Hydroxyprogesterone Caproate: veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Progesyn, Proluton Depot

Species with doses

Cattle, Horses and Goats

Routes

IM

Last reviewed

1 October 2026

Indications

• Habitual abortion
• Threatened abortion
• Uterine prolapse — follow-up

Hydroxyprogesterone Caproate dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Cattle

• Habitual / threatened abortion: 500–1000 mg IM per cow weekly through critical gestation window. Dose per Indian product literature (Progesyn); hydroxyprogesterone caproate has no monograph in Papich 5e or Plumb’s.

Horses

• Threatened abortion (mare): 500–1500 mg IM weekly under veterinary supervision.

Goats

• Threatened abortion (doe): 100–250 mg IM weekly.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Habitual / threatened abortion: 500–1000 mg IM per cow weekly through critical gestation window. Dose per Indian product literature (Progesyn); hydroxyprogesterone caproate has no monograph in Papich 5e or Plumb’s.

Contraindications

Hepatic disease. Pregnancy where progestin support is not indicated. Hypersensitivity.

Species-specific warnings

Cattle: Standard for habitual / threatened abortion at 500–1000 mg IM weekly. Confirm pregnancy + rule out infectious causes first.

Horses: Mare threatened abortion: 500–1500 mg IM weekly under specialist supervision. Document luteal insufficiency before therapy.

Goats: 100–250 mg IM weekly. Doe threatened abortion.

Dogs: NOT commonly used in dogs — alternative progestins (medroxyprogesterone, altrenogest) are preferred.

Cats: NOT commonly used in cats. Anti-fertility effect when used outside pregnancy.

Adverse effects

• Local injection-site reaction
• Mammary stimulation
• Rare hepatic enzyme elevation on chronic use

Drug interactions

• PGF2α (cloprostenol, dinoprost): ANTAGONISES progestin effect (causes luteolysis) — never co-administer in pregnancy maintenance
• Estrogens: opposing endocrine effects — clinically irrelevant in standard protocols
• Corticosteroids: theoretical antagonism — limited clinical impact
• CYP3A4 inhibitors (ketoconazole, erythromycin): may increase progestin levels
• CYP3A4 inducers (phenobarbital, rifampicin): may decrease levels

Pregnancy and lactation

INTENDED for pregnancy maintenance — primary indication. Crosses placenta; high doses may masculinise female fetuses (rare at therapeutic IM doses). Excreted in milk in low amounts. Use only when clear indication (history of habitual abortion, documented luteal insufficiency). Avoid in non-pregnant females if pregnancy not desired (anti-fertility effect).

Monitoring

• Pregnancy diagnosis by ultrasound / palpation BEFORE each weekly dose
• Injection site for sterile abscess / oily granuloma — rotate sites
• Serum progesterone (if available) as treatment endpoint
• Withdrawal periods (cattle): variable per jurisdiction; verify before slaughter / dairy use
• Discontinue at expected parturition (e.g. cattle ~270 d, mare ~330 d) — exogenous progestin can delay parturition

Toxicity and overdose

Generally well tolerated at label doses. INJECTION-SITE reactions: sterile abscess, oily granuloma at the IM site (oily vehicle) — rotate sites. Hepatic enzyme elevation on chronic high-dose use. Mammary gland stimulation (rare swelling). Behavioural anoestrus during therapy. Persistent CL formation may delay return to oestrus after discontinuation. Cushingoid-like signs at high doses in dogs (rarely used).

Management: No specific antidote. Discontinue. Supportive: hepatic protection (SAMe) if hepatic enzymes elevated. Most overdoses well tolerated; return to oestrus may take 2–8 weeks after discontinuation due to depot effect. Injection-site abscess: drain if fluctuant, NSAID for pain.

Clinical pearls

• Bovine habitual / threatened abortion: 500–1000 mg IM weekly through critical gestation window (typically months 2–7)
• Mare threatened abortion / luteal insufficiency: 500–1500 mg IM weekly under specialist supervision — verify progesterone deficiency first
• Goat / sheep doe threatened abortion: 100–250 mg IM weekly
• CONFIRM PREGNANCY before each dose — non-pregnant females will be anti-fertility
• DEEP IM ONLY (oily vehicle) — rotate sites every week to prevent sterile abscess
• Discontinue 1–2 weeks before expected parturition to allow normal labour
• Not effective for habitual abortion of infectious aetiology — investigate cause (Brucella, Leptospira, BVDV) before progestin therapy
• Long depot duration — return to cyclicity may take 2–8 weeks after final dose

Mechanism of action

Long-acting synthetic progestin (17α-hydroxyprogesterone esterified with caproic acid → slow IM release over 7–14 days). Binds progesterone receptors in the myometrium and endometrium → suppresses uterine contractility, maintains endometrial decidualisation, and supports placental function. Reduces gonadotrophin (LH) release via negative feedback on the hypothalamus / pituitary → prevents oestrus cycling. Used to prevent abortion in mares / cows with low endogenous progesterone or repeated pregnancy losses.

Formulations and products

• Progesyn 250 mg/mL injection (Intas, 3 mL ampoule)
• Progesyn (Intas (Neovet)) — 250 mg/mL, Oily IM injection
• Progress-Sure (Assure Biotech, Jagadhri (HR)) — Hydroxyprogesterone caproate 250 mg/mL - 750 mg per 3 mL ampoule, Oily injection - ampoule with 3 mL syringe and 21G needle
• A-Progen (Assure Biotech, Jagadhri (HR)) — Progesterone IP (micronised) 75 mg per 3 mL, Oily injection

Storage

Oily injection (Progesyn): 15–25 °C, do NOT refrigerate (oil thickens). Protect from light. Multidose vial: 28 days after broaching, sterile technique mandatory.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other hormones, emergency drugs, supplements and other drugs

• Heparin (Unfractionated)
• Hetastarch (Hydroxyethyl Starch)
• Human Chorionic Gonadotrophin (hCG)
• Hydrocortisone (Cortisol)
• Hydroxyzine
• Hypertonic Saline (7.2–7.5% NaCl)
• Imepitoin
• Insulin

Frequently asked questions