Interactions
OHPC is not likely to affect most cytochrome P450 enzymes at therapeutic concentrations. Drug interaction studies have not been performed with OHPC. Pharmacology
Pharmacodynamics
OHPC has progestogenic activity, some antimineralocorticoid activity, and no other important hormonal activity. Progestogenic activity
OHPC, also known as 17α-hydroxyprogesterone caproate, is closer to progesterone in terms of structure and pharmacology than most other progestins, and is essentially a pure progestogen – that is, a selective agonist of the progesterone receptor (PR) with minimal or no other hormonal activity. However, OHPC has improved pharmacokinetics compared to progesterone, namely a much longer duration with intramuscular injection in oil solution.Administered by intramuscular injection, the endometrial transformation dosage of OHPC per cycle is 250 to 500 mg, and the weekly substitution dosage of OHPC is 250 mg, while the effective dosage of OHPC in the menstrual delay test (Greenblatt) is 25 mg per week. An effective ovulation-inhibiting dosage of OHPC is 500 mg once per month by intramuscular injection. However, the dose of OHPC used in once-a-month combined injectable contraceptives is 250 mg, and this combination is effective for inhibition of ovulation similarly. For comparison, the dose of medroxyprogesterone acetate (MPA; 6α-methyl-17α-hydroxyprogesterone acetate), a close analogue of OHPC, used by intramuscular injection in microcrystalline aqueous suspension in once-a-month combined injectable contraceptives, is 25 mg. It has also been said that given by intramuscular injection, 250 mg OHPC in oil solution is equivalent in progestogenic potency to 50 mg medroxyprogesterone acetate in microcrystalline aqueous suspension.
After decades of use, Squibb, the manufacturer, voluntarily withdrew the Delalutin product in the United States in 1999. Renewed interest in OHPC in the United States was sparked with a large NIH-sponsored study in 2003 that found that OHPC reduced the risk of premature birth in selected at-risk pregnant women. With follow-up data showing no evidence of harmful effects on the offspring, the FDA approved the medication, as sponsored by KV Pharmaceutical as Makena, as an orphan drug in February 2011 to reduce the risk of premature birth in women prior to 37 weeks gestation with a single fetus who had at least one previous premature birth. Society and culture
Generic names
Hydroxyprogesterone caproate is the generic name of OHPC and its INN, USAN, BANM, and JAN, while hydroxyprogesterone hexanoate was its former BANM.OHPC is often mislabeled as and confused with progesterone and 17α-hydroxyprogesterone. It should also not be confused with hydroxyprogesterone acetate, hydroxyprogesterone heptanoate, or medroxyprogesterone acetate. Brand names
OHPC is marketed throughout the world under a variety of brand names including Proluton, Proluton Depot, and Makena (US), among many others. It was also formerly marketed under brand names including Delalutin, Prodrox, and Hylutin among others, but these formulations have since been discontinued. It has been marketed under the brand names Gravibinon and Injectable No. 1 (or Chinese Injectable No. 1) in combination with estradiol valerate and under the brand name Primosiston in combination with estradiol benzoate. Availability
OHPC is marketed in the United States and throughout Europe, Asia, and Central and South America.