Methenolone Enanthate 100 mg/ml

Methenolone Enanthate 100 mg/ml (Metenolone (methenolone)) · ATC A14AA04

Anabolic steroid · long-acting ester

Each 1 ml contains Methenolone Enanthate 100 mg in a sterile oil carrier.

For the full list of excipients, see section 6.1.

Solution for injection in a single-use glass ampoule for deep intramuscular use.

Therapeutic indications

Anabolic therapy with a mild androgenic profile, as determined by a physician.

Posology and method of administration

Deep intramuscular injection as directed by a physician. Not for intravenous use. Rotate injection sites. Dose and interval are individualised by the prescriber.

Contraindications

Known hypersensitivity to the active substance or excipients. Known or suspected carcinoma of the prostate or male breast. Not for use in women, in pregnancy or while breastfeeding. Use with caution in cardiac, renal or hepatic impairment.

Special warnings and precautions for use

Keep out of the reach and sight of children. Contains a substance prohibited in sport (WADA).

Interaction with other medicinal products

Coumarin anticoagulants

Anabolic steroids increase sensitivity to oral anticoagulants and may substantially prolong prothrombin time and INR, with a risk of bleeding; coagulation monitoring and prescriber-determined dose adjustment are necessary on initiation and withdrawal.

Insulin and oral hypoglycaemic agents

Enhanced insulin sensitivity may reduce blood glucose and increase the risk of hypoglycaemia; glycaemic control should be monitored and antidiabetic therapy reviewed by the prescriber.

Ciclosporin

Concomitant androgen administration may raise ciclosporin concentrations and increase the risk of nephrotoxicity; monitoring of trough concentrations and renal function is advised.

Corticosteroids and corticotrophin

Additive sodium and water retention, with an increased risk of oedema in patients with cardiac, hepatic or renal disease; a countervailing pharmacodynamic interaction on protein catabolism is also recognised, methenolone opposing the catabolic effects of glucocorticoids.

Erythropoiesis-stimulating agents

Additive stimulation of erythropoiesis with an increased likelihood of excessive haemoglobin rise and erythrocytosis; haematocrit requires monitoring when the two are combined.

Use in special populations

Pregnancy and breastfeeding

Contraindicated. Anabolic steroids cross the placenta and may virilise a female foetus. Women of childbearing potential must use effective contraception during treatment. Data on excretion into human milk are lacking and breastfeeding is not recommended.

Paediatric population

Use in children and adolescents requires specialist supervision. Anabolic steroids accelerate bone maturation ahead of linear growth and may cause premature epiphyseal closure and irreversible short stature; bone age should be assessed radiologically at intervals determined by the prescriber, and virilising effects monitored.

Elderly

Elderly male patients require assessment for prostatic hyperplasia and occult prostatic carcinoma before and during treatment; androgens are contraindicated in carcinoma of the prostate or of the male breast. Haematocrit and blood pressure should be monitored, as erythrocytosis and fluid retention are less well tolerated in this group.

Renal impairment

Caution is required; sodium and water retention may aggravate oedema, hypertension or cardiac failure. No dedicated pharmacokinetic studies have been performed in renal impairment, and the regimen remains as determined by the prescriber with monitoring of weight, blood pressure and electrolytes.

Hepatic impairment

Contraindicated in severe hepatic impairment; in mild to moderate impairment, clearance of methenolone may be reduced and liver function should be monitored, although the hepatic risk of this non-alkylated parenteral ester is materially lower than that of 17-alpha-alkylated oral agents.

Athletes

Methenolone is prohibited at all times, in and out of competition, under class S1.1a (exogenous anabolic androgenic steroids) of the World Anti-Doping Agency Prohibited List. Its characteristic urinary metabolites are readily identified by accredited laboratories and remain detectable for a prolonged period after the last injection of the enanthate depot. Athletes subject to anti-doping regulation must not use this product without a granted therapeutic use exemption.

Undesirable effects

Endocrine

Dose-related suppression of luteinising hormone and follicle-stimulating hormone with reduced endogenous testosterone secretion, testicular atrophy, oligospermia and impaired fertility; in women, virilisation with hirsutism, voice deepening, clitoral enlargement and menstrual irregularity, although androgenic reactions are generally less pronounced than with more strongly androgenic androstane derivatives

Blood and lymphatic system

Increased haemoglobin, haematocrit and red cell mass; erythrocytosis with increased blood viscosity on prolonged exposure; changes in coagulation parameters

Skin and subcutaneous tissue

Acne, seborrhoea, increased sweating, hirsutism, exacerbation of androgenetic alopecia in predisposed individuals

Investigations and metabolism

Decreased high-density lipoprotein cholesterol and increased low-density lipoprotein cholesterol, suppression of sex hormone-binding globulin, mild fluid and sodium retention, altered total thyroid hormone concentrations secondary to reduced thyroxine-binding globulin

Hepatobiliary

Occasional transient elevation of transaminases; the absence of 17-alpha-alkylation and the parenteral route mean that cholestatic jaundice, peliosis hepatis and hepatic tumours are rarely encountered, in contrast to the 17-alpha-alkylated oral anabolic steroids

Cardiovascular

Hypertension, peripheral oedema; with sustained high exposure, adverse cardiac remodelling including left ventricular hypertrophy

Psychiatric and nervous system

Irritability, aggression, mood alteration, insomnia, headache; depressed mood and reduced libido on withdrawal of prolonged treatment

General disorders and administration site conditions

Injection site pain, induration and erythema related to the oily carrier; rarely sterile abscess; very rarely cough or transient dyspnoea immediately after injection suggestive of pulmonary oil microembolism

Overdose

Single-dose overdose is unlikely to result in acute systemic toxicity; the clinical picture is an amplification of the recognised endocrine, haematological and metabolic effects, notably erythrocytosis and androgenic reactions. There is no specific antidote. Treatment consists of discontinuation with symptomatic and supportive management, including monitoring of haematocrit, liver function, lipids and gonadal axis recovery, which may take several weeks in view of the prolonged depot release; venesection may be considered where the haematocrit is markedly raised.

