Naphazoline

Naphazoline

Clinical data
Trade names	Naphcon-a
AHFS/Drugs.com	Monograph
Routes of administration	Nasal route
ATC code	R01AA08 (WHO) S01GA01 (WHO)
Legal status
Legal status	In general: Over-the-counter (OTC)
Identifiers
IUPAC name 2-(naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole
CAS Number	835-31-4
PubChem CID	4436
IUPHAR/BPS	5509
DrugBank	DB06711
ChemSpider	4283
UNII	H231GF11BV
KEGG	D08253
ChEMBL	ChEMBL761
CompTox Dashboard (EPA)	DTXSID3048449
ECHA InfoCard	100.011.492
Chemical and physical data
Formula	C14H14N2
Molar mass	210.274 g·mol−1
3D model (JSmol)	Interactive image
SMILES N\1=C(\NCC/1)Cc2cccc3c2cccc3
InChI InChI=1S/C14H14N2/c1-2-7-13-11(4-1)5-3-6-12(13)10-14-15-8-9-16-14/h1-7H,8-10H2,(H,15,16) Key:CNIIGCLFLJGOGP-UHFFFAOYSA-N
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Naphazoline is a medicine used as a decongestant. 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 was patented in 1934 and came into medical use in 1942.^[1]

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.

Side effects

A few warnings and contraindications that apply to all naphazoline-containing substances intended for medicinal use are:

• Hypersensitivity to naphazoline
• Patients taking MAO inhibitors can experience a severe hypertensive crisis if given a sympathomimetic drug such as naphazoline HCl
• 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
• 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.
• Extended use may cause rhinitis medicamentosa, a condition of rebound nasal congestion.

A possible association with stroke has been suggested.^[2]

Brand names

It is an active ingredient in several over-the-counter formulations including Rohto, Eucool, Clear Eyes and Naphcon eye drops.^[3]

References