Oxandrolone Capsules

Generic Name:

Oxandrolone

Brand Name Equivalent:

Anavar®

Overview of Oxandrolone Capsules

Dosage Strengths of Oxandrolone Capsules

5 mg
15 mg
25 mg
50 mg

General Information

Oxandrolone is an orally-administered synthetic testosterone derivative. Its anabolic effects are greater than its androgenic effects due to the deletion of the methyl group from the C-19 position. The anabolic potency of oxandrolone is approximately 3 to 13 times that of testosterone and methyltestosterone. In combination with adequate calories, oxandrolone is useful for promoting weight gain after burns or trauma and in certain disease states such as COPD and AIDS. The increase in weight is primarily a result of enhanced lean body mass as compared to enhanced body fat often seen with nutritional supplementation. The beneficial effects on lean body mass are lost with drug discontinuance. Oxandrolone is used to help offset protein catabolism associated with prolonged corticosteroid use. Supportive data also exist for the treatment of patients with Duchenne's muscular dystrophy, constitutional delay of growth and puberty, HIV wasting syndrome and associated muscle weakness, and short stature associated with Turner's syndrome. Conflicting evidence exists as to whether or not anabolic steroids significantly increase athletic performance by increasing muscle strength, but the NCAA and IOC currently prohibit their use by athletes. Oxandrolone is not ergogenic at labeled doses but athletes often use higher doses; athletic use should be discouraged due to the risk for dyslipidemia, potential hepatotoxicity, and other serious side effects. Oxandrolone was approved by the FDA in July 1964 and became a controlled substance in 1991.

Mechanism of Action

Oxandrolone promotes skeletal muscle protein synthesis through a direct stimulant effect on testosterone or dihydrotestosterone receptors and through increased androgen receptor expression in skeletal muscle and intracellular amino acid reutilization. Oxandrolone binds to the same intracellular receptors in the reproductive tract, bone, skeletal muscle, brain, liver, kidney, and adipocytes as testosterone and dihydrotestosterone. Receptor binding results in gene expression regulation.

Oxandrolone works directly as an androgen, as it cannot be aromatized to estrogen. In addition to myotrophic effects from androgen receptor interaction in skeletal muscle, it appears that testosterone and oxandrolone have myotrophic effects caused by decreased protein catabolism through interaction with glucocorticoid receptors. It is hypothesized that anabolic-androgenic steroids displace glucocorticoids bound to the glucocorticoid receptor. Another hypothesis is that anabolic-androgenic steroids interfere with the glucocorticoid response element (DNA binding region). Improvement in lean body mass is a result of the drug's myotrophic effect. Unlike growth hormone, which causes irreversible hyperplasia, anabolic steroids cause hypertrophy, a reversible event.

In addition to protein synthesis in muscle, increases in serum albumin, prealbumin, and transferrin concentrations have been noted with oxandrolone. Increased erythrocyte production is apparently due to enhanced production of erythropoietic stimulating factor.

Oxandrolone also causes osteolytic bone resorption stimulation, osteoblast proliferation, bone matrix protein production, and synthesis of growth factor and cytokines, which are mediated by androgen receptors on osteoblasts. These effects on bone are responsible for the growth promoting effects of oxandrolone.

Oxandrolone causes suppression of pituitary gonadotrophins through negative feedback. Thus, endogenous testosterone production is inhibited with oxandrolone due to inhibition of luteinizing hormone. Oxandrolone can also suppress follicle-stimulating hormone release via negative feedback inhibition. Furthermore, oxandrolone may exert a direct effect on the testes. Oxandrolone lowers HDL by induction of hepatic triglyceride lipase, an enzyme that catabolizes HDL.

Pharmacokinetics

Oxandrolone is only administered orally. Plasma protein binding is 94—97%. Due to the 17-alpha-alkylation and absence of a 4-ene function in ring A, hepatic inactivation of oxandrolone is markedly retarded as compared to testosterone and other anabolic-androgenic steroids. Metabolism occurs in the liver by hydroxylation and sulfation, although the extent of hepatic inactivation is less with oxandrolone compared with other anabolic-androgenic steroids. The reduced metabolism results in a longer elimination half-life (9.4 hours) and higher peak plasma concentrations than 17-2-methyltestosterone. Approximately 28% of an oral dose is excreted unchanged. Excretion of the parent drug and metabolites occurs primarily in the urine as unconjugated products.

