Usage
Hypromellose is prescribed for the treatment of dry eye syndrome (keratoconjunctivitis sicca), a condition characterized by insufficient lubrication of the eyes. It is also used during certain ophthalmic procedures like gonioscopy, and to moisten hard contact lenses or lubricate artificial eyes. Hypromellose is classified as an ophthalmic lubricant or artificial tear. It works by mimicking the action of natural tears, providing a protective and moisturizing film over the cornea and conjunctiva. This film helps to alleviate dryness, burning, irritation, and foreign body sensation associated with dry eye conditions.
Alternate Names
Hypromellose is also known as hydroxypropyl methylcellulose (HPMC). Brand names under which hypromellose eye drops are marketed include Tears Naturale, Isopto Tears, GenTeal, Refresh, and Artelac, among others. Different brands may have slightly different formulations and concentrations of hypromellose.
How It Works
Pharmacodynamics: Hypromellose is a viscoelastic polymer that increases the viscosity of the tear film, thereby prolonging tear film breakup time and improving the stability of the tear film. This enhanced lubrication reduces friction between the eyelid and the cornea, alleviating the symptoms of dry eye.
Pharmacokinetics: When administered as eye drops, hypromellose acts locally on the ocular surface. Systemic absorption is negligible, minimizing the risk of systemic side effects. The drug is not metabolized and is eliminated primarily through the tear drainage system.
Mode of Action: Hypromellose does not bind to specific receptors or inhibit enzymes. Its mechanism of action is primarily physical, based on its ability to form a viscous, lubricating film on the ocular surface.
Dosage
Standard Dosage
Adults: Instill 1 or 2 drops of a 0.3% hypromellose solution into the affected eye(s) 3 to 4 times daily, or as needed. Higher concentrations (e.g., 0.5%, 2%) may be used in more severe cases.
Children: Similar to adult dosing. Pediatric safety considerations are minimal due to negligible systemic absorption.
Special Cases:
- Elderly Patients: No dosage adjustment is generally needed.
- Patients with Renal Impairment: No dosage adjustment is necessary.
- Patients with Hepatic Dysfunction: No dosage adjustment is necessary.
- Patients with Comorbid Conditions: Use with caution in patients with glaucoma.
Clinical Use Cases
- Intubation: Hypromellose solutions may be used to lubricate the eyes during intubation to prevent corneal abrasions.
- Surgical Procedures: Hypromellose solutions are used during various ophthalmic surgical procedures (e.g., cataract surgery) to protect and maintain the shape of the eye. Higher concentrations are often used in these settings.
- Mechanical Ventilation: Hypromellose can be used to prevent corneal drying in patients on mechanical ventilation.
- Intensive Care Unit (ICU) Use: Similar to mechanical ventilation, hypromellose can be used to maintain corneal moisture in critically ill patients.
- Emergency Situations: There are no specific emergency uses for hypromellose.
Dosage Adjustments
Dosage adjustments are generally not required based on patient-specific factors due to minimal systemic absorption.
Side Effects
Common Side Effects
- Blurred vision (transient)
- Mild stinging or burning upon instillation
- Foreign body sensation
- Eye irritation
- Eye redness
Rare but Serious Side Effects
Severe allergic reactions (rare).
Long-Term Effects
No long-term adverse effects have been reported.
Adverse Drug Reactions (ADR)
Clinically significant ADRs are rare.
Contraindications
- Hypersensitivity to hypromellose or any of the excipients in the formulation.
Drug Interactions
Hypromellose can prolong the corneal contact time of other ophthalmic medications. Wait 5-15 minutes between instilling different eye drops. Interactions with systemic medications are unlikely due to minimal systemic absorption.
Pregnancy and Breastfeeding
Pregnancy Safety Category: C (ophthalmic use). Use only if clearly needed. Data on excretion in breast milk are limited; however, due to minimal systemic absorption, it is considered safe to use while breastfeeding.
Drug Profile Summary
- Mechanism of Action: Enhances tear viscosity and improves tear film stability.
- Side Effects: Transient blurred vision, stinging, irritation.
- Contraindications: Hypersensitivity.
- Drug Interactions: May prolong corneal contact time of other ophthalmic drugs.
- Pregnancy & Breastfeeding: Generally safe.
- Dosage: 1-2 drops 3-4 times/day, or as needed.
- Monitoring Parameters: Observe for signs of eye irritation or allergic reactions.
Popular Combinations
Hypromellose is often used in combination with other ophthalmic medications, such as artificial tears containing lipids or other demulcents, to address different aspects of dry eye disease.
Precautions
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General Precautions: Advise patients to avoid touching the tip of the dropper bottle to any surface to prevent contamination. If using soft contact lenses, remove them before instilling the drops and wait 15 minutes before reinserting. Some formulations contain benzalkonium chloride as a preservative, which can be absorbed by soft contact lenses and cause discoloration or irritation.
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Specific Populations: Use cautiously in dry eye patients with compromised corneal integrity.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Hypromellose?
A: The standard recommended dosage is 1-2 drops of 0.3% hypromellose solution in the affected eye(s) three to four times daily or as needed.
A: Remove soft contact lenses before instilling hypromellose drops containing benzalkonium chloride and wait 15 minutes before reinserting.
Q3: What are the common side effects of Hypromellose?
A: Common side effects include transient blurred vision, mild stinging, foreign body sensation, and eye irritation.
Q4: Is Hypromellose safe during pregnancy and breastfeeding?
A: Generally considered safe, but use only if clearly needed.
Q5: How does Hypromellose work to treat dry eye?
A: Hypromellose increases tear film viscosity and improves tear stability, reducing friction and irritation.
Q6: Are there any contraindications to using Hypromellose?
A: The main contraindication is hypersensitivity to hypromellose or any components of the formulation.
Q7: Can Hypromellose be used in children?
A: Yes, similar dosing guidelines as for adults.
Q8: How should Hypromellose be stored?
A: Store at room temperature, away from heat, moisture, and direct light.
Q9: What should patients do if their symptoms worsen or persist despite using Hypromellose?
A: Patients should discontinue use and consult their ophthalmologist.
