This colour advertisement shows an attractive, well-groomed woman, laughing as she leans back in the arms of a man with a tiger's head. The tiger is winking. He is visibly wearing a wedding ring, as do men in many Viagra ads. The setting appears to be the couple's living-room.

The telegraphic phrase 'Welcome back Tiger' suggests that the couple previously had an exciting sexual relationship that became unsatisfactory at some point. Now the excitement has been restored. There is a pun in the phrase 'Performance you can trust' at the bottom of the photograph.

Also at the bottom of the photograph, the advertisement asks, 'Why do patients keep coming back for Viagra?'. No evidence is given that patients do keep coming back for Viagra; this is presented as fact without substantiation. The one-word answer, 'Confidence', implies that patients keep coming back for Viagra because it gives them confidence or because they are confident about the benefits of taking Viagra. The reference to a journal article[1] implies that there is research evidence to substantiate such assertions. However, the article provides no such evidence. Instead, it is a validation study focusing on the treatment responsiveness of the Self-Esteem And Relationship (SEAR) questionnaire in erectile dysfunction (ED).

The study was funded by Pfizer. The lead author was a paid consultant to Pfizer, and the other six authors were Pfizer employees. It is not unusual for pharmaceutical companies to fund the development of questionnaires that can be used in clinical trials of their products. For example, Eli Lilly, dissatisfied with the 'gold standard' Hamilton Depression Rating Scale, has attempted to validate alternative scales to assess antidepressant efficacy[2]. Pharmaceutical companies also fund guidelines that may be biased in their favour.[3] [4] There is substantial evidence that findings of studies funded by pharmaceutical companies are more likely to favour industry than those funded from other sources.[5] [6] Not surprisingly, pharmaceutical advertisements often cite studies funded by the companies that produce the drugs.

However, the study cited in this advertisement is not relevant to the likely interpretation of the question 'Why do patients keep coming back for Viagra?'. The reported confidence of the participants did increase relative to baseline over the ten-week, open-label, flexible-dose trial. However, there was no placebo or other drug comparator. The increase in confidence could have been due to many factors other than Viagra, including: placebo response; regression to the mean; relief at being offered assessment and treatment, information, reassurance, and hope; and improved communication with their partners. Furthermore, participants were Viagra-naïve at the start of the trial, and needed to have taken only one dose to be included in the analysis. It was not reported how many doses they actually took. Men who have only ever had one dose (or a few doses) can hardly be said to 'keep coming back'.

So do men keep coming back for Viagra? Reported discontinuation rates for Viagra vary. Analysis of data from Pfizer clinical trials of at least four weeks' duration revealed a 10% discontinuation rate for Viagra (20% for placebo).[7] However, another study found a 34.6% discontinuation rate within six months among successfully treated men[8] (success was defined on the basis of International Index of Erectile Function scores[9]). The discontinuation rate among all treated men was not reported, but it is likely to have been substantially higher among men for whom Viagra was less effective. Among men for whom it was not effective, the discontinuation rate is likely to have been at or near 100%.

Discontinuation rates increase with length of follow-up. A US study found that 97 of 197 men (49%) were still using Viagra after two and a half years.[10] A Taipei study found a discontinuation rate of 80.2% among 1074 men followed up for one to three years after being prescribed Viagra.[11]

Discontinuation rates are sometimes reported as refill rates. A US study found that 62% of men renewed their prescriptions at their first follow-up appointment three to four months after commencing treatment; by the second follow-up appointment at six to twelve months, only 40.5% of the original series of men did so.[12] The overall refill rate is 50% or less.[13] So many men do keep coming back for Viagra, but many do not.

Many men find that Viagra does not work for them, or does not work as well as they expect it to, often on the basis of media hype. This can severely worsen their distress about ED.[14]

The timing of this advertisement is significant. Viagra has two significant new competitors, Cialis (tadalafil/Lilly) and Levitra (vardenafil/GlaxoSmithKline/Bayer), both available in Australia. All three drugs are similarly priced at approximately $70.00 for four full-strength tablets. None is available on the Pharmaceutical Benefits Scheme, but Viagra and Cialis are available on the Repatriation Pharmaceutical Benefits Scheme at a cost of $3.80 to the patient.[15]

Cialis has a longer half-life and is not clinically influenced by food or alcohol.[16] Levitra acts faster and is promoted as a more specific inhibitor of the PDE5 enzyme.[17]

There has been extensive media coverage for Cialis and Levitra, including statements like these:

Stiff opposition for Viagra[18]

Eli Lilly launches '48-hour' Viagra rival[19]

Men suffering erectile dysfunction could soon have access to a new, beefed-up "party pill" - one that lasts up to nine times as long as Viagra[20]

Impotence drugs duke it out: Study: Levitra preferred for erectile dysfunction, but Viagra and Cialis also have fans[21]

