Tetrahydrozoline

Tetrahydrozoline Uses, Dosage, Side Effects, Food Interaction and all others data.

Tetrahydrozoline, also known as tetrahydrozoline, is a derivative of imidazoline with central and peripheral alpha (α)-adrenergic properties. Available since the 1950s, tetryzoline is a selective α1-receptor agonist that is used as an ocular and nasal decongestant. Tetrahydrozoline is found in a wide array of over-the-counter eye drops, including the most common brand, Visine. Tetrahydrozoline is also found in combination products with other lubricants and anti-irritants, such as povidone, polyethylene glycol 400, dextran, and zinc sulfate. It is also used in combination with other drug classes, such as antihistamines, corticosteroids, and glucocorticoids in other countries. Tetrahydrozoline is also found in nasal spray under the trade name Tyzine, which is used for decongestion of nasal and nasopharyngeal mucosa.

As it causes profound sedation in children and adults, tetryzoline is increasingly becoming scrutinized for possible drug overdose and toxicity from accidental ingestion. It has also been misused for non-therapeutic purposes as a causative drug for several cases of drug-facilitated sexual assault.

Tetrahydrozoline is a sympathomimetic amine and an alpha-adrenergic agonist with vasoconstricting and decongestant properties. It works by constricting the smaller arterioles of the nasal passages and conjunctival blood vessels to ameliorate allergic rhinitis, nasal congestion, and ocular irritation. Tetrahydrozoline is known to cross the blood-brain barrier to work on alpha-2 adrenoceptors and imidazole receptors, causing effects like hypotension, bradycardia, analgesia, hypothermia, sedation, and hypnosis.

Tetrahydrozoline
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Tetrahydrozoline
Generic	Tetryzoline
Tetryzoline Other Names	Tetrahydrozoline, Tetrizolina, Tetryzolin, Tetryzolina, Tétryzoline, Tetryzoline, Tetryzolinum
Weight	0.05%
Type	Ophthalmic solution
Formula	C₁₃H₁₆N₂
Weight	Average: 200.285 Monoisotopic: 200.131348523
Protein binding	No information is available.
Groups	Approved
Therapeutic Class
Manufacturer
Available Country	United States
Last Updated:	September 19, 2023 at 7:00 am

Uses

Tetrahydrozoline is an alpha-adrenergic agonist used in the temporary symptomatic relief of discomfort and redness of the eyes due to minor irritations, as well as alleviate nasal congestion.

Tetrahydrozoline is indicated for the temporary relief of discomfort and redness of the eye due to minor eye irritations as monotherapy or in combination with other eye lubricants and anti-irritants.

Tetrahydrozoline is also indicated for decongestion of nasal and nasopharyngeal mucosa.

Tetrahydrozoline is also used to associated treatment for these conditions: Active, Symptomatic Blepharitis, Blepharitis allergic, Blepharoconjunctivitis, Chalazion, Conjunctivitis, Conjunctivitis allergic, Conjunctivitis, Vernal, Corneal Inflammation, Dacryocystitis, Dry Eyes, Episcleritis, Eye allergy, Eye redness, Eye swelling, Eyelid folliculitis, Keratoconjunctivitis, Nasal Congestion, Ocular Inflammation, Ocular Irritation, Pterygium, Red eye, Rhinopharyngitis, Scleritis, Sinusitis, Acute Rhinitis, Bacterial blepharitis, Conjunctival hyperemia, Eye discomfort, Nasal edema, Redness and itching of the eyes, Sensation of burning in the eyes, Subacute Rhinitis, Ocular vasoconstriction

How Tetrahydrozoline works

Adrenergic receptors are G-protein-coupled receptors (GPCR) that regulate vascular tone: stimulation of alpha-1 adrenergic receptors leads to vasoconstriction. Ocular redness and nasal congestion often result from vasodilation of nasal, conjunctival, and corneal capillary blood vessels. Activation of alpha-1 adrenergic receptors have been therefore associated with a reduction of symptoms of ocular irritation and nasal congestion. Tetrahydrozoline is a selective agonist of alpha-1 adrenergic receptors, causing vasoconstriction and alleviating ocular and nasal symptoms.

Toxicity

The Lowest published toxic dose (TDLo) of tetryzoline in children following oral administration is 175 mg/kg. Oral LD₅₀ is 785 mg/kg in rats and 345 mg/kg in mice. Intraperitoneal LD₅₀ is 122 mg/kg in rats and 110 mg/kg in mice. Subcutaneous LD₅₀ is 500 mg/kg in rats.

Overdose following accidental oral ingestion in children may lead to profound sedation, possibly accompanied by profuse sweating, hypotension, and shock. In adults, hypertension, bradycardia, drowsiness, and rebound hypotension may be observed, in addition to a shock-like syndrome with hypotension and bradycardia. In one case, cardiovascular effects persisted for 36 hours after unintentional ingestion of tetrahydrozoline. Profound sedation has occurred in adults following accidental oral ingestion due to poisoning.

Overdose should be managed with supportive treatment, with the patient kept warm. Fluid maintenance therapy may be initiated if necessary. The respiratory rate dropping to 10 or below should be responded with oxygen therapy and respiratory assistance. Blood pressure should be carefully monitored to prevent a hypotensive crisis. There is no known antidote to tetryzoline overdose; however, one case report illustrates the successful use of naloxone in reversing the clinical signs and symptoms of tetryzoline overdose in a child. Naloxone has been used to revere clonidine overdose. The exact mechanism of action of naloxone as an antidote is not fully understood; however, it is understood that clonidine and tetryzoline work to inhibit central sympathetic outflow by activating alpha-2 adrenoceptors and inducing endogenous opiate release, which naloxone works to antagonize.

Food Interaction

No interactions found.

Volume of Distribution

No information is available.

Elimination Route

When consumed orally, tetryzoline is rapidly absorbed from the gastrointestinal tract and can cross the blood-brain barrier. Following ocular administration of 0.05% tetryzoline, C_max ranged from 0.068 to 0.380 ng/mL.