Abstract

BMJ 2011;343:d4428 doi: 10.1136/bmj.d4428 Page 1 of 1 News NEWS Varenicline raises risk of heart problems, analysis indicates Nigel Hawkes London Smokers who use the smoking cessation drug varenicline heavysmokers arealready susceptibletocardiovascular (marketedintheUnitedKingdomasChampix)areatincreased disease,” hesaid. riskof heart problems, anew meta-analysis has concluded. In arapid response postedtoCMAJ twodoctorsfromthe Best AteamledbySonalSinghofJohnsHopkinsUniversitySchool PracticeAdvocacyCentre inNewZealand,DavidWoods and of MedicineinBaltimoreandYoon Loke of the University of MarkCaswell,putadifferentspinontheresults.Theysaythat East Anglia combinedresultsfrom14trialstoreach its inabsolute terms the increase inriskisonly0.24%, which conclusion, published inthe journal of the CanadianMedical equates toanumber needed toharm of about 400. “This isa Association, CMAJ(doi:10.1503/cmaj.110218). Pfizer,which verysmallincreaseinriskcomparedtothebenefitsofquitting manufacturesvarenicline, questioned the conclusion, whichit smoking,” they say. saidwas basedonaverysmallnumber of events. Launchedin2006,vareniclinehasprovedmoderatelysuccessful A single trial(Circulation 2010;121:221-9, doi:10.1161/ for Pfizer,giving it annual salesof around$800m(£500m; CIRCULATIONAHA.109.869008) accountedfor more than €570m).Butreportsofsuicidalthoughtsamongusersprompted half the totalnumber of events; andinrapid responsestothe the USFood andDrug Administration toorderawarningon CMAJtwo correspondentsquestioned the quoted odds ratio. the labelin2009. Last month the FDAissued asafety Themeta-analysisreports52cardiovascularevents(ischaemia, announcement about the cardiovascularsafetyof the drug arrhythmia,congestiveheart failure, sudden death, or (marketedas Chantixinthe United States) on the basisof the cardiovascularrelateddeath) in4908users of varenicline and studyinCirculation.Thisurgeddoctorstoweigh“the known 27in3308 people inthe placebogroup. Thesefiguresgive an benefitsofChantix”againstthepotentialrisksinsmokerswith odds ratio of 1.3. But the authorsused the Petomethodfor cardiovasculardisease. calculatingtheoddsratio,whichisappropriatewhentheeffect sizeissmall,theauthorssay,andthetrialshaveroughlyequal bmj.com Research: Stopping smokeless tobacco with varenicline: numbersof participants