blood flow.
Driving: NOT ADVISABLE. Chlorpheniramine causes significant drowsiness and impairs cognitive and motor functions. Do not operate machinery or drive until effect is known.
| Monoamine Oxidase Inhibitors (MAOIs) - e.g., Phenelzine, Tranylcypromine | Risk of severe hypertensive crisis, hyperpyrexia. Contraindicated. | Contraindicated |
| Beta-blockers (e.g., Propranolol) | Unopposed alpha-adrenergic stimulation can lead to severe hypertension and bradycardia. | Major |
| Other CNS Depressants (Alcohol, Benzodiazepines, Opioids, Tricyclic Antidepressants) | Additive CNS depression, increased sedation, impaired psychomotor performance. | Major |
| Anticholinergic drugs (e.g., Atropine, TCAs, Antipsychotics) | Additive anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision). | Moderate |
| Sympathomimetics (e.g., Pseudoephedrine, Decongestants in other cold preps) | Additive cardiovascular effects (hypertension, tachycardia). | Major |
| Digoxin | Phenylephrine may increase risk of cardiac arrhythmias. | Moderate |
| Ergot alkaloids (e.g., Ergotamine) | Increased vasoconstrictive effects, risk of peripheral ischemia. | Major |
| Guanethidine, Reserpine | Decreased antihypertensive effect; paradoxical hypertension possible. | Moderate |