Drug reference

Hydroxyprogesterone Caproate

Progestogen · Progestational agent, Uterine relaxant

Also known as 17alpha-Hydroxyprogesterone Caproate, 17-OHPC, Progesterone Caproate

ProgestogenProgestational agent, Uterine relaxantATC G03DA03

CDSCO approvedSchedule HATC G03DA03

EXCRETION

—

not curated

INTERACTIONS

—

none in our sources

PREGNANCY

Not applicable under the current FDA labeling system. Clinically, it is used during pregnancy for the prevention of recurrent spontaneous preterm birth, where the benefit outweighs the potential risk. However, it is contraindicated for general use in pregnancy not for this specific indication.

FDA category + note

Mechanism

Hydroxyprogesterone caproate is a synthetic progestogen that works by binding to progesterone receptors, primarily in the uterus. It helps to relax uterine smooth muscle, stabilize the uterine environment, and prevent cervical shortening. In pregnant women with a history of spontaneous preterm birth, it is thought to reduce uterine contractility and inflammatory processes, thereby extending gestation.

Indications

Prevention of recurrent spontaneous preterm birth in women with a singleton pregnancy who have a history of spontaneous preterm birthRecurrent miscarriage (off-label)Dysfunctional uterine bleeding (off-label)prevention of preterm birth (in women at increased risk due to previous preterm delivery)

Dosing

Adult: For prevention of recurrent spontaneous preterm birth: 250 mg administered intramuscularly once weekly, starting from 16 to 20 weeks of gestation and continuing until 36 weeks of gestation.
Pediatric: Not indicated for pediatric use.
Renal adjustment: No specific dose adjustment is generally required for renal impairment, but caution is advised in severe cases due to potential accumulation of metabolites.
Hepatic adjustment: Contraindicated in severe hepatic impairment. Use with caution and monitor liver function in patients with moderate hepatic impairment.
Geriatric: Not indicated for geriatric use as it is used specifically in pregnant women of reproductive age.
Max dose: The maximum recommended dose for preterm birth prevention is 250 mg once weekly.

Pharmacokinetics

Onset

Not immediate for full clinical effect; peak plasma levels are reached within days of IM injection, but sustained levels are achieved over weeks.

Peak effect

Approximately 3-7 days after IM administration for a sustained effect due to the caproate ester forming a depot.

Duration

Approximately 7 days due to slow release from the IM depot.

Half-life

Approximately 16-20 days (terminal half-life after IM administration due to slow absorption).

Bioavailability

Not applicable for IM administration.

Protein binding

Approximately 90% (primarily to albumin).

Metabolism

Primarily hepatic, via cytochrome P450 (CYP) enzymes, particularly CYP3A4, to various metabolites.

Excretion

Primarily via urine and feces as metabolites.

Contraindications

Active or history of thrombophlebitis, thromboembolic disorders, or cerebral vascular disease
Known or suspected breast cancer, other hormone-sensitive cancers, or history of such conditions
Undiagnosed abnormal vaginal bleeding
Cholestatic jaundice of pregnancy or severe liver dysfunction/disease
Uncontrolled hypertension
Hypersensitivity to hydroxyprogesterone caproate or any component of the formulation

Side effects

Common

Injection site reactions (pain, swelling, itching, bruising)Nausea, diarrhea, constipationHeadache, dizzinessMild fluid retention, edemaMood changes, depressionSkin rash, pruritusElevated blood glucose levels (transient)

Serious

Thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism)
Hypersensitivity reactions, including angioedema, urticaria, anaphylaxis
Hypertension
Gestational diabetes (increased risk)
Depression (new onset or exacerbation)
Jaundice, liver dysfunction
Cervical insufficiency (can worsen in some cases)

Pregnancy & lactation

Pregnancy

Lactation

Hydroxyprogesterone caproate and its metabolites are excreted into breast milk. The effects on a breastfed infant are unknown. Use with caution; benefits of breastfeeding versus potential risks to the infant should be considered.