Tropicamide + Phenylephrine Hydrochloride
Indications
Therapeutic purpose:
- Inflammatory conditions of the uveal tract.
- May be used in temporary lowering of intraocular pressure in glaucoma.
Diagnostic purpose:
- Retinal photography.
- Refractive errors.
- Fundus examination/photography.
- Slit lamp examination.
Pre-operative use: In order to undergo surgical procedure that requires the visualization of structures behind the iris, such as cataract extraction, vitrectomy and retinal detachment surgery.
Pharmacology
Tropicamide binds to and blocks the receptors in the muscles of the eye (muscarinic receptor M4). Tropicamide acts by blocking the responses of the iris sphincter muscle to the iris and ciliary muscles to cholinergic stimulation, producing dilation of the pupil and paralysis of the ciliary muscle.
Phenylephrine Hydrochloride is a selective alpha-1 agonist, which causes mydriasis without cycloplegia. It tends to reduce intraocular lesion by vasoconstrictor action.
Dosage And Administration
Uveitis: 1-2 drops bid-qid or as required.
Diagnostic purpose/Pre-operative purpose: Instill 1-2 drops in the eye(s) 15-20 minutes before examination. If examination is not conducted within 20–30 minutes, an additional drop may be placed in the eye(s) to prolong the effect.
Interaction
Tropicamide may interfere with the antihypertensive action of carbachol, pilocarpine or ophthalmic cholinesterase inhibitors.
Contraindications
This medication is contraindicated in these following cases
- Patients with hypersensitivity to any of the components and narrow angles or narrow angle glaucoma.
- Low birth weight infants and some elderly adults with severe arteriosclerotic cardiovascular or cerebrovascular disease.
- During intraocular operative procedures when the corneal epithelial barrier has been disturbed.
Side Effects
Elevated IOP (occasionally), stinging, blurred vision, tachycardia, photophobia, headache, parasympathetic stimulation and allergic reactions. Systemic effects include arrhythmias, hypertension and coronary artery spasm.
Pregnancy And Lactation
The safety of this medication during pregnancy or lactation has not been established.
Precautions And Warnings
Caution should be taken when administered with, or upto 21days after administration of monoamine oxidase (MAO) inhibitors as exaggerated adrenergic effects may result.
The possibility of psychotic reactions and behavioral disturbances should be considered in patients who are hypersensitive to anticholinergic drugs.
Use with extreme caution in infants.
Overdose Effects
Excessive use in children and in certain susceptible individuals may produce systemic toxic symptoms.
Therapeutic Class
Preparations for Ophthalmic diagnosis.
Storage Conditions
Keep out of the reach of children. Store in a cool, dry place, away from heat and direct light. Do not use more than 4 weeks after opening.