Labeled Indications:

Contraception (104 mg per 0.65 mL and 150 mg/mL injection): Medroxyprogesterone acetate is used to prevent pregnancy in females who are of reproductive potential.[1]

Amenorrhea, secondary (tablet): When women are experiencing amenorrhea due to hormonal imbalance and not because of organic pathologies such as fibroids and uterine cancer.[2]

Abnormal uterine bleeding (tablet): The drug is indicated for women who are experiencing abnormal bleeding due to hormonal imbalance and not because of organic pathologies such as fibroids and uterine cancer.

Endometrial hyperplasia prevention (tablet): Medroxyprogesterone acetate is administered to non-hysterectomized postmenopausal patients who are receiving a daily oral dose of estrogen 0.625 mg.[3]

Endometrial carcinoma (400 mg/mL injection) (100 mg tablet): In patients who have inoperable, recurrent and/or metastatic endometrial carcinoma, medroxyprogesterone acetate is used as adjunctive and/or palliative treatment.[3]

Endometriosis (104 mg/0.65 mL injection): Used in patients experiencing pain related to endometriosis.[4]

Off-Label Indications: 

• Acute abnormal uterine bleeding[5]
• Endometrial hyperplasia 
• Hot Flashes 
• Paraphilia/Hypersexuality[6]

Medroxyprogesterone acetate (MPA), a progestin, is similar in structure to naturally-occurring progesterone. The mechanism of action of progestin involves binding the progesterone receptor in the hypothalamus, female reproductive tract, and the pituitary and inhibiting the secretion of gonadotropin-releasing hormone (GnRH). By decreasing the frequency of release of GnRH, MPA blunts the midcycle LH surge and prevents follicular maturation and ovulation. In the endometrium, MPA changes a proliferative endometrium to a secretory one, which makes it difficult for implantation. Finally, MPA also impairs sperm migration into the uterus by increasing the viscosity of the cervical mucus.[1]

In premenopausal women experiencing amenorrhea and irregular uterine bleeding, MPA can be used to establish a normal menstrual cycle. MPA also decreases the endometrial growth in postmenopausal women and menopausal women who receive estrogen therapy. In patients with endometriosis, MPA acts on endometrial lesions and decreases endometrial related pain.[4]

Three percent of the users experienced an unintended pregnancy, and efficacy was determined to be 99%. Manufacturers recommend not using MPA until six weeks postpartum in breastfeeding women as infants can suffer exposure through breast milk.[7] Women with sickle-cell disease are considered good candidates for MPA. MPA has shown to reduce sickle cell pain in women.[8] It is also considered to have decreased incidences of seizures in women with seizure disorders.[2] Medroxyprogesterone, due to its association with respiratory centers, has been used to treat patients with COPD, hypercapnia, sleep apnea, and Pickwickian syndrome.[9]

Pharmacodynamics & Pharmacokinetics:

• Absorption:
  • Oral: Rapid
  • IM: Slow
• Protein binding: 86% to 90% bound to albumin [4]
• Metabolism: Hepatic through hydroxylation and conjugation. 
• Bioavailability: 0.6% to 10%. 
• Half-Life Elimination: [10]
  • Oral: 12 to 17 hours
  • IM: approximately 50 days
  • SubQ: approximately 43 days
• Time to Peak 
  • Oral: 2 to 7 hours [11]
  • IM: 3 weeks to reach Cmax of 1 to 7 ng/mL [4]
  • SubQ: 1 week to reach Cmax of 0.953 ng/mL[4]
• Excretion: Urine as glucuronide conjugates with a small amount excreted as sulfates. 

In vitro, MPA is metabolized by CYP3A4. Therefore, inducers and inhibitors of CYP3A4 can affect the metabolism of MPA. [12]

MPA inhibits ovulation for 14 weeks and must be administered every three months (12 weeks) for continuous contraception. Administration can be either intramuscular (IM) or subcutaneous. MPA formula is available in a 150 mg/ml injection vial or a prefilled syringe for IM injections. Severe adverse reactions can occur if administered IV.

 Oral Administration

• MPA tablets can be ingested sublingually and with no regard to meals. 

Injectable Administration

• Inspect the product for discoloration and particulate matter before usage. 

Intramuscular Administration 

 (Contraceptive injection suspension:)

• The injection must be administered to the gluteal or the deltoid region. 
• Before injecting, shake the suspension. 
• Before injecting, do not dilute the suspension. 
• The injection must not be administered IV. 
• It is important to exclude the possibility of pregnancy, especially if 14 weeks have passed since the first dose. 

Subcutaneous Administration [13]

 Contraceptive Injection suspension: 

• Inject prefilled syringe into the anterior thigh or abdomen at a 45-degree angle. Pull the skin away from the body before injecting the drug. 
• Shake the tube vigorously for 1 min before usage. 
• After injecting, press the area lightly but do not rub. 
• Avoid giving this intramuscularly (IM) or intravenously (IV).
• Must be administered within five days of onset of menstrual bleeding. 

Menstrual irregularities and weight gain are the most common adverse effect of using MPA.[14] In terms of weight gain, a study reported that MPA resulted in an increase of 1.61 in BMI and an average weight gain of 3.23 kg (7.11 lb).  [15] Meanwhile, 57.3% of the patients who were received medroxyprogesterone reported irregular menses during the first year. Irregular bleeding decreases to 30% after 24 months and then to 10% thereafter. Fifty-five percent of women report amenorrhea after 12 months of therapy, and that number goes up to 68% after two years. The following adverse effects for medroxyprogesterone contraceptive injection have been noted: oligomenorrhea, delayed return to fertility, prolonged anovulation (temporary infertility), unexpected pregnancy, uterine hyperplasia, genitourinary infections, vaginal cysts, vaginal hemorrhage, and uterine hemorrhage. (Medroxyprogesterone acetate 104 mg/0.65ml) injection suspension package insert. In females for hormone replacement therapy who utilize medroxyprogesterone tablets without estrogen, the following adverse effects have presented: bleeding, spotting, changes in menstrual flow, changes in cervical erosion, and changes in cervical secretions. 