Route-Specific Pharmacokinetics:

Oral Route: Absorption of oxandrolone is rapid and almost complete with an oral bioavailability of 97%.

Special Populations:

Elderly: The mean elimination half-life is prolonged to 13.4 hours in elderly patients; however, time to peak, peak plasma concentration, or AUC does not differ significantly between elderly and younger adult patients.

For the treatment of cachexia, and as adjunct therapy to promote weight gain and protein anabolism after weight loss following extensive surgery, chronic infections, severe trauma, or prolonged administration of corticosteroids, and in some patients who without definite pathophysiologic reasons fail to gain or to maintain normal weight:

NOTE: Adequate caloric and protein consumption is required.

Oral dosage: Adults: 2.5 mg PO 2—4 times per day; however, a range from 2.5—20 mg PO per day may be necessary. The usual duration of therapy is 2—4 weeks, which may be repeated as needed. The dose and duration will depend upon the efficacy and tolerability observed.

Geriatric: The recommended dose is 5 mg PO twice daily. The usual duration of therapy is 2—4 weeks, which may be repeated as needed. The dose and duration will depend upon the efficacy and tolerability observed.

Children: 0.1 mg/kg or less (0.045 mg per pound or less) of body weight PO per day (not to exceed the adult dosage). The usual duration of therapy is 2—4 weeks, which may be repeated as needed. The dose and duration will depend upon the efficacy and tolerability observed.

Route-Specific Administration:

Oral Administration: Oxandrolone can be administered without regard to meals. Adequate caloric and protein consumption is required when anabolic steroids are used in the management of cachexia.

Contraindications/Precautions

Oxandrolone is contraindicated in pregnancy and is classified in FDA pregnancy risk category X. Masculinization of the fetus, infertility and teratogenic effects, including embryotoxicity and fetotoxicity, have been reported in female animal offspring when oxandrolone was given in doses 9-times the human dose. These are effects consistent with known effects of other anabolic and androgenic hormones. Oxandrolone should be used cautiously in females of child-bearing potential who may become pregnant. If oxandrolone is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.1

It is unknown if oxandrolone is excreted into breast milk. Nursing discontinuation or oxandrolone cessation is recommended for mothers who are breast-feeding.1 Oxandrolone is a synthetic testosterone derivative. Significant exposure to this androgen via breast-feeding may have adverse androgenic effects on the infant and the drug may also interfere with proper establishment of lactation in the mother.2 Historically, testosterone/androgens have been used adjunctively for lactation suppression.2 Alternative methods to breast-feeding are recommended in lactating women receiving anabolic/androgenic therapy.

Androgen therapy can result in hypoglycemia in patients with diabetes mellitus. Oxandrolone can inhibit the metabolism of oral antidiabetic agents and some androgens can lower blood glucose in patients with diabetes. Close monitoring of blood glucose concentrations in patients with diabetes mellitus taking oxandrolone is recommended.

In general, the use of androgens in children should be undertaken only with extreme caution; growth suppression as a result of accelerated bone maturation may occur. The risk of compromised adult growth is greater with oxandrolone use in younger aged patients. X-ray examination of bone age every six months is recommended while on oxandrolone. Of note, anabolic-androgenic steroids can increase height without significantly affecting bone age. Completion of epiphyseal fusion leading to growth cessation does not occur with oxandrolone since it is not aromatized into substances with estrogenic properties.

Oxandrolone can stimulate the growth of cancerous tissue and is contraindicated in male patients with known prostate cancer or breast cancer. Patients with prostatic hypertrophy should be treated with caution because of the possible development of malignancy. Periodic assessment of prostate specific antigen is recommended for older patients.

Oxandrolone is contraindicated in patients with primary or secondary hypercalcemia due to osteolytic bone resorption stimulation. The risk of androgen-induced hypercalcemia is higher in immobile patients and in those with metastatic breast cancer. Frequent determination of serum and urine calcium concentrations is recommended in immobile patients and in females with breast cancer. Oxandrolone is contraindicated in females with breast cancer who have hypercalcemia.

