Healthy Skepticism International News
3M Duromine (phentermine)
April 1998
Vol 16 Issue 3/4 3M claims Duromine (phentermine) has "Proven efficacy in general practice" and "A safety profile you have come to trust" but the evidence is thin.
3M’s high aspirations
The 3M Web site states that: “At 3M, we pride ourselves in forming innovative relationships within our organization, with suppliers and customers, between domestic and international business units—relationships that respect individual and cultural differences and result in products that make life better for all of us.”
During February and March 1998 3M has attempted to enhance its relationships with Australian doctors by offering bribes. These have included:
Post-it notes for providing 3M with marketing information.
Colourful socks featuring pictures of 3M salbutamol inhalers.
A chance to win a 3M Littman Master Cardiology Stethoscope for adding one word to a sentence to complete a promotional claim for 3M’s salbutamol inhaler.
The Chairman of the Board and Chief Executive Officer of 3M, Mr L.D. DeSimone has the following high aspirations:
“At 3M, we are committed to satisfying our customers with superior quality and value; providing investors with an attractive return through sustained, high-quality growth; respecting our social and physical environment; and being a company of which employees are proud.”
The 3M Web site also asserts that the company has an “Innovative Culture”: “Innovation is required at 3M. Thirty percent of each year’s sales must come from products less than 4 years old.”
By contrast, this month’s topic is new promotion of a very old drug: Duromine (phentermine). It appears to be a case of flogging an old horse now that it has a chance of doing well only because the leading horses (fenfluramine and dexfenfluramine) have died after a collision (with phentermine).
A slim history of anti-obesity drugs in Australia
Duromine (phentermine) is an old drug that stimulates adrenergic neurotransmitter pathways in the brain. 3M’s best evidence to support its use appears to be a 1968 trial by Munro et al1 which showed a significant difference in weight loss between the phentermine and placebo groups at 36 weeks. However, there was no follow up after treatment ceased. A review of anti-obesity drugs published in the April 1998 Medical Journal of Australia concludes that “no studies have examined long term use of these agents [adrenergic agonists] and, as there is evidence that patients regain weight when they stop taking these drugs, their usefulness is limited.”.2
Many years ago, phentermine was overtaken in the Australian market place by dexfenfluramine (Servier’s Adifax). The latter gained endorsement from a number of influential “experts” in Australia. This was despite the fact that there was no evidence of long term benefit from dexfenfluramine and despite the drug’s association with pulmonary hypertension. The success of Adifax appears entirely due to misleading promotion. Roughead’s audio-tapes of sales “reps” presentations in 1994 includes one about Adifax that includes many contradictions of the Approved Product Information including: “it’s quite safe to use long term.“3
In August 1996 we referred our concerns about the promotion of dexphenfluramine to the Therapeutic Goods Administration (TGA, the Australian FDA). In September 1996 the TGA promised to “initiate a regulatory process” and to advise us “of the outcome in due course”. As of 31 April 1998 an “outcome” has not yet been reached! In December 1997 we referred these issues to the Australian Competition and Consumer Commission (ACCC) which is supposed to be responsible for enforcing the Trade Practices Act and for supervising voluntary regulation systems. To our surprise the ACCC have refused to regulate prescription drug promotion even when all the other systems have failed.
Meanwhile our concerns about the poor quality of the evidence used by Servier to promote dexphenfluramine have been more than vindicated. A rash of prescribing of the very similar drug fenfluramine in combination with phentermine in the USA led to the detection of an association with heart valve damage. In a misleading letter to Australian doctors in September 1997 Servier claimed that “the valvulopathies described in the US have not been reported where these products have been used alone”. The truth is that the US FDA reported 9 cases of valve damage in patients treated with dexphenfluramine alone.
Dexphenfluramine and fenfluramine were withdrawn worldwide in September 1997. Phentermine was not withdrawn.
The Australian Adverse Drug Reaction Advisory Committee (ADRAC) did not receive any reports of heart valve damage associated with these drugs until after the withdrawals. However, ADRAC received 3 such reports within a few months once Australian doctors became aware that such an association was possible.4 This illustrates the fact that serious adverse effects of drugs may remain undetected for very many years if the link between the drug and the adverse effect is not obvious.
An opportunity for better care or bigger profits?
What happens to prescribing when health authorities stop paying for drugs or when useless and/or dangerous products are withdrawn from the market? Unfortunately, prescribing does not always improve. For example, in the 1980s, the American State of New Jersey removed a large number of ineffective medications from its Medicaid formulary. Reductions in the use of the withdrawn drugs were offset by increases in a variety of substitute drugs that varied substantially in cost and efficacy.
Some switches were improvements. Patients who had been receiving irrational fixed-ratio combinations of theophylline and barbiturates tended to get bronchodilators without sedatives, a therapeutically more rational choice.
Sadly, many replacement drugs were not improvements. For example, recipients of “cerebral vasodilators” were often switched to papaverine or ergoloid mesylates. Both of the “new” drugs are costly and lack good evidence of efficacy.5
Now that fenfluramine and dexfenfluramine are gone, it appears that 3M Pharmaceuticals is hoping that the latter scenario will prevail. Taking advantage of the new gap in the market 3M has mailed a brochure to Australian doctors featuring slogans like “proven efficacy in general practice” and “a safety profile you’ve come to trust”. MaLAM has a number of serious concerns about these advertisements:
They explicitly state that the product is safe;
There is selective quotation from a study on obese diabetics;
They imply that Duromine has long-term effectiveness;
They do not reflect current medical thinking about the treatment of obesity.
The MaLAM letter to 3M re Duromine
1. Munro JF, MacCuish AC, Wilson EM, Duncan LJP. Comparison of continuous and intermittent anorectic therapy in obesity. BMJ 1968; 1: 352-354.
2. Proietto J. Anti-obesity drugs. .Med J Aust 1998; 168: 8: 409-412
3. Roughead EE. The Pharmaceutical Representative and Medical Practitioner Encounter: Implications for Quality Use of Medicines. Masters Thesis, La Trobe University, Melbourne, August 1995 http://web.archive.org/web/20041209055211/http://www.healthyskepticism.org/reps/tindex.htm
4. Withdrawal of fenfluramine and dexfenfluramine. ADRAC Bulletin 1998; 17: 1: 3
5. Soumerai SB, Ross-Degnan D, Gortmaker S, and Avorn J. Withdrawing payment for nonscientific drug therapy: intended and unexpected effects of a large-scale natural experiment. JAMA 1990; 263: 831-839.
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