 Both genders reported experiencing changes in breast and sexual function. Females who used the medroxyprogesterone contraceptive injection reported breast pain (2.8%) and a decreased libido (5.5%). Post-market reports with the injection usage determined other adverse effects such as breast lumps, changes in breast size, nipple bleeding, galactorrhea, dyspareunia, lactation suppression, and changes in libido.[16] Females, who only use medroxyprogesterone (without estrogen) for hormone replacement therapy, reported mastodynia or mastalgia (breast pain), galactorrhea, and breast tenderness. As for patients who used medroxyprogesterone in addition to estrogen for hormone replacement therapy, they reported breast tenderness, nipple breast discharge, fibrocystic breast changes, and breast cancer. In males, there were reports of impotence and a decrease in testosterone levels by 25% when they received medroxyprogesterone for palliative reasons. 

Angioedema, anaphylactic shock, and dermatologic reactions have been reported in users. Between 1 and 5% of the medroxyprogesterone users reported hot flashes and acne vulgaris. Alopecia was reported in 1.1% of patients who received the contraceptive injections. Postmarketing reports of contraceptive injection recipients indicated the following adverse effects: angioedema, dry skin, increased body odor, hyperhidrosis, axillary swelling, melasma, scleroderma, and urticaria. In women who used medroxyprogesterone in addition to estrogen for hormone replacement therapy, the following adverse effects occurred: chloasma or melasma after discontinuation, erythema multiforme, erythema nodosum, and alopecia. 

Patients utilizing medroxyprogesterone contraceptive injections  have reported dizziness (5.6%), insomnia (1% to 5%), nervousness (10.8%), depression (1% to 5%), anxiety or irritability (1% to 5%) and headaches (9% to 16.5%). If a patient experiences headache or migraine with focal features that are consistent with cerebral ischemia, then discontinuation of medroxyprogesterone is recommended. [17] CNS side effects such as facial palsy, syncope, paralysis, and paresthesia have also occurred with the contraceptive injection usage. Women utilizing medroxyprogesterone tablets along with estrogen, chorea, and mood disturbances may occur. 

Women utilizing the IM depot contraceptive injection reported gastrointestinal effects such as abdominal pain, nausea, and bloating. Recipients of the subcutaneous contraceptive injections  

Progestins stimulate the respiratory center and, as a result, during pregnancy as well as the luteal phase of the menstrual cycle in women. MPA can cause women to hyperventilate and become hypocapnic due to elevated levels of endogenous progestins.

A study conducted in Thailand reported that pregnant women who took MPA had infants with polysyndactyly. The study also determined that the infants of these mothers were at an increased risk of having chromosomal abnormalities.[2]

The drug is not recommended for women considering pregnancy in the near future as it may delay the return of fertility after discontinuation. Medroxyprogesterone is contraindicated in patients with known hypersensitivity to medroxyprogesterone acetate. Cases of angioedema and anaphylactic reaction have occurred in patients utilizing medroxyprogesterone. Both forms of the drug (oral and injection) are contraindicated in patients with pre-existing breast cancer. In patients with a history of breast cancer, renal cancer, endometrial cancer, or a family history of breast cancer, medroxyprogesterone is contraindicated. Medroxyprogesterone injection has shown to have a slightly increased risk of developing breast cancer.[18][19][20]

Medroxyprogesterone use requires caution in patients with diabetes mellitus. Hormonal contraceptives have known to alter insulin sensitivity and, as a result, glucose tolerance. Medroxyprogesterone injections are contraindicated in patients with a history of arterial or venous thromboembolic diseases or patients with increased risks for stroke, heart disease, and arterial vascular disease.[17] Hormonal contraceptives can cause fluid retention and, as a result, should be used with caution in patients with asthma, congestive heart failure, and nephrotic syndrome. 

When using medroxyprogesterone in postmenopausal women along with estrogen therapy, it is associated with cardiovascular and thromboembolic risks.[2] Medroxyprogesterone use requires caution in women with hypertension, and blood pressure should be monitored regularly. Even though estrogen-progestin combinations are known to alter serum lipid levels, it is essential to be cautious about medroxyprogesterone, a progestin-only contraceptive. Therefore, providers should check HDL and LDL regularly in patients. Although no birth defects have been noted in patients exposed to medroxyprogesterone, it is contraindicated in pregnancy or suspected pregnancy. At higher concentrations, the suspension injections can induce temporary infertility, and patients experience delays in returning to baseline after stopping the treatment. Medroxyprogesterone tablets are also contraindicated in patients with incomplete abortions. In women with hepatic dysfunction or hepatic diseases, medroxyprogesterone usage is contraindicated. Usage should be discontinued in women who experience jaundice or disturbances with their liver function.   

 In women with a history of major depression, migraine, or seizure disorder, medroxyprogesterone should be used with caution as progestin can exacerbate these conditions. 

Providers should counsel patients that the usage of medroxyprogesterone does not protect against human immunodeficiency virus (HIV) infection or other sexually transmitted diseases.[21]

Additionally, as stated in a boxed warning on medroxyprogesterone depot injections, medroxyprogesterone usage can alter the bone mineral density and may not be reversible in premenopausal women. Recommendations for patients include taking calcium and vitamin D when using medroxyprogesterone depot-injections.[22]