Usage
This ophthalmic solution is prescribed for the temporary relief of redness, itching, burning, and discomfort associated with allergic conjunctivitis and minor eye irritations. It is also used to alleviate dryness of the eye. It falls under the pharmacological classifications of:
- Decongestant: Naphazoline hydrochloride
- Antihistamine: Chlorpheniramine maleate
- Lubricant: Hydroxypropylmethylcellulose
- Antiseptic: Boric acid
The mechanism of action involves:
- Vasoconstriction: Naphazoline constricts the blood vessels in the conjunctiva, reducing redness and swelling.
- Antihistaminic Action: Chlorpheniramine blocks the effects of histamine, reducing itching, tearing, and other allergic manifestations.
- Lubrication: Hydroxypropylmethylcellulose provides a soothing and moisturizing effect, relieving dryness and irritation.
- Antiseptic Effect: Boric acid helps prevent bacterial and fungal infections.
Alternate Names
There is no single international nonproprietary name (INN) for this combination product. It is often referred to by its component names. Some sources also add other ingredients like sodium chloride and zinc sulfate to the mix.
Some brand names under which similar formulations are marketed include: Zoneph Eye Drop, Analar Eye Drop, Redif Eye Drops, Neph-M Eye Drop, Conzol Eye Drop, Allerseal, Kaytears Plus and Zoline Eye Drop. These brands may contain other inactive ingredients as well.
How It Works
Pharmacodynamics:
- Naphazoline: Acts as an alpha-adrenergic agonist, constricting conjunctival blood vessels and reducing eye redness.
- Chlorpheniramine: An H1 receptor antagonist, blocking histamine-mediated responses such as itching, tearing, and inflammation.
- Hydroxypropylmethylcellulose: A viscosity-increasing agent that lubricates the ocular surface.
- Boric Acid: Acts as a weak antiseptic and buffering agent.
Pharmacokinetics:
Topical ocular administration results in limited systemic absorption. Absorption can increase with frequent or prolonged use. Metabolism and elimination pathways are not fully characterized for this specific combination. However:
- Naphazoline is metabolized in the liver and excreted in urine.
- Chlorpheniramine is extensively metabolized in the liver, primarily by CYP450 enzymes, and excreted in urine.
Dosage
Standard Dosage
Adults:
Instill 1-2 drops in the affected eye(s) every 3-4 hours.
Children:
Use in children only if prescribed by a doctor. Dosage needs to be adjusted as per age and weight, typically starting with a lower frequency and/or concentration. Pediatric safety considerations include heightened sensitivity to naphazoline’s systemic effects (e.g., drowsiness, decreased body temperature).
Special Cases:
- Elderly Patients: Start with a lower dose and adjust based on the patient’s response. Monitor closely for potential systemic effects.
- Patients with Renal Impairment: Use with caution. Dosage adjustment may be needed.
- Patients with Hepatic Dysfunction: Use with caution. Dosage adjustment may be needed.
- Patients with Comorbid Conditions (e.g., Cardiovascular Disease, Hypertension, Hyperthyroidism, Diabetes): Use with caution and close monitoring. Naphazoline can cause systemic effects like increased blood pressure and heart rate.
Clinical Use Cases
This medication is not indicated for clinical use cases such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
Dosage adjustments are necessary for patients with renal/hepatic impairment, elderly patients, and patients with comorbid conditions (especially cardiovascular disease and hypertension).
Side Effects
Common Side Effects
- Burning or stinging sensation in the eyes
- Blurred vision
- Eye irritation
- Increased redness of the eye (rebound effect with prolonged use)
Rare but Serious Side Effects
- Systemic effects of naphazoline (e.g., increased blood pressure, palpitations, headache, tremors)
- Allergic reactions (e.g., rash, itching, swelling)
- Angle-closure glaucoma (in predisposed individuals)
Long-Term Effects
- Rebound congestion with prolonged use of naphazoline
Adverse Drug Reactions (ADR)
- Severe allergic reactions (anaphylaxis)
Contraindications
- Hypersensitivity to any component of the medication
- Narrow-angle glaucoma
- Severe cardiovascular disease
- Patients currently on Monoamine oxidase inhibitors (MAOIs)
Drug Interactions
- MAOIs can potentiate the pressor effects of naphazoline
- Anticholinergic medications may exacerbate drying effects
- Other ophthalmic medications should be administered at least 5 minutes apart.
Pregnancy and Breastfeeding
The safety of this combination during pregnancy and breastfeeding has not been definitively established. Use only if clearly needed and under strict medical supervision. Consult a physician for potential risks and alternative options.
Drug Profile Summary
- Mechanism of Action: Naphazoline – vasoconstrictor; Chlorpheniramine – antihistamine; Hydroxypropylmethylcellulose – lubricant; Boric acid – mild antiseptic.
- Side Effects: Burning/stinging, blurred vision, rebound congestion. Rarely: systemic effects (e.g., hypertension, palpitations).
- Contraindications: Hypersensitivity, narrow-angle glaucoma, severe cardiovascular disease. MAOI use.
- Drug Interactions: MAOIs, anticholinergics, other ophthalmic medications.
- Pregnancy & Breastfeeding: Consult a physician; use with caution.
- Dosage: Adults: 1-2 drops in affected eye(s) every 3-4 hours. Children: As directed by a physician.
- Monitoring Parameters: Blood pressure, ocular irritation, pupil size, intraocular pressure.
Popular Combinations
This specific combination itself is a commonly used formulation.
Precautions
- General Precautions: Prescreen for allergies, cardiovascular disease, glaucoma. Avoid contact of dropper tip with any surface. Remove contact lenses before use and wait 15 minutes before reinserting.
- Specific Populations: Use with caution in pregnant/breastfeeding women, children, and the elderly.
- Lifestyle Considerations: Limit or avoid alcohol consumption. Avoid driving or operating machinery immediately after use due to potential blurred vision.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for this combination?
A: The typical adult dosage is 1-2 drops in the affected eye(s) every 3-4 hours. Pediatric and special population dosing should be determined by a physician.
A: No, remove contact lenses before instilling the drops and wait at least 15 minutes before reinserting.
Q3: What are the signs of an allergic reaction?
A: Rash, itching, swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. Seek immediate medical help if you experience these symptoms.
Q4: Can I use this long-term for dry eyes?
A: Prolonged use of naphazoline can lead to rebound congestion, making your eyes even redder. Consult a doctor for appropriate long-term dry eye treatment.
Q5: What should I do if I accidentally overdose?
A: Seek immediate medical attention.
Q6: Can I use this if I have high blood pressure?
A: Use with caution and under close medical supervision as naphazoline can increase blood pressure.
Q7: Are there any interactions with other medications?
A: Yes, potential interactions exist with MAOIs, anticholinergics, and other ophthalmic medications. Inform your doctor about all medications you are taking.
Q8: What should I do if my symptoms worsen or don’t improve?
A: Consult a physician. It is essential to follow the prescribed dosage and duration. If symptoms do not improve or worsen, your doctor may need to re-evaluate your condition or adjust the treatment plan.
Q9: Can pregnant or breastfeeding women use this medication?
A: The safety during pregnancy and breastfeeding is not fully established. Consult a physician before using this medication.