Alterations in the serum lipid profile consisting of decreased HDL and increased LDL occur with oxandrolone. The drug should be used cautiously in patients with hypercholesterolemia and in those with cardiac disease especially in those with arteriosclerosis, coronary artery disease and myocardial infarction. Monitoring of lipoprotein concentrations is recommended during oxandrolone therapy. During treatment with androgens, edema can occur because of sodium retention. Thus, this another reason to use oxandrolone cautiously in patients with heart failure, peripheral edema, or severe cardiac disease.

Oxandrolone should be used cautiously, if at all, in patients with pre-existing hepatic disease or cholestasis. Androgenic-anabolic steroids have been associated with the development of certain types of hepatic disease including peliosis hepatis (blood filled cysts in the liver and sometimes splenic tissue), benign and malignant liver tumors (e.g., hepatocellular cancer), cholestatic hepatitis, and jaundice. Rarely, hepatic failure has occurred. Baseline liver function tests and exclusion of preexisting liver disease is recommended prior to oxandrolone initiation, and periodic liver function test assessment is suggested while on therapy, particularly for adult patients 65 years of age and older. During treatment with androgens, edema can occur because of sodium retention. This is another reason to use oxandrolone cautiously in patients with severe hepatic disease.1

During treatment with androgens, edema can occur because of sodium retention. Due to the possible fluid retention, oxandrolone is contraindicated in patients with severe renal disease. Patients with heart failure, nephrosis or nephrotic phase of nephritis, or peripheral edema should be treated with caution.

Oxandrolone at doses of 5 or 10 mg twice daily has been studied in 4 clinical trials involving a total of 339 patients with 172 of these patients 65 years of age or older. Mean weight gain was similar between geriatric and younger adults, with no differences in efficacy found between the 2 dosages; however, elderly patients (particularly elderly women), were more likely to experience fluid retention and elevations in hepatic transaminases (LFTs). Based on these data and because the half-life of oxandrolone is prolonged in this patient population, the manufacturer recommends using a lower dose when treating geriatric patients.1 The federal Omnibus Budget Reconciliation Act (OBRA) regulates the use of medications in residents of long-term care facilities. According to the OBRA guidelines, use of appetite stimulants should be reserved for situations where assessment and management of underlying correctable causes of anorexia and weight loss are not feasible or successful, and after evaluating the potential benefits versus risks. Appetite and weight should be monitored at least monthly and the appetite stimulant should be discontinued if there is no improvement. Possible adverse effects of oxandrolone include fluid retention, excessive sexual stimulation, virilization of females, and feminization of males.3

Oxandrolone should generally be avoided in patients with polycythemia, as oxandrolone, especially in high doses, can cause further increases in the red cell mass. Periodic assessment of hemoglobin and hematocrit is recommended.

Pregnancy

Oxandrolone is contraindicated in pregnancy and is classified in FDA pregnancy risk category X. Masculinization of the fetus, infertility and teratogenic effects, including embryotoxicity and fetotoxicity, have been reported in female animal offspring when oxandrolone was given in doses 9-times the human dose. These are effects consistent with known effects of other anabolic and androgenic hormones. Oxandrolone should be used cautiously in females of child-bearing potential who may become pregnant. If oxandrolone is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.1

Breast-feeding

It is unknown if oxandrolone is excreted into breast milk. Nursing discontinuation or oxandrolone cessation is recommended for mothers who are breast-feeding.1 Oxandrolone is a synthetic testosterone derivative. Significant exposure to this androgen via breast-feeding may have adverse androgenic effects on the infant and the drug may also interfere with proper establishment of lactation in the mother.2 Historically, testosterone/androgens have been used adjunctively for lactation suppression.[fn]Kochenour NK. Lactation suppression. Clin Obstet Gynecol. 1980;23:1045-1059. Alternative methods to breast-feeding are recommended in lactating women receiving anabolic/androgenic therapy.

