Pemirolast

Class: Antiallergic Agents
VA Class: OP300
Chemical Name: 9-Methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2a]pyrimidin-4-one potassium salt
Molecular Formula: C₁₀H₇KN₆O
CAS Number: 100299-08-9
Brands: Alamast

Medically reviewed by Drugs.com. Last updated on Aug 24, 2020.

• Overview
• Side Effects
• Dosage
• Professional
• Pregnancy
• More

Introduction

Mast-cell stabilizer.¹

Uses for Pemirolast

Allergic Conjunctivitis

Prevention of ocular itching associated with allergic conjunctivitis.¹

Pemirolast Dosage and Administration

Administration

Ophthalmic Administration

Apply topically to the eye as an ophthalmic solution.¹ Not for injection or oral use.¹

Avoid contamination of the solution container.¹

Dosage

Available as pemirolast potassium; dosage expressed in terms of the salt.¹

Initiate therapy before and continue throughout pollen season.^{4 5 6 7}

Pediatric Patients

Allergic Conjunctivitis

Ophthalmic

Children ≥3 years of age: 1 or 2 drops of a 0.1% solution in the affected eye(s) 4 times daily.¹

Symptomatic response (i.e., decreased itching) may be evident within a few days following initiation but frequently requires up to 4 weeks of therapy.^{1 2 3}

Adults

Allergic Conjunctivitis

Ophthalmic

1 or 2 drops of a 0.1% solution in the affected eye(s) 4 times daily.¹

Symptomatic response (i.e., decreased itching) may be evident within a few days following initiation but frequently requires up to 4 weeks of therapy.^{1 2 3}

Cautions for Pemirolast

Contraindications

• Known hypersensitivity to pemirolast or any ingredient in the formulation.¹

Warnings/Precautions

Specific Populations

Pregnancy

Category C.¹

Lactation

Distributed into milk in rats; not known whether distributed into human milk.¹ Caution if used in nursing women.¹

Pediatric Use

Safety and efficacy not established in children <3 years of age.¹

Common Adverse Effects

Headache, rhinitis, cold/flu symptoms.¹

Interactions for Pemirolast

No formal drug interaction studies to date.⁸

Pemirolast Pharmacokinetics

Absorption

Bioavailability

Following topical application to both eyes (0.1% solution 4 times daily for 2 weeks), peak plasma concentrations were attained within about 25 minutes, but were substantially lower than those following a single (10 mg) oral dose.¹

Elimination

Elimination Route

10–15% of topical ophthalmic dose excreted unchanged in urine.¹

Half-life

About 4.5 hours.¹

Stability

Storage

Ophthalmic

Solution

15–25°C.¹

Actions

• Suppresses the release of mediators from cells involved in hypersensitivity reactions, including mast cells, and decreases chemotaxis and activation of eosinophils.¹

• Reportedly blocks calcium channels in mast cell membranes.¹

Advice to Patients

• Importance of learning and adhering to proper administration techniques to avoid contamination of the product.¹

• Importance of removing soft contact lenses prior to administration of each dose.¹ Delay reinsertion for 10 minutes after administration if eyes are not red; do not wear contact lenses if eye(s) are red.¹ Not indicated for contact lens-related irritation.¹

• Importance of reporting any worsening of symptoms or new-onset ocular pain/discomfort.⁸

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.¹

• Importance of informing patients of other important precautionary information.¹ (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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