Viagra and both newer drugs have had substantial direct-to-consumer advertising (DTCA) in the United States[22] and New Zealand, the only two OECD countries that allow DTCA. In 1999, a Viagra advertisement in the New Zealand newspaper The Dominion displayed a photo of a middle-aged couple cuddling in bed, under the caption 'Bring back the spark that made you both so happy'. The advertisement was clearly suggesting that the couple had just had successful coitus. It was criticised for overstating the magnitude of the problem of erectile dysfunction, overstating the efficacy of Viagra, and understating its risks.[23]

Also in NZ, Eli Lilly used its secondary sponsorship of Team New Zealand's recent ill-fated defence of the America's Cup to promote Cialis.[24] In the US in 2003, Pfizer spent $111.6 million promoting Viagra via print, TV, radio and the Internet. The same year, GSK/Bayer spent $47 million in about four months advertising Levitra.[25]

There has been considerable de facto DTCA of Viagra in Australia. One two-page magazine advertisement in the Qantas magazine in November 2001 showed a couple closing their hotel room door (his wedding ring visible), with the text: 'Your doctor can treat your erection problems. The rest is up to you'. Pfizer have also used celebrity endorsement in newspaper advertisements featuring the legendary soccer player Pelé advocating consulting a doctor about erection problems.[26] A variant of the 'Welcome back Tiger' advertisement in the Medical Observer is now being used in newspaper advertisements.[27] The photograph is the same, the text somewhat different:

Welcome back Tiger.

Get your sex life back on track.

Ask your doctor today, which treatment options may offer you the best quality erection.

For further information online, visit www.welcomebacktiger.com.au

Pfizer Australia Pty Limited….

There has also been DTCA for Levitra in Australia. A recent Media Watch program[28] exposed how Bayer and GSK and Impotence Australia used actor Gary Sweet and the rollinthehay website (www.rollinthehay.com.au) in the Performance Pack initiative,[29] a Levitra advertising campaign thinly disguised as a men's health campaign. Although Sweet was not allowed to mention Levitra by name, he did so at least once on a radio program.[30]

In 2003, Eli Lilly was found to have violated the Medicines Australia Code of Conduct[31] by having misleading information on its Cialis website. The complaint was made by GlaxoSmithKline and Bayer, the manufacturers of Levitra. In 2004, Lilly was again found to have violated the Code (sections 3.9.1 and 9.4) by specifically promoting Cialis by name on its www.erectionproblems.com.au website.[32]

The ED drug market is worth billions of dollars annually. The US market alone is approximately $2 billion a year.[33] It is estimated that only about 10% of men with ED seek treatment, so there is a lot of potential profit at stake.[34] The battle is largely being fought via advertisements and media stunts. There have been relatively few head-to-head trials to date, and in April this year it was reported that no peer-reviewed non-pharmaceutical company sponsored trials had been published.[35] Company-funded trials have found strong preferences for Cialis and/or Levitra.[36] [37] [38] [39] However, according to the UK Drug and Therapeutics Bulletin, there is no evidence that the newer drugs are better, and published evidence suggesting that Cialis is preferred over Viagra is weak.[40] Nevertheless Pfizer has reason to be concerned, and is fighting back in its advertisements.

It is likely that many men who have previously tried Viagra will try Cialis and/or Levitra. The 'Welcome back tiger' advertisement has echoes of the 'I came back to Brylcreem' television advertisement several decades ago, with its message of returning to old faithful after being lured away by competitors.

The advertisement makes no mention of common risk factors for ED. These include age, lack of exercise, obesity, diabetes, hypertension, tobacco smoking, excessive alcohol consumption, prescribed drugs[41] (including antidepressants and anti-hypertensives), and low socioeconomic status.[42] [43][44] [45] [46] [47] [48] [49] [50] There is no mention of non-pharmacological approaches that directly address relevant risk factors, particularly exercise[51] and weight loss.[52] Nor is there any mention of psychological causes of ED[53] [54] [55] [56] or psychotherapeutic interventions.[57] [58]

The tiger's wink is directed at the reader, not at his wife. How should we interpret this?: does she know that he is using Viagra, or is it a sly secret between the tiger and his doctor? There is further ambiguity in the use of the term 'patients', rather than 'men'. Together with the implicit female voice in 'Welcome back Tiger', and the woman's gaze at the reader, this suggests that doctors might be consulted by women about their partners' sexual performance. It reinforces the idea that Viagra benefits women as well as men, by improving their partners' sexual performance. However, many female partners are not enthusiastic about resuming sex or having it more often.[59] A follow-up study of men who discontinued Viagra despite successful treatment with Viagra found that the majority reported having no opportunity or desire for sexual intercourse or lack of interest from their partners.[60] Furthermore, many female partners report being unhappy about the effects of Viagra on their relationships.[61] A key issue is the reinforcement of the idea that real sex is penetrative sex.[62]

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