Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2014 Publisher: EXELGYN, 216, Boulevard Saint-Germain, 75007 Paris, France
Pharmacotherapeutic class: Other gynaecological drugs, oxytocics – prostaglandins
ATC code: G02AD06
Misoprostol (a synthetic analogue of prostaglandin E1) is used in combination with mifepristone for the termination of pregnancies of ≤ 49 days of amenorrhea.
In the event of an early termination of pregnancy, the combination of mifepristone-misoprostol leads to an increase in the success rate to about 95% of the cases and accelerates the expulsion of the conceptus. The success rate is around 95 % when 600 mg mifepristone is combined with misoprostol 400 microgram orally up to 49 days of amenorrhea.
At the recommended dosage, misoprostol induces contractions of smooth muscle fibres of the myometrium and a relaxation of the cervix uteri. The uterotonic properties of misoprostol should facilitate the opening of the cervix uteri and the expulsion of intra-uterine remains.
At the recommended dosage, misoprostol should not involve cardiac, hepatic or renal undesirable effects.
Misoprostol is rapidly absorbed following oral administration, with peak plasma levels of the active metabolite (misoprostol acid) occurring after about 30 minutes. The plasma elimination half-life of misoprostol acid is 20-40 minutes.
The free acid of misoprostol is less than 90 % bound to plasma proteins. Misoprostol is metabolised by fatty acids-oxidising systems, present in several organs of the human body.
After oral administration of 3H-misoprostol approximately 73 % of the radioactivity is excreted in urine and approximately 15 % in the faeces. Approximately 56 % of total radioactivity is eliminated within 8 hours via urine.
Administration of misoprostol with food does not change the bioavailability of misoprostol acid, but reduces the maximum plasma concentration due to a slower absorption rate.
Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, and carcinogenic potential.
At high repeated doses in rats and rabbits, misoprostol was foeto- and embryotoxic. No teratogenic potential was observed.
In single- and repeat-dose studies in dogs, rats and mice at multiples of the human dose, toxicological findings were consistent with the known pharmacological effects of the E-type prostaglandins, the main symptoms being diarrhoea, vomiting, mydriasis, tremors and hyperpyrexia.
Intra-uterine but not the intragastric delivery of misoprostol to rats significantly worsened mortality from Clostridium sordellii uterine infection, and impaired bacterial clearance in vivo.
Misoprostol has been shown to alter calcium homeostasis in neuro-2a cells and contribute to abnormal cell function in vitro. Imbalances in calcium homeostasis can potentially affect early neuronal development.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
