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Reduction of phenylephrine drop size in infants achieves equal dilation with decreased systemic absorption
M G Lynch1, R H Brown, S M Goode
1Department of Ophthalmology, University of Texas Health Science Center, Dallas 75235.
Insights
Reducing eye drop size for phenylephrine hydrochloride in infants did not affect pupillary dilation but lowered systemic absorption. Smaller drops may offer a better risk-benefit profile for pediatric ophthalmic treatments.
Area of Science:
- Ophthalmology
- Pediatric Pharmacology
- Drug Delivery Systems
Background:
- Topical phenylephrine hydrochloride is used for pupillary dilation in infants.
- Concerns exist regarding systemic absorption and potential adverse effects in neonates and infants.
Purpose of the Study:
- To evaluate the impact of reduced eye drop volume on the efficacy and systemic absorption of 2.5% phenylephrine hydrochloride in neonates and infants.
- To determine if smaller drop sizes can maintain therapeutic effect while minimizing systemic exposure.
Main Methods:
- A comparative study involving neonates and infants receiving either an 8-microL or a 30-microL drop volume of phenylephrine hydrochloride.
- Pupillary dilation was measured at 60 minutes post-instillation.
- Plasma phenylephrine levels were quantified at 10 minutes in a separate infant cohort.
Main Results:
- Mean pupillary dilation was comparable between the 8-microL and 30-microL drop sizes (4.86 mm vs 4.57 mm).
- Systemic absorption was significantly lower with the 8-microL drop volume (mean 0.9 ng/mL) compared to the 30-microL drop volume (mean 1.9 ng/mL) at 10 minutes.
- Reduced drop volume did not compromise the pupillary dilation efficacy.
Conclusions:
- Reducing the eye drop volume of topical phenylephrine hydrochloride in neonates and infants is effective for pupillary dilation.
- Smaller drop volumes lead to decreased systemic absorption, potentially improving the safety profile.
- Optimizing drop size may enhance the risk-benefit ratio for ophthalmic phenylephrine use in pediatric populations.
Abstract:
We studied the effect of reducing eye drop size on the efficacy and systemic absorption of topical 2.5% phenylephrine hydrochloride in neonates and infants. Eleven neonates received an 8-microL drop volume in one eye and a 30-microL drop volume (commercial size) in the fellow eye. Mean pupillary dilation at 60 minutes was equivalent (4.86 mm vs 4.57 mm) for both eyes, respectively. The plasma phenylephrine level was determined for the two drop sizes in a second group of infants. Eight infants received an 8-microL drop volume in both eyes, while nine infants received a 30-microL drop volume in both eyes. The mean phenylephrine level at ten minutes was 0.9 ng/mL for the 8-microL drop group and 1.9 ng/mL for the 30 microL drop group. In neonates and infants, reducing the drop volume of topical phenylephrine may improve the risk-benefit ratio.