On the issue of obesity, we welcome the wise recommendation of the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) to reiterate its refusal to grant the marketing authorisation to the fixed-dose combination of topiramate and phentermine – an antiepileptic and an appetite-supressant amphetamine – after following the guidance of the recently established Pharmacovigilance Risk Assessment Committee (PRAC). (1)

A weight loss of a few kilograms achieved during therapy cannot justify exposing patients to the known adverse effects of the two drugs combined such as psychiatric disorders, cardiac arrhythmias and metabolic acidosis. (2) And yet, given the attractiveness of the anti-obesity market, submissions for marketing approval are expected for other similarly dangerous appetite-supressants, such as lorcaserine, lisdexamfetamine, liraglutide and a combination of bupropion-naltrexone. (3)

Credit is due to the European Medicines Agency (EMA), which has clearly prioritized patient safety and public health in this instance, by saying no to the hazardous phentermine-topiramate combination and issuing a diametrically-opposed recommendation to that of the US Food and Drug Administration.

But not all is quiet in the western front, with plenty of other risky medicines under review at the PRAC and CHMP, among which the respiratory stimulant almitrine, the anti-inflammatory diclofenac, the anti-emetic domperidone, the anti-anemia iron dextran, the benzodiazepine tetrazepam, not to mention the third- and fourth-generation combined oral contraceptives. (4) (5)

All eyes are on the EMA: will the precautionary principle prevail and the lessons learnt from past public health disasters be taken on board? Will the agency follow suit, stick to its guns and “first, do no harm”? (3)

> Read this response online at bmj.com

©Prescrire 26 April 2013

References:
1 - European Medicines Agency. Refusal for the marketing authorisation for Qsiva (phentermine/topiramate). Questions and Answers. 21 February 2013. Available at: http://www.ema.europa.eu/docs/en_GB/document_library/Summary_of_opinion_-_Initial_authorisation/human/002350/WC500139215.pdf

2 - Prescrire Editorial Staff “Topiramate+phentermine, an excessively dangerous appetite-supressant combination” Prescrire Int 2013; 22 (136): 61-64. > Pdf, subscribers only

3 - Prescrire’s response to the EMA Consultation on the revision of the guidelines on medicinal products used in weight control. Medicinal products used in weight control: first, do no harm! December 2012. > Free

4 - SCRIP. Fragrance or Folly: 15 drug events will resolve before April. Informa news. 22 February 2013.

5 - European Medicines Agency. PRAC: Agendas, minutes and highlights webpage. Accessed on 25 March. Available at: http://www.ema.europa.eu/ema/index.jsp?curl=pages/about_us/ document_listing/document_listing_000353.jsp&mid=WC0b01ac05805a21cf