According to a review Procter & Gamble's Intrinsa testosterone patches designed to boost post-menopausal women's flagging sex drive may not actually work. The Drug and Therapeutics Bulletin (DTB), a top medical journal has also raised doubts on the long term safety of Intrinsa and criticised trials of the treatment as flawed and inconclusive. Intrinsa is licensed for use in Europe but not in the United States as regulators citing lack of evidence for the long-term safety of the patch voted against its approval. Procter & Gamble Pharmaceuticals said the Intrinsa patch had been thoroughly tested, and had been shown to be effective.
Women who undergo menopause can experience a reduction of sexual desire which is known as hypoactive sexual desire disorder (HSDD) and is believed to be linked to low levels of the sex hormone testosterone. The Intrinsa patch by releasing a daily dose of the hormone into the blood stream from a patch worn on the lower abdomen is said to correct the problem and is prescribed for women with HSDD who are also receiving therapy to top up levels of another sex hormone, oestrogen.
Ike Iheanacho, editor of the Drug and Therapeutics Bulletin, which published the review of published studies said, "The published evidence so far is based on highly selected women and only shows small improvements in sexual parameters and large placebo responses. Also the long term safety of the treatment is unknown. Unwanted side effects are common and not always reversible. For all these reasons, we cannot recommend Intrinsa for use in women with sexual dysfunction."
Iheanacho and colleagues reviewed studies of Intrinsa that included nearly 4,000 women. The researchers said as most of the trials lasted less than six months it was difficult to determine long-term safety.
The researchers said that a despite being given a placebo a significant number of women reported an improvement in their sex life which indicated that low levels of testosterone might not have been the problem in the first place. In other instances the researchers said the women reported having sex up to three times a month before the trials - raising questions over whether they had a poor sex drive at all from the outset.
They also highlighted the side effects of the patch such as acne, hair loss, skin reactions, weight gain, migraine and insomnia. The journal said question marks remained about both the effectiveness and safety of Intrinsa. "For all these reasons, we cannot recommend Intrinsa for use in women with sexual dysfunction."
In a statement Procter & Gamble Pharmaceuticals said, "This testosterone patch has been studied in clinical trials involving over 1,000 surgically menopausal women with low sexual desire causing distress, treated for up to six months and was shown to be well tolerated.
"The company has also put in place an independent safety advisory board and a robust risk management plan which is shared on a regular basis with the European Regulatory Authorities.
"In these clinical studies, the testosterone patch was shown to significantly increase satisfying sexual activity, increase sexual desire and reduce the related distress. These results were statistically significant versus women treated with placebo." (Harkiran has contributed to this story)