Hydroxyprogesterone Caproate

What About Compounded Hydroxyprogesterone?

Hydroxyprogesterone injections have been available through compounding pharmacies for quite some time, long before hydroxyprogesterone caproate was approved. These compounded injections cost much less than hydroxyprogesterone caproate and have long been used to prevent preterm birth.
Usually, once a manufacturer performs all the necessary studies and receives FDA approval, compounding pharmacies are no longer allowed to make such products. However, the FDA recognizes that this is a unique situation and has stated that it will allow compounding pharmacies to continue to make hydroxyprogesterone injections, at least for the time being.

How Does Hydroxyprogesterone Caproate Work?

Hydroxyprogesterone caproate is a synthetic (manufactured), long-acting version of progesterone, a hormone that is very important to maintaining a pregnancy. It is not yet known for certain how exactly the drug works to prevent preterm labor.

Clinical Effects

In studies, hydroxyprogesterone caproate was shown to reduce the risk of preterm birth in women with a history of it. Specifically, 37.1 percent of women receiving hydroxyprogesterone caproate injections delivered before 37 weeks, compared to 54.9 percent of women receiving placebo injections, which are injections that contain no active ingredients.

When and How to Use It

Some general considerations to keep in mind with hydroxyprogesterone caproate include the following:
  • This medication comes as an injection. It is injected by a healthcare provider once a week (once every seven days). It is started sometime between 16 and 21 weeks of pregnancy and continued until 37 weeks of pregnancy.
  • The injections are given in the upper-outer area of the buttocks, near the hip.
  • For hydroxyprogesterone caproate to work properly, it must be given as prescribed.
Last reviewed by: Kristi Monson, PharmD
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