Adult: Available preparations:
Naphazoline HCl 0.25 mg and pheniramine 3 mg per mL of eye drop solution
Naphazoline HCl 0.1 mg and pheniramine 2.2 mg per mL of eye drop solution
Instil 1-2 drops in the affected eye(s) up to 4 times daily.
Patient with CV disease, hypertension, diabetes mellitus, hyperthyroidism, benign prostatic hyperplasia, local infection or injury. Children and elderly. Pregnancy and lactation. Concomitant use with MAOIs.
This drug may cause transient effect on vision, if affected, do not drive or operate machinery. Remove contact lenses prior to administration and reinsert after 15 minutes.
Symptoms (particularly in children): Depression of the CNS with marked reduction in body temperature and bradycardia, excessive sweating, drowsiness, and coma; hypertension followed by hypotension. Management: Symptomatic and supportive treatment.
Increased risk of severe hypertensive crisis with MAOIs. Enhanced therapeutic effect with TCAs.
Description: Naphazoline is an α-adrenergic receptor agonist which causes vasoconstriction by stimulating arterioles of the conjunctiva thus reducing swelling, redness and discomfort.
Pheniramine is an alkylamine derivative which binds to histamine H1 receptors on conjunctival epithelial cells, thereby reducing ocular itching. Onset: Conjunctival vasoconstriction: Within 10 minutes. Duration: Up to 6 hours. Pharmacokinetics: Absorption: Pheniramine: Time to peak plasma concentration: 1-2.5 hours. Metabolism: Pheniramine: Metabolised to N-desmethylpheniramine, and N-didesmethylpheniramine metabolites. Excretion: Pheniramine: Via urine (70-83% as unchanged drug and metabolites). Elimination half-life: 16-19 hours.