Methazolamide

Not to be confused with methimazole, metamizole, or acetazolamide.

Methazolamide (trade name Neptazane) is a potent carbonic anhydrase inhibitor. It is indicated in the treatment of increased intraocular pressure (IOP) in chronic open-angle glaucoma and secondary glaucoma. Also it is used preoperatively in acute angle-closure (narrow-angle) glaucoma where lowering the IOP is desired before surgery.

Methazolamide

Clinical data
Other names	N-(3-Methyl-5-sulfamoyl-3H-1,3,4-thiadiazol-2-ylidene) ethanamide
AHFS/Drugs.com	Monograph
MedlinePlus	a601233
Routes of administration	Oral
ATC code	S01EC05 (WHO)
Legal status
Legal status	US: ℞-only
Pharmacokinetic data
Protein binding	~55%
Elimination half-life	~14 hours
Identifiers
IUPAC name N-[5-(aminosulfonyl)-3-methyl-1,3,4-thiadiazol-2(3H)-ylidene]acetamide
CAS Number	554-57-4 Y
PubChem CID	4100
IUPHAR/BPS	6828
DrugBank	DB00703 Y
ChemSpider	3958 Y
UNII	W733B0S9SD
KEGG	D00655 N
ChEMBL	ChEMBL19 N
CompTox Dashboard (EPA)	DTXSID1023281
ECHA InfoCard	100.008.243
Chemical and physical data
Formula	C5H8N4O3S2
Molar mass	236.26 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=S(=O)(C\1=N\N(C(=N/C(=O)C)/S/1)C)N
InChI InChI=1S/C5H8N4O3S2/c1-3(10)7-4-9(2)8-5(13-4)14(6,11)12/h1-2H3,(H2,6,11,12)/b7-4- Y Key:FLOSMHQXBMRNHR-DAXSKMNVSA-N Y
NY (what is this?)  (verify)

This drug has displayed teratogenic effects in rats. Compared to another drug in the same class, acetazolamide, methazolamide requires a lower dose when administered to patients.

Recently, research has also uncovered a potential new role for this drug, addressing tau toxicity, a theorized cause for diseases such as Alzheimer’s.

Further reading

• Iyer GR, Bellantone RA, Taft DR (February 1999). "In vitro characterization of the erythrocyte distribution of methazolamide: a model of erythrocyte transport and binding kinetics". Journal of Pharmacokinetics and Biopharmaceutics. 27 (1): 45–66. doi:10.1023/A:1020630712388. PMID 10533697. S2CID 24294348.
• RxList. "Neptazane". Archived from the original on August 12, 2006. Retrieved August 20, 2006.
• Shirato S, Kagaya F, Suzuki Y, Joukou S (April 1997). "Stevens-Johnson syndrome induced by methazolamide treatment". Archives of Ophthalmology. 115 (4): 550–553. doi:10.1001/archopht.1997.01100150552021. PMID 9109770.
• Skorobohach BJ, Ward DA, Hendrix DV (February 2003). "Effects of oral administration of methazolamide on intraocular pressure and aqueous humor flow rate in clinically normal dogs". American Journal of Veterinary Research. 64 (2): 183–187. doi:10.2460/ajvr.2003.64.183. PMID 12602587.