phenylephrine hydrochloride and tropicamide ophthalmic

Action and Spectrum

Actions and Spectrum: 

phenylephrine hydrochloride and tropicamide ophthalmic solution is a combination medication used to dilate the pupil and reduce the pain associated with specific eye exams or procedures. 

phenylephrine hydrochloride is a sympathomimetic drug that works by stimulating the alpha-adrenergic receptors in the smooth muscle of the iris, leading to constriction of the dilator muscle and dilation of the pupil. This effect is achieved by the selective binding of phenylephrine to the alpha-1 receptors in the iris, leading to increased sympathetic activity in the eye and an increase in the constriction of the pupil. 

Tropicamide is an antimuscarinic drug that blocks the muscarinic acetylcholine receptors in the eye. This effect results in the relaxation of the ciliary muscle, which controls the shape of the lens in the eye, leading to pupil dilation. 

The combination of phenylephrine hydrochloride and tropicamide ophthalmic solution produces a synergistic effect, with the phenylephrine hydrochloride causing pupil dilation and the tropicamide helping to maintain the dilation for a more extended period. 

The spectrum of activity of phenylephrine hydrochloride and tropicamide ophthalmic solution is limited to the eye and surrounding tissues. The medication is not intended for systemic use and should not significantly affect other organs or systems in the body. However, some side effects may occur, such as increased heart rate or blood pressure, which may be more likely in individuals with underlying cardiovascular disease. 

Drug Interaction

Adverse Reaction

Frequency not defined 

reduced visual acuity 

superficial punctate keratitis 

mild eye discomfort 

transient blurred vision 

photophobia 

tachycardia 

allergic reactions 

vomiting 

central nervous system disturbances  

dryness of the mouth 

headache 

nausea 

pallor 

muscle rigidity 

Black Box Warning

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Closed-angle glaucoma: phenylephrine hydrochloride and tropicamide ophthalmic solution can cause pupil dilation, increasing intraocular pressure, and worsening closed-angle glaucoma. 
• Cardiovascular disease: phenylephrine hydrochloride can cause an increase in blood pressure and heart rate, which can be dangerous for individuals with underlying cardiovascular disease. 
• Prostatic hypertrophy: tropicamide can cause urinary retention and worsen symptoms in individuals with prostatic hypertrophy. 
• Pregnancy and breast-feeding: The safety of phenylephrine hydrochloride and tropicamide ophthalmic solution has not been established in pregnant or breastfeeding women and should be used only if needed and recommended by a healthcare provider. 
• Children: The medication may be contraindicated in children under a certain age, as determined by the healthcare provider. 

Caution: 

• Hypertension: phenylephrine hydrochloride can cause an increase in blood pressure, which can be dangerous for individuals with underlying hypertension. 
• Diabetes: phenylephrine hydrochloride can cause an increase in blood sugar levels, which can be problematic for individuals with diabetes. 
• Hyperthyroidism: phenylephrine hydrochloride can cause an increase in heart rate and blood pressure, which can worsen symptoms in individuals with hyperthyroidism. 
• Seizure disorders: tropicamide can lower the seizure threshold and may increase the risk of seizures in individuals with a history of seizure disorders. 
• Allergies: Individuals with a history of allergies should be monitored closely for allergic reactions when using phenylephrine hydrochloride and tropicamide ophthalmic solution. 
• Contact lens wearers: The medication may cause irritation or discomfort in individuals who wear contact lenses and should be used with caution in these individuals. 
• Elderly: Elderly individuals may be more sensitive to the effects of the medication and may require lower doses. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.   

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

phenylephrine hydrochloride and tropicamide ophthalmic solution are a combination of medications used in the eye to dilate the pupil and reduce the production of aqueous humor, which can help with specific eye examinations and procedures. 

phenylephrine hydrochloride is a sympathomimetic drug that selectively stimulates alpha-adrenergic receptors in the iris dilator muscle, leading to pupil dilation. It also constricts blood vessels in the eye, which can help to reduce redness and inflammation. 

tropicamide is an antimuscarinic drug that blocks the action of acetylcholine at muscarinic receptors in the iris sphincter muscle, leading to pupil dilation. It also reduces aqueous humor production, which can help lower intraocular pressure. 

When used together, phenylephrine hydrochloride and tropicamide can produce a more complete and sustained pupil dilation than either drug alone. 

Pharmacodynamics: 

• phenylephrine hydrochloride and tropicamide ophthalmic solution have pharmacodynamic effects on pupil size and intraocular pressure. 
• phenylephrine hydrochloride selectively stimulates alpha-adrenergic receptors in the iris dilator muscle, leading to pupil dilation while constricting blood vessels in the eye. This results in an increase in pupil size and a reduction in redness and inflammation. 
• tropicamide blocks the action of acetylcholine at muscarinic receptors in the iris sphincter muscle, leading to pupil dilation and a decrease in aqueous humor production. This can help to lower intraocular pressure. 
• The combination of phenylephrine hydrochloride and tropicamide produces a more complete and sustained pupil dilation than either drug alone, making it useful in specific eye examinations and procedures. 

Pharmacokinetics: 

Absorption 

When administered as eye drops, phenylephrine hydrochloride, and tropicamide are primarily absorbed through the cornea and conjunctiva of the eye and into the bloodstream. The rate and extent of absorption can vary based on the dose and formulation used, as well as individual factors such as tear production and eye health. 

Distribution 

Once absorbed, phenylephrine hydrochloride and tropicamide are distributed throughout the body via the bloodstream. They have a relatively short half-life and are rapidly metabolized, which limits their distribution to the site of action in the eye. 

Metabolism 

phenylephrine hydrochloride and tropicamide are metabolized in the liver and other tissues, primarily by enzymes such as cytochrome P450. The metabolites are generally less active than the parent compounds and are excreted in the urine. 

Elimination and Excretion 

phenylephrine hydrochloride and tropicamide are eliminated from the body primarily via the renal route. The elimination half-life of phenylephrine hydrochloride is approximately 2-3 hours, while the elimination half-life of tropicamide is approximately 2 hours. 

Adminstartion

Administration: 

phenylephrine hydrochloride and tropicamide ophthalmic solution is typically administered as eye drops and should only be used under the direction of a healthcare provider or eye specialist. 

The recommended dose and frequency of administration may vary based on the specific condition being treated and the individual patient’s response to the medication. Typically, 1-2 drops of the solution are instilled into the affected eye(s), and the patient may be instructed to close their eyes briefly to allow for proper absorption. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: phenylephrine hydrochloride and tropicamide ophthalmic 

Why do we use phenylephrine hydrochloride and tropicamide ophthalmic? 

• phenylephrine hydrochloride and tropicamide ophthalmic solution is a combination medication used to dilate the pupil and reduce eye inflammation during specific eye examinations and procedures, such as refraction testing or retinal examination. 
• It may also be used to manage certain eye conditions, such as uveitis (inflammation of the eye’s middle layer) and iritis (inflammation of the iris). 
• The dilating effect of the medication can help the healthcare provider to visualize the internal structures of the eye better and assess any abnormalities or changes.  
• The medication works by relaxing the muscles in the iris and allowing light to enter the eye, which can help improve visual clarity and accuracy during testing.