Comparison of efficacy and tolerance between 1% hydroxyamphetamine plus 0.25% tropicamide (Paremyd) and 0.5% tropicamide combined with 2.5% phenylephrine.

BACKGROUND

Paremyd, consisting of a combination of 1.0 percent hydroxyamphetamine and 0.25 percent tropicamide, is a commercially available eyedrop used clinically for diagnostic mydriasis. This study sought to determine if one drop of Paremyd is equally effective and tolerable as the traditional combination of one drop each of 2.5 percent phenylephrine and 0.5 percent tropicamide.

METHODS

A prospective, double-masked, randomized, cross-over study was conducted in 60 normal volunteers ranging from age 20 to 35 years (mean 24.3 years). Twenty-two subjects (36.7 percent) were male, and 32 subjects (53.3 percent) had brown irides. Pupil diameter, amplitude of accommodation, distance and near visual acuity, and subjective comfort of eyedrop instillation were assessed for 8 hours following drug instillation.

RESULTS

Significantly more subjects (p < 0.05) experienced adverse ocular symptoms with the tropicamide plus phenylephrine (TP) combination than with Paremyd (P). There was no statistically significant (p > 0.05) difference in mydriatic response between TP and P. During the first hour, however, TP and P demonstrated significant (p = 0.001) differences in cycloplegic effect.

CONCLUSIONS

Paremyd appears to be as effective a mydriatic as TP, but with greater comfort on instillation. Paremyd has less effect on accommodation.