Editorials

# Direct to consumer advertising of prescription drugs

BMJ 2008; 337 (Published 02 September 2008) Cite this as: BMJ 2008;337:a985
1. Barbara Mintzes, assistant professor, therapeutics initiative
1. 1Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada V6T 1Z3
1. bmintzes{at}chspr.ubc.ca

Even attenuated forms such as cross border advertising can lead to unnecessary harm

Are there public health consequences when regulators turn a blind eye to cross border advertising that contravenes national laws? Although Canada prohibits direct to consumer advertising of prescription drugs, no steps are taken to prevent US advertising from reaching the Canadian public. The linked study by Law and colleagues (doi: 10.1136/bmj.a1055), provides compelling evidence that this does have consequences for public health and of the need for better regulatory oversight.1

Direct to consumer advertising from the United States reaches Canadians via cable television and US magazines sold in Canada. Law and colleagues found that cross border advertising increased prescribing of a minimally effective drug with a poor safety profile,2 which subsequently led to its withdrawal.3

French speaking Canadians, who mainly live in Quebec, watch less US television than their English speaking compatriots and are less exposed to US direct to consumer advertising. Law and colleagues used this difference to examine the effects of US advertising campaigns on prescribing rates. Three drugs met the inclusion criteria of the study on the basis of timing of approval and advertising—tegaserod, etanercept, and mometasone. A clear effect was found for one, tegaserod, a drug for irritable bowel syndrome in women and for chronic constipation.

Direct to consumer advertising had no significant effect on the prescription of etanercept, a biological agent given by infusion to treat rheumatoid arthritis. Etanercept is generally used after failure of initial treatment, and special authorisation is needed for public reimbursement. With a restricted patient population and limited use, the influence of advertising is expected to be attenuated.

Similarly, the lack of observed difference in prescribing of mometasone, a nasal steroid prescribed for allergy in primary care, is not surprising. This drug is fully subsidised in Quebec, not funded at all in Ontario, and is given only to children under 12 in British Columbia and Alberta. Alternatives such as beclometasone are fully subsidised.

Just 40% of the costs of drugs are paid for publicly in Canada.4 However, reimbursement policies can have profound effects on prescribing. British Columbia’s restrictive funding of cyclo-oxygenase-2 inhibitors resulted in less than half the prescribing rate seen elsewhere in Canada, with lower rates extending to those without public coverage.5 British Columbians were exposed to more US advertising, but Quebec, with unrestricted funding, had higher rates of use. In the current study, inhaled mometasone was prescribed more often in Quebec throughout the observational period.

Law and colleagues found a 42% increase in prescribing of tegaserod after intensive US advertising campaigns, or an estimated 29 574 extra prescriptions over a two year period (personal communication, 2008). Tegaserod was not covered by public drug plans, but at average costs to large private insurers of $169.44 (£85; €108) for each prescription (B Martinez, personal communication, 2008), this translates to more than$C5m (£2.5m).

In a pooled analysis of 29 clinical trials, 13 of 11 614 patients treated with tegaserod had heart attacks, strokes, or serious angina compared with one of 7031 patients on placebo.3 Among the extra prescriptions in Canada as a result of direct to consumer advertising, around 29 people, or one in 1023 patients treated, would have experienced serious cardiovascular events over the two years.

Women experienced 88% of the cardiovascular events leading to the withdrawal of tegaserod.3 In the only analysis of drug safety withdrawals disaggregated by sex, eight of 10 US withdrawals from 1997 to 2001 led to greater harm to women. In four cases this was because of more frequent use by women and in four because of higher risks of cardiac arrhythmias and dose related effects.6

Whether direct to consumer advertising leads to disproportionate harm to women is currently under debate in a Canadian court case, in which a media company, Canwest Media, is challenging the ban on direct to consumer advertising as an infringement of its freedom of expression. Health Canada is defending the law on public health grounds. A coalition of unions and non-profit making organisations has obtained standing in court on the government side to introduce two additional concerns—harm to women and effects on employee health benefits.

Central to these concerns is advertising’s ability to “expand the boundaries of treatable illness,” 7 shifting the balance of potential benefit to harm as drugs are used for milder problems. Tegaserod is used to treat irritable bowel syndrome, a condition Moynihan and colleagues highlighted as a case study in disease mongering, “What for many people is a mild functional disorder—requiring little more than reassurance about its benign natural course—is currently being reframed as a serious disease attracting a label and a drug.”7 The 2003 television campaign mentioned by Law and colleagues, which won an advertising award, suggests widespread use, with its panned images of women of many ages and ethnic backgrounds. A comparison with laxatives implies use for mild everyday problems.8

Law and colleagues found a larger increase in prescribing to Medicaid patients in the US than in Canada. This probably reflects both the higher exposure to advertising and majority female population. Tegaserod’s intense advertising continued after the withdrawal of rofecoxib, despite safety advisories,9 10 and despite concerns raised about the role of advertising in fuelling the use of rofecoxib.11

This study adds a note of caution to existing evidence on the effects of direct to consumer advertising. The lesson for Europe, which is considering the introduction of such advertising, and for Canada, which has inadequate enforcement, is that even attenuated forms such as cross border advertising drift can cause unnecessary harm.

## Footnotes

• Research, doi: 10.1136/bmj.a1055
• Competing interests: BM has helped the Canadian Department of Justice with expert testimony in defence of Canada’s prohibition of direct to consumer advertising of prescription drugs, in a legal challenge by Canwest Media in the Ontario Superior Court. She is also on the steering committee of Women and Health Protection, part of the coalition with intervener status in the case.

• Provenance and peer review: Commissioned; not externally peer reviewed.

## References

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