Naphazoline
Chemical compound
From Wikipedia, the free encyclopedia
Naphazoline is a medicine used as a decongestant, and a vasoconstrictor added to eye drops to relieve red eye. It has a rapid action in reducing swelling when applied to mucous membranes. It is a sympathomimetic agent with marked alpha adrenergic activity that acts on alpha-receptors in the arterioles of the conjunctiva to produce constriction, resulting in decreased congestion.
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| Trade names | Clear Eyes, Cleari, Naphcon-A, Rohto |
| AHFS/Drugs.com | Monograph |
| Routes of administration | Ophthalmic drug administration, nasal administration |
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| ECHA InfoCard | 100.011.492 |
| Chemical and physical data | |
| Formula | C14H14N2 |
| Molar mass | 210.280 g·mol−1 |
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It was patented in 1934 and came into medical use in 1942.[1]
Medical uses
Nasal administration
Nasal decongestant.[2]
Ophthalmic drug administration
Eye drops (brand names Clear Eyes, and Cleari) narrowing swollen blood vessels (ophthalmic arteries, and ophthalmic veins) to relieve red eye.[2]
Temporary red eye can safely be treated when the cause of the redness is established (e.g. cannabis induced conjunctival vasodilation).[3] However, continuous use is not recommended without knowing an underlying condition.
Side effects
A few warnings and contraindications that apply to all naphazoline-containing substances intended for medicinal use are:
- Hypersensitivity to naphazoline
- Use in infants and children can result in central nervous system depression, leading to coma and marked reduction in body temperature
- Should be used with caution in patients with severe cardiovascular disease including cardiac arrhythmia and in patients with diabetes, especially those with a tendency toward diabetic ketoacidosis
- A possible association with stroke has been suggested.[4]
Nasal administration
- Extended use may cause rhinitis medicamentosa, a condition of rebound nasal congestion.
Ophthalmic drug administration
- Stinging
- Discomfort
- Irritation
- Increased red eyes
- Blurred vision
- Mydriasis
- Punctate keratitis
- Lacrimation (tears)
- Increased intraocular pressure
Contraindications
- Patients taking MAO inhibitors can experience a severe hypertensive crisis if given a sympathomimetic drug such as naphazoline HCl
- Drug interactions can occur with anaesthetics that sensitize the myocardium to sympathomimetics (e.g. cyclopropane or halothane cautiously)
- Exercise caution when applying prior to use of phenylephrine.
Pharmacology
Naphazoline is a mixed α1- and α2-adrenergic receptor agonist.[2]
Chemistry
The non-hydrochloride form of Naphazoline has the molecular formula C14H14N2 and a molar mass of 210.28 g/mol. The HCl salt form has a molar mass of 246.73 g/mol.
Society and culture
It is an active ingredient in several over-the-counter eye drop formulations including Clear Eyes, Rohto Cool, Eucool, and Naphcon-A.[7]
Illicit use
The nasal or ophthalmic form of naphazoline has been abused by heroin or cocaine drug addicts.[8][9] It's used as CNS stimulant and vasoconstrictor to enhance primary drug effects.[9]