Pharmacodynamic properties

Methenolone enanthate is the enanthate ester of methenolone, 1-methyl-5-alpha-androst-1-en-17-beta-ol-3-one, an anabolic steroid of the androstane series derived from dihydrotestosterone. Methenolone is a partial agonist at the androgen receptor with modest anabolic potency and comparatively low androgenic activity relative to testosterone; receptor binding promotes nitrogen retention, protein synthesis and, through stimulation of renal erythropoietin production and direct effects on erythroid progenitors, an increase in erythropoiesis, which underlay its historical investigation in anaemias associated with bone marrow failure and in catabolic and wasting states. The 1-methyl and 1,2-double bond substitutions retard inactivation of the 3-keto group by hydroxysteroid dehydrogenases. The saturated 5-alpha configuration means methenolone is neither a substrate for aromatase nor for 5-alpha-reductase, so no oestrogenic metabolites are produced and it has no progestogenic activity; it is not 17-alpha-alkylated. Endogenous gonadotrophin secretion is nevertheless suppressed in a dose-dependent manner.

Pharmacokinetic properties

After deep intramuscular injection the oily depot releases methenolone enanthate slowly, absorption being the rate-limiting step; the ester is cleaved by non-specific plasma and tissue esterases to methenolone and enanthic acid. Serum concentrations of the free steroid rise over several days, with peak concentrations typically 3 to 5 days after injection and a pharmacological effect maintained for approximately two weeks. Methenolone is extensively protein bound, principally to albumin and, to a lesser degree than dihydrotestosterone, to sex hormone-binding globulin, so the free fraction is relatively higher than for more avidly SHBG-bound androstane derivatives. Metabolism is hepatic and proceeds by reduction of the 3-keto group and hydroxylation, the principal urinary metabolite being 3-alpha-hydroxy-1-methylene-5-alpha-androstan-17-one; metabolites are excreted in urine largely as glucuronide conjugates. The apparent terminal half-life, dominated by depot release, is approximately 10 days.

List of excipients

Benzyl alcohol (E 1519) 20 mg (co-solvent and antimicrobial preservative), all-rac-α-tocopherol (E 307) 1 mg (antioxidant), refined oil carrier q.s. to 1 ml. The oil carrier is a pharmacopoeial refined vegetable oil for parenteral use complying with the current Ph. Eur./USP monograph for peroxide value and acid value.

Excipient warnings

This medicinal product contains 20 mg benzyl alcohol in each 1 ml ampoule. Benzyl alcohol may cause allergic reactions and local irritation at the injection site. It must not be given to newborn infants (up to 4 weeks of age) and should not be used for more than one week in infants and children under 3 years of age without medical advice, because of the risk of severe adverse reactions including metabolic acidosis and gasping syndrome. Ask a doctor or pharmacist for advice if you are pregnant or breast-feeding, or if you have liver or kidney impairment. This medicinal product also contains a refined vegetable oil carrier; rare hypersensitivity reactions to vegetable oils used as injection vehicles have been reported, and it must not be used in patients with known hypersensitivity to the oil carrier.

Incompatibilities

In the absence of compatibility studies, this medicinal product must not be mixed with other medicinal products. The oil vehicle is immiscible with aqueous injections and infusion solutions; the product must not be diluted, drawn into a syringe with other injections, or given intravenously. For deep intramuscular injection only.

Shelf life

36 months from the date of manufacture in the unopened container. Do not use after the expiry date stated on the ampoule and carton; the expiry date refers to the last day of that month.

After first opening

Single-use ampoule. Use immediately after opening; the dose is withdrawn once and the ampoule discarded. No residual solution may be kept for a subsequent dose. Inspect the solution before use — it should be clear and free from visible particulate matter; do not use if the solution is cloudy or if the ampoule is cracked or has been previously opened.

Storage

Store below 25 °C. Protect from light. Do not freeze. Keep ampoules in the outer carton until use.

Container

Clear or amber USP/Ph. Eur. Type I borosilicate glass one-point-cut ampoule, 1 ml nominal fill, sealed by fusion under classified aseptic conditions. Ten ampoules in a moulded tray inside a printed folding carton with the package leaflet; the carton carries a GS1 DataMatrix encoding GTIN, batch, expiry and unique serial number, and a scratch-off verification panel. Primary packaging components are controlled under ISO 15378. Pack size: 10 ampoules × 1 ml.

Disposal

Any unused medicinal product or waste material should be disposed of in accordance with local requirements. Used and unused ampoules, needles and syringes must go directly into an approved rigid sharps container; broken glass must not be placed in domestic waste and the oil solution must not be emptied into drains or wastewater.

Pack

10 Ampoules × 1 ml

GTIN

05012345678904

Serial

5582 1190 4471 04

LOT

ME2604D

MFG

04 / 2026

EXP

04 / 2029

Every carton carries a GS1 DataMatrix and a verification code; a pack can be checked at ergopharm.net/verify.

Ergopharm Advanced Research Centre, Tandalja, Vadodara, Gujarat 390012, India. For Export Only.

Report a suspected adverse reaction or quality defect to pv@ergopharm.net.