Nevertheless, theoretically, patients previously dependent upon the inotropic effects of digoxin could develop heart failure and hypokalaemia could result within 1–5 hours, owing to intracellular shifts of potassium, as the effects of digoxin are reversed. Patients who require redigitalization must wait for the complexes to be eliminated from the body by the kidneys, this taking 2–3 days with normal renal function. Unfortunately, fab fragments interfere with both fluorescence excitation transfer immunoassays and radioimmunoassays for digoxin. This means that serum drug levels cannot be monitored until the drug-antibody complexes are cleared from the circulation. Intellectual property
DigiFab is used as an antidote to treat a life-threatening overdose of digoxin or digitoxin. DigiFab is manufactured and distributed by BTG international Inc. under U.S. License No. 186. DigiFab is a sterile, lyophilized preparation of digoxin-immune ovine Fab (monovalent) immunoglobulin fragments. It is prepared by isolating the immunoglobulin fraction of the ovine serum, digesting it with papain and isolating the digoxin-specific Fab fragments by affinity chromatography. These antibody fragments have a molecular weight of approximately 46,000 Da. Each vial of DigiFab, which will bind approximately 0.5 mg digoxin, contains 40 mg of digoxin immune Fab, 75 mg (approx) of mannitol USP, and 2 mg (approx) sodium acetate USP as a buffering agent. The product contains no preservatives and is intended for intravenous administration. Digibind is manufactured by GlaxoSmithkline, SpA, Parma Italy under US License No. 129. It’s distributed by GSK, Research Triangle park, NC 27709.
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.