Usage
Chlorpheniramine Maleate + Naphazoline is prescribed for the temporary relief of redness, itching, and swelling of the eyes due to allergic conjunctivitis caused by allergens such as pollen, ragweed, grass, animal dander, and hair. It is classified as an ophthalmic decongestant and antihistamine combination.
The mechanism of action involves naphazoline constricting blood vessels in the eye to reduce redness and swelling, while chlorpheniramine blocks the action of histamine, a chemical mediator responsible for allergic symptoms like itching and watering.
Alternate Names
This drug combination is often referred to as naphazoline/pheniramine ophthalmic. Brand names include Naphcon-A, Opcon-A, and Visine-A.
How It Works
Pharmacodynamics: Naphazoline, an alpha-adrenergic agonist, acts as a decongestant by stimulating alpha-adrenergic receptors in the blood vessels of the conjunctiva, causing vasoconstriction and reducing eye redness and swelling. Chlorpheniramine, an H1-receptor antagonist, blocks the effects of histamine at H1 receptors, thereby relieving itching and watering.
Pharmacokinetics: After topical ocular administration, naphazoline and chlorpheniramine have minimal systemic absorption. Naphazoline’s metabolism and elimination pathways are not fully characterized. Chlorpheniramine is primarily metabolized in the liver and excreted in the urine.
Dosage
Standard Dosage
Adults: Instill 1 or 2 drops in the affected eye(s) up to 4 times daily.
Children:
- 6 years and older: Instill 1 or 2 drops in the affected eye(s) up to 4 times daily.
- Under 6 years: Not recommended.
Special Cases:
- Elderly Patients: Use with caution. Start with the lowest recommended dose.
- Patients with Renal Impairment: Use with caution. Dose adjustment may be necessary.
- Patients with Hepatic Dysfunction: Use with caution. Dose adjustment may be necessary.
- Patients with Comorbid Conditions: Use with caution in patients with cardiovascular disease, hypertension, hyperthyroidism, diabetes, and glaucoma.
Clinical Use Cases
This medication is specifically indicated for allergic conjunctivitis. Its use in other clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations is not established.
Dosage Adjustments
Dose adjustments may be required based on individual patient response and tolerability. Considerations for renal/hepatic dysfunction, metabolic disorders, or genetic polymorphisms should be taken into account.
Side Effects
Common Side Effects
Burning or stinging sensation in the eyes, blurred vision, dilated pupils, eye discomfort, headache, and increased eye redness or irritation.
Rare but Serious Side Effects
Allergic reactions (e.g., skin rash, itching, hives, swelling of the face, lips, or tongue), eye pain, vision changes, shakiness (tremor), fast/pounding/irregular heartbeat, sweating, weakness, nervousness.
Long-Term Effects
Rebound ocular vasodilation or congestion with prolonged or excessive use.
Adverse Drug Reactions (ADR)
Severe allergic reactions require immediate intervention.
Contraindications
- Narrow-angle glaucoma.
- Hypersensitivity to naphazoline, chlorpheniramine, or any component of the formulation.
Drug Interactions
- Monoamine oxidase inhibitors (MAOIs): Concomitant use can lead to hypertensive crisis.
- Beta-blockers: May decrease the antihypertensive effects of beta-blockers and increase the risk of rebound hypertension.
- Other decongestants: Concurrent use may increase the risk of side effects.
Pregnancy and Breastfeeding
- Pregnancy: Use only if clearly needed. Consult with a physician. Limited data available.
- Breastfeeding: Unknown if excreted in breast milk. Consult with a physician.
Drug Profile Summary
- Mechanism of Action: Naphazoline: alpha-adrenergic agonist (vasoconstriction); Chlorpheniramine: H1-receptor antagonist (antihistamine).
- Side Effects: Burning/stinging, blurred vision, dilated pupils, rebound congestion.
- Contraindications: Narrow-angle glaucoma, hypersensitivity.
- Drug Interactions: MAOIs, beta-blockers, other decongestants.
- Pregnancy & Breastfeeding: Consult with a physician.
- Dosage: 1-2 drops up to 4 times/day.
- Monitoring Parameters: Eye redness, itching, swelling, pupil size, blood pressure.
Popular Combinations
This combination is typically used alone.
Precautions
- Remove contact lenses before use.
- Avoid touching the dropper tip to any surface.
- Use caution in patients with cardiovascular disease, hypertension, hyperthyroidism, or diabetes.
- Limit alcohol consumption as it may exacerbate drowsiness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chlorpheniramine Maleate + Naphazoline?
A: Adults and children 6 years and older: 1-2 drops in the affected eye(s) up to 4 times a day. Children under 6 years: Not recommended.
Q2: How does this combination work to relieve eye allergy symptoms?
A: Naphazoline constricts eye blood vessels to reduce redness and swelling, while chlorpheniramine blocks histamine, relieving itching and watering.
A: No, remove contact lenses before instilling the eye drops. You can reinsert them after 15 minutes.
Q4: Are there any serious side effects I should be aware of?
A: Yes, although rare, serious side effects can occur. Seek immediate medical attention if you experience eye pain, changes in vision, severe allergic reactions, or any cardiovascular symptoms like rapid heart rate or palpitations.
Q5: Can I use this medication if I have glaucoma?
A: No, this medication is contraindicated in narrow-angle glaucoma as it can elevate intraocular pressure.
Q6: Is it safe to use Chlorpheniramine Maleate + Naphazoline during pregnancy or breastfeeding?
A: Limited safety data are available. Consult with a physician before use during pregnancy or breastfeeding.
Q7: What should I do if I experience a burning or stinging sensation after using the eye drops?
A: This is a common side effect. Try closing your eyes for a few minutes after instilling the drops. If the sensation persists or worsens, consult your doctor.
Q8: Can I use this medication with other eye drops?
A: If you are using other ophthalmic medications, wait at least 5 minutes between applications.
Q9: How long can I use Chlorpheniramine Maleate + Naphazoline?
A: Use this medication only for the duration recommended by your physician. Prolonged use can lead to rebound congestion. If symptoms persist, consult your doctor.
