Multiple prominent gelatinous mulberry-shaped nodules form beneath the corneal epithelium during the first decade of life in gelatinous drop-like corneal dystrophy which cause photophobia, tearing, corneal foreign body sensation and severe progressive loss of vision. Lisch epithelial corneal dystrophy is characterized by feather shaped opacities and microcysts in the corneal epithelium that are arranged in a band-shaped and sometimes whorled pattern. Painless blurred vision sometimes begins after sixty years of life.Corneal stromal dystrophies – Macular corneal dystrophy is manifested by a progressive dense cloudiness of the entire corneal stroma that usually first appears during adolescence and eventually causing severe visual impairment. In granular corneal dystrophy multiple small white discrete irregular spots that resemble bread crumbs or snowflakes become apparent beneath Bowman zone in the superficial central corneal stroma. They initially appear within the first decade of life. Visual acuity is more or less normal. Lattice dystrophy starts as fine branching linear opacities in Bowmans layer in the central area and spreads to the periphery. Recurrent corneal erosions may occur. The hallmark of Schnyder corneal dystrophy is the accumulation of crystals within the corneal stroma which cause corneal clouding typically in a ring-shaped fashion.Posterior corneal dystrophies – Fuchs corneal dystrophy presents during the fifth or sixth decade of life. The characteristic clinical findings are excrescences on a thickened Descemet membrane (cornea guttae), generalized corneal edema and decreased visual acuity. In advanced cases, abnormalities are found in all the layers of the cornea. In posterior polymorphous corneal dystrophy small vesicles appear at the level of Descemet membrane.
Two-thirds of the parent compound breaks down into the active metabolite N-desmethyl-zolmitriptan (183C91), while the remaining one-third separates into the other two inactive metabolites: zolmitriptan N-oxide and an indole acetic acid derivative. It has an elimination half-life of about three hours before it undergoes renal elimination; its clearance is greater than the glomerular filtration rate suggesting that there is some renal tubular secretion of the compound. Economics
Brand names
Zolmitriptan is marketed by AstraZeneca with the brand names Zomig, Zomigon (Argentina, Canada & Greece), AscoTop (Germany) and Zomigoro (France). Economics
In 2008, Zomig generated nearly $154 million in sales.AstraZenecas U.S. patent on Zomig tablets expired on November 14, 2012, and its pediatric exclusivity extension expired on May 14, 2013. The patent in certain European countries has already expired too, and generic drug maker Actavis released a generic version in those countries, starting in March 2012. Legal status
In Russia versions of zolmitriptan, which are not registered in the National registry of medications, may be regarded as narcotic drugs (derivatives of dimethyltriptamine). References
Further reading
MacGregor EA (1998). "Zolmitriptan clinical studies". Drugs Today. 34 (12): 1027–1033. doi:10.1358/dot.1998.34.12.487488. PMID 14743270. External links
"Zolmitriptan". Drug Information Portal. U.S. National Library of Medicine. "Zolmitriptan Nasal Spray". MedlinePlus.