Pfizer has launched its contraceptive injection Sayana Press (medroxyprogesterone acetate) in the UK, hoping the convenience of a long-acting jab will overcome any temporary discomfort.
The subcutaneous injection, the first of its kind, has to be administered into the thigh or abdomen by a doctor or nurse every 13 weeks via the company’s prefilled Uniject injection.
Dr Sharon Cameron, a consultant gynaecologist and part-time senior lecturer at the University of Edinburgh, said: “Women forgetting to take their pill every day is one of the most common causes of unplanned pregnancy. Sayana Press provides an attractive and effective option for women with busy lifestyles looking for the convenience of a long-acting contraceptive.”
Sayana Press could benefit from the growing popularity of long-acting reversible contraceptives, the use of which has doubled over the last 10 years, but its licence includes a number of warnings.
Pfizer says that healthcare professionals whose patients wish to use it for more than two years “may wish to re-evaluate the risks and benefits” of using the treatment.
Sayana Press, which has been approved since 2004 in the US where it is marketed as Depo-SubQ Provera, works by lowering levels of oestrogen and other hormones.
But low oestrogen levels can cause bones to become thinner by reducing bone mineral density and women who use the product tend to have lower bone mineral density than women of the same age who have never used it.
There is also a warning that teenagers, whose bones are still growing rapidly, should only use Sayana Press if discussions with their healthcare professional conclude that other forms of contraception are unsuitable or unacceptable.
However, when licensing the drug in 2011, the UK’s MHRA said it had no clinically significant safety concerns with Sayana Press, concluding that its benefits outweighed its risks.
The active ingredient, medroxyprogesterone acetate (MPA), is similar to the natural hormone progesterone produced in the ovaries.
In two phase III clinical studies of 1,787 women, there were no pregnancies observed with Sayana Press and over half of women did not report any significant weight changes while taking it.