Therapeutic Classification

progestin Registry

Clinical reference for progestin medications. Access safety monographs, dosing adjustments, and drug-drug interactions for all registered brand names and generics in this class.

Registered Medications (progestin)

Medication	Therapeutic Class	Maternal Safety
17-Alpha Hydroxyprogesterone Caproate Intramuscular synthetic progestogen (C21 steroid) historically used for prevention of recurrent spontaneous preterm birth (sPTB) in singleton gestations with a prior sPTB. The landmark MFMU Network PREIS trial (Meis et al., NEJM 2003) demonstrated a 34% relative risk reduction in PTB <37 weeks, forming the basis of FDA accelerated approval of Makena (AMAG Pharmaceuticals) in 2011. However, the adequately powered PROLONG trial (Blackwell et al., 2019), conducted in a broader international population, failed to replicate efficacy on either primary or secondary outcomes. The 2021 EPPPIC individual patient data meta-analysis (Lancet) further confirmed no significant benefit on neonatal composite outcomes for 17-OHPC IM. Following an FDA advisory committee vote in 2019 and a formal benefit-risk reassessment, the FDA withdrew approval of Makena in April 2023 — the first withdrawal of an obstetric drug under the accelerated approval pathway. Current ACOG guidance (Practice Bulletin 234, reaffirmed 2023) and SMFM no longer recommend 17-OHPC IM as a standard strategy for sPTB prevention. Vaginal progesterone (90 mg gel or 200 mg micronized capsule) remains the preferred option for asymptomatic patients with a singleton pregnancy and sonographic short cervix (≤25 mm) at 16–24 weeks, supported by individual patient data meta-analyses (IPDMA, Romero et al., 2018).	Progestogen; synthetic C21 pregnane steroid; 17α-hydroxyprogesterone ester; progestin (IM depot formulation)	caution
DROSPIRENONE, ETHINYL ESTRADIOL AND LEVOMEFOLATE CALCIUM Inducers of CYP450 enzymes (eg carbamazepine) may decrease estrogen levels Increases risk of thromboembolic disorders and endometrial cancer.	Progestin + Estrogen	avoid
ESTRADIOL AND NORETHINDRONE ACETATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
ESTRADIOL AND PROGESTERONE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
ETHINYL ESTRADIOL; ETONOGESTREL Hepatic enzyme inducers may decrease efficacy and increase breakthrough bleeding Must be removed if a patient becomes pregnant.	Progestin	avoid
HYDROXYPROGESTERONE CAPROATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
MEDROXYPROGESTERONE ACETATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
MEGESTROL ACETATE Can increase the effects of warfarin Can cause thromboembolic phenomena and adrenal suppression.	Progestin	avoid
NORETHINDRONE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE ACETATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE ACETATE AND ETHINYL ESTRADIOL AND ETHINYL ESTRADIOL AND FERROUS FUMARATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE ACETATE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE AND ETHINYL ESTRADIOL CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE AND ETHINYL ESTRADIOL (10/11) CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE AND ETHINYL ESTRADIOL (7/14) CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORETHINDRONE AND MESTRANOL CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid
NORGESTIMATE; ETHINYL ESTRADIOL Inducers of CYP450 enzymes (eg carbamazepine) may decrease estrogen levels Increases risk of thromboembolic disorders and endometrial cancer.	Progestin + Estrogen	avoid
PROGESTERONE CYP3A4 inducers can decrease efficacy Can cause thromboembolic disorders.	Progestin	avoid

This therapeutic registry is dynamically synthesized from professional clinical sources. Listing of a medication does not imply equivalence; refer to individual monographs for head-to-head pharmacological data.