Related Experiment Video
Updated: Jun 22, 2026

Glaucoma-inducing Procedure in an In Vivo Rat Model and Whole-mount Retina Preparation
Published on: March 12, 2016
Mydriatic and cardiovascular effects of phenylephrine 2.5% versus phenylephrine 10%, both associated with tropicamide
Mario M S Motta1, Jacqueline Coblentz, Bruno F Fernandes
1Federal University of the State of Rio de Janeiro, UNIRIO, Rio de Janeiro, Brazil.
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.
Related Concept Videos
Adrenergic Agonists: Therapeutic Uses
Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
Allergies and anaphylaxis:...
Adrenergic Agonists: Direct-Acting Agents
These agents can be classified...
Direct-Acting Cholinergic Agonists: Pharmacological Actions
Adrenergic Agonists: Mixed-Action Agents
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
Adrenergic Agonists: Therapeutic Classification
Vasopressor or pressor agents: They increase blood pressure and function as cardiac stimulants. Examples include endogenous catecholamines (norepinephrine and dopamine) and synthetic agents (phenylephrine).
Bronchodilators: β2-agonists can relax bronchial muscles and widen airways. They are commonly used for treating obstructive pulmonary...
Antiasthma Drugs: Methylxanthines
Theophylline is thought to inhibit phosphodiesterase enzymes, increasing intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). This rise in cAMP and cGMP concentrations stimulates cardiac function,...