Marion Alva Mesina-Bayana, MD, Milagros H. Arroyo, MD Show TROPICAMIDE and phenylephrine hydrochloride eye drops are widely used for mydriasis in routine ophthalmoscopic examinations and prior to cataract surgery to achieve maximal pupil dilation. METHODOLOGY RESULTS between Group B and Group D (p = .035), with the latter causing a gradual decrease especially noted at 10, 20, and 30 minutes from administration. No significant
difference was seen in the diastolic blood pressures within each group (p = .43) and between the 4 groups (p = .11), as well as in the mean increase or decrease in heart rate within each group (p = .78), and between the 4 groups (p = .42) from baseline to 60 minutes postadministration (Figures 2 and 3). None of the patients had tachycardia or bradycardia in the study. A statistically significant increase in pupillary size (Figure 4) from baseline to 60 minutes postinstillation was seen in all of
the 4 groups (p < .05). Among the 4 drugs, the mean pupillary size also increased significantly (p < .05). Groups A, B, and C all showed quick mydriasis from baseline to the 20th-minute mark then reached DISCUSSION Both did not increase the blood pressure and heart rate. However, this study used only one eye per patient and a different concentration of tropicamide.8 A local study that compared phenylephrine
2.5% drops with and without the use of cotton pack also did not cause an increase in blood pressure and heart rate. This study involved the use of the same concentration of phenylephrine and was not compared with other mydriatic combinations.9 In our study, topical ophthalmic administration of the 4 drugs did not cause a significant increase in mean systolic or diastolic blood pressure and heart rate. One drop of 2.5% solution contains approximately 1.125 mg of phenylephrine. In the average
adult, the lowest amount of phenylephrine to produce a pressor effect is 0.4 mg intravenously and 2 mg subcutaneously. The highest safe dosage is 1.5 mg intravenously and 300 mg subcutaneously.4 Assuming that the entire 1.125 mg is absorbed systemically, it may produce an increase in blood pressure. Although epithelial disruption following topical anesthesia may facilitate absorption of topical eye drops, the amount absorbed systemically depends on the dosage, application route, aqueous or
viscous characteristics, dilution by lacrimation, and increased permeability of hyperemic conjunctival epithelium.10 While certain drugs are rapidly transported from the nasolacrimal system and absorbed into the vascular system, it is possible that a relatively small portion of commercially available phenylephrine is able to do so. This could be because the drug causes local vasoconstriction, there is diminished flow to an area with which it is in contact, or the patient complied well with
instructions not to blink. A drop in systolic blood pressure in all treatment groups was observed. It is possible that this may have occurred as a result of the calming effect of being instructed to sit still with the eyes closed. Rapidity of dilatation saves time for both patient and physician. This study showed all 4 drug groups increased pupillary size, but it was the tropicamide-phenylephrine 0.5%/0.5% and the self- prepared tropicamide 0.25%- phenylephrine 1.25% groups that produced rapid
dilatation and did not have a significant effect on blood pressure. By eliminating the need for multiple instillation of two different drugs, the use of a single eye drop References Acknowledgment What type of medication is used in combination with mydriatics to dilate the patient's pupils?Atropine, cyclopentolate
Mydriatics and cycloplegics cause pupillary dilation and congestion of the anterior chamber angle yielding increased risk for acute angle closure in at-risk patients.
What type of drug is used to dilate the pupil?Mydriatics are a class of drugs that cause pupil dilation. Sometimes called eye dilation drops, they're commonly used during eye exams and surgeries. Stimulants, such as Ritalin and Adderall, are common in the treatment of attention-deficit hyperactivity disorder (ADHD).
What is used with mydriatics?Commonly used mydriatics include adrenergic agonist medications, such as epinephrine and phenylephrine, while some medications that act as both mydriatics and cycloplegics include antimuscarinic medications, such as atropine, cyclopentolate, homatropine, scopolamine, and tropicamide.
Which of the following drugs causes the pupils to contract mydriatics?Drugs that can cause mydriasis include: Stimulants (typically monoaminergics) such as amphetamines, cocaine, MDMA, and mephedrone.
|