Usage
This ophthalmic solution is prescribed for the temporary relief of symptoms associated with allergic conjunctivitis, such as redness, itching, burning, tearing, and swelling. It is also used to alleviate minor eye irritation caused by dust, smoke, wind, sun, and other environmental factors. It combines decongestants, an antihistamine, and cooling agents for synergistic relief. This combination is categorized as a ophthalmic decongestant and antihistamine.
The naphazoline and phenylephrine components act as decongestants, constricting blood vessels in the eye to reduce redness and swelling. Chlorpheniramine maleate is an antihistamine that blocks the effects of histamine, a chemical mediator responsible for allergic symptoms like itching and tearing. Menthol provides a cooling sensation, further soothing irritated eyes.
Alternate Names
While there isn’t a universally recognized international non-proprietary name (INN) for this specific combination, the individual components are well-established. The combination may be referred to by its constituent drug names or using various brand names. Some popular brand names include Ocurest-AH and N-Cool.
How It Works
Pharmacodynamics: Naphazoline and phenylephrine are α-adrenergic agonists, primarily stimulating α1-adrenergic receptors in the ocular blood vessels, causing vasoconstriction. Chlorpheniramine maleate is an H1-receptor antagonist, competitively blocking the binding of histamine to H1 receptors, thereby preventing histamine-mediated vasodilation, capillary permeability, and itching. Menthol acts on cold-sensitive TRPM8 receptors, creating a cooling sensation. Camphor, frequently included in such preparations, similarly activates TRP channels, contributing to the soothing effect.
Pharmacokinetics: After topical ophthalmic administration, absorption is minimal, limiting systemic exposure. However, some systemic absorption may occur, especially with frequent or prolonged use. The liver metabolizes chlorpheniramine, and the metabolites are excreted renally. Naphazoline and phenylephrine undergo limited metabolism and are also primarily excreted in urine. Menthol and camphor are rapidly absorbed and metabolized in the liver, with subsequent renal excretion.
Dosage
Standard Dosage
Adults: Instill 1-2 drops into the affected eye(s) every 4-6 hours as needed.
Children: Use in children under 6 years of age is generally not recommended without consulting a physician. For children 6 years and older, the same dosage as adults can be used, but close monitoring is advised.
Special Cases:
- Elderly Patients: Use with caution due to potential sensitivity to systemic effects, particularly cardiovascular effects of phenylephrine and naphazoline. Monitor blood pressure and intraocular pressure.
- Patients with Renal Impairment: Caution is advised as some systemic absorption may occur, leading to accumulation of metabolites. Monitor renal function.
- Patients with Hepatic Dysfunction: Use with caution due to potential impaired metabolism of chlorpheniramine. Monitor liver function tests.
- Patients with Comorbid Conditions: Use with caution in patients with cardiovascular disease, hypertension, hyperthyroidism, diabetes, and benign prostatic hyperplasia (BPH), as the phenylephrine component can exacerbate these conditions. Close monitoring of relevant parameters is necessary. Patients with narrow-angle glaucoma should avoid this medication.
Clinical Use Cases
The use of this combination in specific clinical settings such as intubation, surgical procedures, mechanical ventilation, and the ICU is not standard practice. While the medication might be used to alleviate temporary eye irritation or dryness associated with these situations, it is crucial to consider the potential risks, especially in critically ill patients.
Dosage Adjustments
Dosage adjustments may be needed based on individual patient response and the presence of comorbid conditions, especially renal or hepatic impairment. Consultation with an ophthalmologist is recommended.
Side Effects
Common Side Effects:
- Burning or stinging sensation in the eyes
- Blurred vision
- Mydriasis (pupil dilation)
- Rebound congestion (with prolonged use)
- Eye irritation
- Watery eyes
- Headache
Rare but Serious Side Effects:
- Angle-closure glaucoma (in susceptible individuals)
- Hypersensitivity reactions (rash, itching, angioedema, anaphylaxis)
- Cardiovascular effects (hypertension, tachycardia, palpitations)
Long-Term Effects:
Prolonged use can lead to rebound congestion, where the nasal passages become more congested than before treatment.
