Eyedrop‐Induced Allergy: Clinical Evaluation and Diagnostic Protocol

Ophthalmic preservatives: focus on polyquaternium-1

INTRODUCTION

Ophthalmic preservatives, such as polyquaternium-1 (PQ-1), are critical for the inhibition of growth of microbial contaminants in multi-dose bottles of topical medications. These antimicrobial agents must have a high efficacy against pathogenic organisms, while maintaining a favorable tolerability and safety profile.

AREAS COVERED

This review focuses on the ophthalmic preservative PQ-1. For comparison purposes, the most commonly used preservative, benzalkonium chloride (BAK), is also discussed. This survey focuses primarily on data collected during the past 10 years.

EXPERT OPINION

Effective drug delivery requires more than just an active ingredient that achieves its desired biological effect on end-target tissues. In addition, drugs must be stable in the containers that they are stored in, and must possess minimal undesired local and systemic side effects that can cause patients to decrease their adherence. In addressing these concerns, specifically in topical ophthalmic drops, one must take into account the active ingredients, vehicle components and preservatives. Medications with fewer adverse effects may lead to enhanced adherence to therapy; therefore, the induction of such adverse outcomes must be considered by physicians when treating patients with chronic ocular disease. Although BAK will continue to be used in ophthalmic medications, due to its familiarity and compatibility with a broad range of topical ocular formulations, PQ-1 is certainly a viable alternative in the preservative formulary armamentarium.

Early resolution of convergence spasms following the addition of antipsychotic medications

We report a case of early resolution of convergence spasms following the addition of antipsychotic medications and present it as a possible alternative to the conventional treatment for convergence spasms. The cessation of atropinization of the eyes and the use of reading glasses was achieved after only 2 months following the initiation of antipsychotic medications for childhood emotional disorder.

Allergic contact blepheroconjunctivitis with phenylephrine eyedrops--the relevance of late readings of intradermal tests

Allergic reactions to midriatic eyedrops are rare despite extensively used by ophthalmologists. Phenylephrine is responsible for 54-95% of cases reported in literature. We present the case of a 56-year-old man with blepharoconjunctivitis after instillation of phenylephrine 5%, tropicamide 0.5%, oxibuprocaine eyedrops. The patient reported good tolerance to the mentioned drugs. Immediate readings of prick and intradermal tests, performed with the suspected drugs, were negative. Late readings (48 and 72 hours) of epicutaneous tests were also negative. At 72 hours, prick and intradermal tests to phenylephrine were positive. Allergic blepharoconjunctivitis to phenylephrine was diagnosed. Phenylephrine is an extensively used midriatic that can act as a potent sensitizing agent and can be the cause of allergic contact reactions in exposed patients. With this case we illustrate the relevance of late readings of intradermal tests in the diagnosis of late hypersensitivity drug reactions. The authors discuss about possible mechanisms responsible for negative results of epicutaneous tests.