tetryzoline

Action and Spectrum

Actions and spectrum: 

tetryzoline is a sympathomimetic agent that acts as a vasoconstrictor. It acts by narrowing the blood vessels in eyes, which helps to relieve redness and congestion in the eyes.

It is primarily used as a topical decongestant for the eyes and is commonly found in over-the-counter eye drops for this purpose. Its spectrum of action is focused on the eye, where it reduces eye redness and irritation. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Palpitations 

Blurred vision 

mydriasis 

Weakness 

Headache 

Hypertension 

tachycardia 

eye irritation 

sweating 

tremor 

Black Box Warning

Black Box Warning: 

There are no black box warnings associated with the use of tetryzoline. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity: A known or suspected allergy or hypersensitivity to tetryzoline or any of the other ingredients in the eye drop formulation. 
• Narrow-Angle Glaucoma: tetryzoline can potentially increase intraocular pressure, which may be harmful in individuals with narrow-angle glaucoma. It is essential to consult with an eye specialist before using tetryzoline eye drops if you have any form of glaucoma. 
• Severe Cardiovascular Disease: Individuals with severe cardiovascular conditions, such as severe hypertension or coronary artery disease, should use tetryzoline with caution and under medical supervision due to its potential to raise blood pressure. 
• Use of MAO Inhibitors: Monoamine oxidase (MAO) inhibitors, a type of medication used for certain psychiatric and neurological conditions, can interact with tetryzoline. Combining tetryzoline with MAO inhibitors can lead to increased blood pressure and should be avoided.

Caution: 

• Contact Lenses: tetryzoline-containing eye drops may contain preservatives that can be absorbed by the soft contact lenses. It is typically recommended to remove contact lenses before applying the drops and wait at least 15 minutes before reinserting them. 
• Medical Conditions: If you have underlying medical conditions, especially cardiovascular issues like high blood pressure or heart disease, or eye conditions like glaucoma, consult your healthcare provider or eye specialist before using tetryzoline. 
• Pregnancy and Breastfeeding: While tetryzoline eye drops are considered safe during pregnancy and breastfeeding when used as directed, it is advisable to consult a healthcare professional before use, especially if you have concerns. 
• Allergies: If you develop any allergic reactions or adverse effects, such as itching, swelling, or increased redness, discontinue use and consult a healthcare provider.

Comorbidities: 

• Glaucoma: It is a condition characterized by increased intraocular pressure in eye that can damage the optic nerve and lead to vision loss. tetryzoline can potentially increase intraocular pressure, so individuals with glaucoma should use these eye drops only under the guidance of an eye specialist. 
• Dry Eye Syndrome: While tetryzoline can provide temporary relief from redness and irritation, it does not address the underlying causes of dry eye syndrome. Individuals with chronic dry eye may benefit from other types of eyes drops or treatments, and they should consult their eye doctor for appropriate management. 

Pregnancy / Lactation

Pregnancy consideration: pregnancy category: not assigned 

Lactation: excreted into breast milk: 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: 

tetryzoline is a sympathomimetic medication that acts as an alpha-adrenergic agonist. When applied as eye drops, it constricts blood vessels in the eye’s conjunctiva, reducing redness and alleviating eye irritation caused by allergens or minor irritants like dust or smoke. This vasoconstrictive effect is achieved by stimulating alpha-adrenergic receptors on blood vessel walls, causing them to narrow

and reducing blood flow. tetryzoline’s action is short-lived, providing temporary relief from eye redness and discomfort. It is safe when used as directed, but prolonged or excessive use can lead to a phenomenon known as rebound redness, where the redness worsens after the medication wears off. Therefore, tetryzoline eye drops should be used sparingly and as needed.  

Pharmacodynamics: 

• Vasoconstriction: tetryzoline activates alpha-adrenergic receptors in blood vessels on the surface of the eye. This stimulation causes these blood vessels to constrict or narrow. As a result, there is a reduction in blood flow to the eye’s conjunctiva, which leads to decreased redness and swelling of the eye. 
• Reduction of Conjunctival Edema: By constricting blood vessels and reducing fluid leakage from them, tetryzoline helps in reducing the edema of the conjunctiva, which often occurs due to various irritants. 
• Symptomatic Relief: tetryzoline’s vasoconstrictive effect provides temporary relief from symptoms like eye redness, itching, and irritation caused by allergens or minor eye irritants. It does not treat the underlying cause of the symptoms but provides rapid relief. 
• Pupil Dilation: In addition to its primary action, tetryzoline may cause pupil dilation due to its alpha-adrenergic activity. This effect can be useful during eye examinations to better visualize the inside of the eye. 

Pharmacokinetics: 

Absorption 

tetryzoline is applied topically as eye drops or eye solution. When applied to the eye, it is absorbed through the conjunctiva and the cornea. Absorption into the bloodstream is minimal because the drug is intended for local action. 

Distribution 

tetryzoline does not distribute widely throughout the body like systemic drugs. Instead, it stays in and around the eye tissues where it is applied. Some absorption into systemic circulation can occur, but it is typically minimal. 

Metabolism 

tetryzoline is not significantly metabolized by the liver or other organs because its primary site of action is the eye. It acts locally on alpha-adrenergic receptors in the eye tissues to constrict blood vessels. 

Elimination and excretion 

Any tetryzoline that enters systemic circulation is eventually excreted from the body, primarily through urine. 

Adminstartion

Administration: 

• Wash Your Hands: Start by thoroughly washing your hands with soap and water to ensure they are clean. 
• Prepare the Eye Drops: Remove cap from the eye drop bottle. Tilt your head slightly or lie down if it is more comfortable for you. 
• Create a Pouch: Gently pull down your lower eyelid to create a small pouch between your lower eyelid and your eye. 
• Administer the Drops: Hold the bottle upside down with the tip facing down. Position the tip of the bottle above the eye, directly over the pouch you created. Squeeze to release a drop into pouch. Make sure the tip of the bottle does not touch your eye, eyelid, or any other surface to avoid contamination. 
• Press on the Tear Duct: After administering the drop, use your finger to apply gentle pressure to the inner corner of your eye for about a minute. This helps prevent the medication from entering your bloodstream and reduces the risk of side effects. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: tetryzoline 

Pronounced: (teh-TRY-zoh-leen)  

Why do we use tetryzoline? 

• Eye Allergies: tetryzoline eye drops can provide temporary relief from redness and itchiness caused by allergens like pollen, dust, or pet dander. 
• Eye Irritation: tetryzoline can soothe redness and irritation caused by factors such as smoke, smog, wind, or swimming in chlorinated water. 
• Cold or Flu Symptoms: tetryzoline eye drops can temporarily reduce eye redness caused by cold or flu symptoms like watery eyes. 
• Conjunctivitis: In some cases, tetryzoline eye drops may be recommended by a healthcare provider to help alleviate the redness associated with viral or allergic conjunctivitis. However, these drops do not treat the underlying infection or condition.