Mydriatic and Cardiovascular Effects of Phenylephrine 2.5% versus Phenylephrine 10%, Both Associated with Tropicamide 1%

Abstract

Background/Aims: To evaluate and compare cardiovascular effects (blood pressure and heart rate) of phenylephrine 2.5% versus phenylephrine 10%, and compare pupil diameter before and after instillation of eyedrops. Methods: A total of 58 patients scheduled for funduscopy were dilated with either phenylephrine 2.5% and tropicamide 1% (group 0, n = 29 patients, 58 eyes) or phenylephrine 10% and tropicamide 1% (group 1, n = 29 patients, 58 eyes). Only one drop per eye of each drug was administered. In both groups, pupil diameter, blood pressure and heart rate were measured before and 40 min after eyedrop instillation. Results: We did not observe significant changes in blood pressure or heart rate. Mean pupil diameter in group 0, before the instillation of eyedrops, was 3.51 mm and, in group 1, 2.66 mm. After medication, mean values were 7.38 mm in group 0 and 7.42 mm in group 1. Mean variation was 3.87 mm in group 0 and 4.76 mm in group 1 (p < 0.001). Conclusion: Our results corroborate the finding that one single drop of either 2.5 or 10% phenylephrine is safe and, when 1% tropicamide is combined, satisfactory pupil dilation is achieved.

Intracameral Mydriatics in Cataract Surgery

“…Higher concentrations, however, (1.5 or 3.0%) give significantly larger pupils. Noticeably, a similar lack of dose-response relationship has been noted by several investigators for topical phenylephrine when comparing 2.5% to 10% (Weiss, Weiss et al 1995;Tanner and Casswell 1996;Motta, Coblentz et al 2009). Applying experimental bioavailability data (Mishima 1981) and assuming an aqueous humor volume of 160 µl (Jonsson, Markstrom et al 2006) and a dose of three 37µl drops (Behndig and Linden 1998), three drops of 2.5 -10% would give intracameral doses of 0.14 and 0.57 mg phenylephrine, respectively, which is in the same range as the four lower concentrations in the dose-response study (0.02 mg -0.73 mg).…”

“…Cardiovascular effects from topical mydriatic substances have been reported by many authors thoughout the years (Fraunfelder and Scafidi 1978;Meyer and Fraunfelder 1980;Fraunfelder and Meyer 1985;Hempel, Senn et al 1999;Motta, Coblentz et al 2009). A rapid absorption of anticholinergic and/or adrenergic substances via the nasal mucosa can render surprisingly high systemic levels of the substance.…”

Hemodynamic Changes Associated with Mydriatic Eye Drop Administration in Anesthetized Pediatric Patients

“…In other studies, a significant transient effect on hypertension has not been seen [5,6]. Furthermore, certain studies indicate the absence of hemodynamic changes with administration of either 2.5 or 10% phenylephrine drops [7].…”

Mydriatic insert and intracameral injections compared with mydriatic eyedrops in cataract surgery: Controlled studies

“…[26][27][28][29] This review focuses on combinations of phenylephrine 2.5% to 10.0% with tropicamide 0.5% to 1.0% or cyclopentolate as these are the most thoroughly studied protocols. [29][30][31][32][33][34][35] Phenylephrine Phenylephrine is a synthetic sympathomimetic agent with a strong and selective affinity for a 1 -receptors. Topical application of phenylephrine to the eye causes dilation of the pupil and arteriolar vasoconstriction.…”