Naphazoline
Encyclopedia
Naphazoline is the common name for 2-(1-naphthylmethyl)-2-imidazoline hydrochloride. It is a sympathomimetic agent with marked alpha adrenergic
activity. It is a vasoconstrictor with a rapid action in reducing swelling when applied to mucous membrane
. It acts on alpha-receptors in the arterioles of the conjunctiva
to produce constriction, resulting in decreased congestion. It is an active ingredient
in several over-the-counter formulations including Clear Eyes and Naphcon eye drop
s.
It has the molecular formula
C14H14N2.HCl and a molecular weight
of 246.73 g/mol.
A possible association with stroke has been suggested.
transforms into iminoester, and undergoes further heterocyclization into the desired imidazoline
derivative upon reaction with ethylene diamine
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
activity. It is a vasoconstrictor with a rapid action in reducing swelling when applied to mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
. It acts on alpha-receptors in the arterioles of the conjunctiva
Conjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
to produce constriction, resulting in decreased congestion. It is an active ingredient
Active ingredient
An active ingredient is the substance of a pharmaceutical drug or a pharmaceutical ingredient and bulk active in medicine; in pesticide formulations active substance may be used. Some medications and pesticide products may contain more than one active ingredient...
in several over-the-counter formulations including Clear Eyes and Naphcon eye drop
Eye drop
Eye drops are saline-containing drops used as a route to administer medication in the eye. Depending on the condition being treated, they may contain steroids, antihistamines, sympathomimetics, beta receptor blockers, parasympathomimetics, parasympatholytics, prostaglandins, non-steroidal...
s.
It has the molecular formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
C14H14N2.HCl and a molecular weight
Molecular mass
The molecular mass of a substance is the mass of one molecule of that substance, in unified atomic mass unit u...
of 246.73 g/mol.
Warnings and contraindications
A few warnings and contraindications that apply to all naphazoline-containing substances intended for medicinal use are:- Hypersensitivity to naphazoline
- Patients taking MAO inhibitorsMonoamine oxidase inhibitorMonoamine oxidase inhibitors are a class of antidepressant drugs prescribed for the treatment of depression. They are particularly effective in treating atypical depression....
can experience a severe hypertensiveHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
crisis if given a sympathomimetic drug such as naphazoline HCl - Use in infants and children can result in central nervous systemCentral nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
depression, leading to coma and marked reduction in body temperatureThermoregulationThermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different... - Should be used with caution in patients with severe cardiovascular diseaseCardiovascular diseaseHeart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
including cardiac arrythmia and in patients with diabetes, especially those with a tendency toward diabetic ketoacidosisKetoacidosisKetoacidosis is a metabolic state associated with high concentrations of ketone bodies, formed by the breakdown of fatty acids and the deamination of amino acids. The two common ketones produced in humans are acetoacetic acid and β-hydroxybutyrate.... - Drug interactions can occur with anaesthetics that sensitize the myocardium to sympathomimetics (e.g. cyclopropaneCyclopropaneCyclopropane is a cycloalkane molecule with the molecular formula C3H6, consisting of three carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms...
or halothaneHalothaneHalothane is an inhalational general anesthetic. Its IUPAC name is 2-bromo-2-chloro-1,1,1-trifluoroethane. It is the only inhalational anesthetic agent containing a bromine atom; there are several other halogenated anesthesia agents which lack the bromine atom and do contain the fluorine and...
cautiously) - Exercise caution when applying prior to use of phenylephrinePhenylephrinePhenylephrine is a selective α1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure...
. - Extended use may cause rhinitis medicamentosaRhinitis medicamentosaRhinitis medicamentosa is a condition of rebound nasal congestion brought on by extended use of topical decongestants that work by constricting blood vessels in the lining of the nose.-Presentation:This condition typically occurs after 5 to 7 days of use of such medications...
, a condition of reboundRebound effectThe rebound effect, or rebound phenomenon, is the tendency of some medications, when discontinued suddenly, to cause a return of the symptoms it relieved, and that, to a degree stronger than they were before treatment first began...
nasal congestionNasal congestionNasal congestion is the blockage of the nasal passages usually due to membranes lining the nose becoming swollen from inflamed blood vessels. It is also known as nasal blockage, nasal obstruction, blocked nose, stuffy nose, or stuffed up nose.Nasal congestion has many causes and can range from a...
.
A possible association with stroke has been suggested.
Chemistry
Naphazoline, 2-(1-naphthylmethyl)-2-imidazoline, is synthesized from (1-naphthyl)acetonitrile, which upon reaction with ethanolEthanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
transforms into iminoester, and undergoes further heterocyclization into the desired imidazoline
Imidazoline
Imidazoline is a nitrogen-containing heterocycle with formula C3H6N2, derived from imidazole. The ring contains an imine bond, and the carbons at the 4 and 5 positions are singly bonded, rather than doubly bonded for the case of imidazole...
derivative upon reaction with ethylene diamine
Ethylene diamine
Ethylenediamine is the organic compound with the formula C2H42. This colorless liquid with an ammonia-like odor is a strongly basic amine. The liquid fumes upon contact with humid air...
- A. Sonn, (1939).