Adverse Drug Reactions (ADR):
Severe allergic reactions require immediate medical attention. Angle-closure glaucoma, though rare, can lead to permanent vision loss if not treated promptly.
Contraindications
- Narrow-angle glaucoma
- Hypersensitivity to any component of the medication
- Patients taking MAO inhibitors (or within 14 days of discontinuing MAOIs)
Drug Interactions
- MAO inhibitors (risk of hypertensive crisis)
- Beta-blockers (may counteract the decongestant effects)
- Tricyclic antidepressants (may enhance pressor response of phenylephrine)
- Other sympathomimetics (e.g., pseudoephedrine; additive effects)
- Antihypertensive medications (may decrease efficacy)
- Alcohol and tobacco (can worsen drowsiness and dizziness)
Pregnancy and Breastfeeding
Safety during pregnancy and breastfeeding has not been definitively established. Use with caution and only if the potential benefits outweigh the risks. Consult with an obstetrician or pediatrician.
Drug Profile Summary
- Mechanism of Action: Decongestant (naphazoline, phenylephrine), antihistamine (chlorpheniramine maleate), and cooling agent (menthol) combination.
- Side Effects: Burning/stinging, blurred vision, mydriasis, rebound congestion, eye irritation.
- Contraindications: Narrow-angle glaucoma, hypersensitivity, MAOI use.
- Drug Interactions: MAOIs, beta-blockers, tricyclic antidepressants, other sympathomimetics, antihypertensives.
- Pregnancy & Breastfeeding: Use with caution; consult a physician.
- Dosage: 1-2 drops in affected eye(s) every 4-6 hours.
- Monitoring Parameters: Intraocular pressure, blood pressure, resolution of symptoms.
Popular Combinations
This combination is commonly formulated as a fixed-dose ophthalmic solution.
Precautions
- General Precautions: Perform a thorough eye examination, including checking for glaucoma, before starting treatment. Do not touch the dropper tip to any surface to avoid contamination.
- Specific Populations: See Special Cases under Dosage and Pregnancy and Breastfeeding.
- Lifestyle Considerations: Advise patients against driving or operating machinery if blurred vision occurs.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chlorpheniramine Maleate + Menthol + Naphazoline + Phenylephrine eye drops?
A: The usual dose is 1-2 drops in the affected eye(s) every 4-6 hours, as needed.
A: Remove contact lenses before using the drops and wait at least 15 minutes before reinserting them.
Q3: How long can I use these eye drops?
A: Use only as directed by your physician. Prolonged use can cause rebound congestion.
Q4: What should I do if my symptoms worsen or don’t improve after a few days?
A: Consult your ophthalmologist immediately.
Q5: Can I use this medication if I am pregnant or breastfeeding?
A: Consult your physician before using this medication if you are pregnant or breastfeeding. The safety of this combination during pregnancy and lactation hasn’t been fully established.
Q6: Can this medication interact with other medications I’m taking?
A: Yes, this combination can interact with several medications, including MAO inhibitors, beta-blockers, tricyclic antidepressants, and other sympathomimetics. Inform your doctor about all other medications you are using.
Q7: What are the serious side effects I should watch out for?
A: Allergic reactions (rash, itching, swelling), angle-closure glaucoma (severe eye pain, blurred vision, nausea, vomiting), and cardiovascular effects (increased heart rate, palpitations, high blood pressure) are rare but serious side effects. Seek immediate medical attention if any of these occur.
Q8: Can children use these eye drops?
A: Generally not recommended for children under 6 years of age without a doctor’s consultation. For children 6 years and older, use the adult dosage with close monitoring.
Q9: What is rebound congestion?
A: Rebound congestion can occur with prolonged use of decongestants like naphazoline and phenylephrine. It causes increased nasal congestion after the medication wears off, leading to a cycle of needing more medication. Follow your doctor’s instructions regarding the duration of use.