Adverse Reactions/Side Effects

Oxandrolone associated hepatotoxicity may be due to the development of peliosis hepatis, hepatoma formation leading to cholestasis and jaundice, or direct hepatic necrosis. The 17a-alkylation appears to be the etiology for hepatic effects with the exception of peliosis hepatis, which has also been seen with testosterone. The mechanism of peliosis hepatis development is unknown and there does not appear to be a dose or duration relationship. Jaundice due to cholestasis is dose and duration related; its development is rare with recommended use. Oxandrolone cessation usually resolves peliosis hepatis as well as jaundice. Hepatoma regression or growth cessation usually occurs with oxandrolone cessation, as the majority of tumors are benign and androgen dependent. However, hepatomas associated with androgens or anabolic steroids are much more vascular than other hepatic tumors and may be undetected until life-threatening intra-abdominal hemorrhage develops. Hepatocellular carcinoma has been associated rarely with long-term, high-dose anabolic steroid therapy and also may regress with drug cessation. Baseline liver function tests and exclusion of preexisting liver disease is recommended prior to therapy initiation. Underlying liver disease and concomitant use of other hepatotoxic drugs may potentiate or increase the severity of liver toxicity. Elderly patients may experience elevated hepatic enzymes more commonly than younger adults; a lower dose is recommended in elderly patients. Periodic assessment of liver function tests in all patients while on oxandrolone with drug discontinuation upon hepatic disease development is recommended. Other manifestations of hepatotoxicity can include elevated hepatic enzymes, hepatitis, or hepatic failure.1

The androgenic effects of oxandrolone can affect both males and females. Manifestations include acne vulgaris, clitoromegaly, hirsutism, libido increase, penile enlargement, priapism, CNS depression, and CNS excitability including insomnia. Excessive sexual stimulation is more likely in geriatric males. Because irreversible virilization of women can occur, oxandrolone should be discontinued with the development of voice deepening or hoarseness, hirsutism, acne, or clitoromegaly. Estrogen supplementation does not prevent oxandrolone induced virilizing changes and some changes may persist despite prompt drug discontinuation. Menstrual irregularity, amenorrhea, or oligomenorrhea can occur due to oxandrolone-induced suppression of gonadotropins.1

Peripheral edema can occur with oxandrolone as the result of increased fluid retention (in association with sodium retention/ hypernatremia) and is manifested by weight gain. In the treatment of patients with impaired renal function or congestive heart failure, the fluid retention is of greater clinical significance. Elderly patients may be more likely to experience fluid retention when compared to younger adult patients; a lower dose is recommended in elderly patients. Other serum electrolytes (i.e., calcium (hypercalcemia), phosphate (hyperphosphatemia), and potassium (hyperkalemia)) are also retained. Hypercalcemia can also be a result of the stimulatory effect of oxandrolone on osteolytic bone resorption.1

Prostate cancer as a secondary malignancy or prostatic hypertrophy can develop during prolonged therapy with oxandrolone especially in elderly men. Periodic assessment of prostate specific antigen is recommended especially for geriatric patients. Signs of acute epididymitis (e.g., fever, chills, pain in the inguinal region) or urinary urgency should prompt drug withdrawal and dosage reevaluation.1

Male patients receiving oxandrolone may experience feminization due to gonadotrophin suppression. The feminizing effects are generally reversible with drug discontinuation. Impotence (erectile dysfunction), libido decrease, oligospermia, testicular atrophy, bladder irritation (bladder discomfort), gynecomastia, and epididymitis may occur.1

Oxandrolone has the potential for teratogenesis (possible masculinization of the fetus) and, thus, is a pregnancy category X drug.1

Periodic lipoprotein monitoring is recommended due to the possible development of hypercholesterolemia consisting of decreased high-density lipoproteins (HDL) and increased low-density lipoproteins. Alteration in the total cholesterol concentration may be minimal. The percentage decrease in HDL was 44% from one study of patients on 7.5 mg daily. There appears to be minimal to no dose relationship to the degree of HDL lowering. The nadir of HDL appears to occur in about seven days with reversal of these changes within one month of oxandrolone discontinuation. The magnitude of these changes can be significant especially for patients with preexisting cardiac disease. Periodic assessment of serum lipoprotein concentrations is recommended especially for patients with cardiovascular disease.1

Anabolic steroids may cause suppression of clotting factors II, V, VII, and X. A clotting factor deficiency or coagulopathy may occur with oxandrolone.1

Periodic measurement of hemoglobin and hematocrit is warranted in patients receiving high doses of oxandrolone due to the potential development of polycythemia.1

Storage

Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain.

  • 1. a. b. c. d. e. f. g. h. i. j. k. l. m. n. o. Oxandrin (oxandrolone) tablet package insert. East Brunswick, NJ: Savient Pharmaceuticals, Inc.; 2006 Jan.
  • 2. a. b. c. Kochenour NK. Lactation suppression. Clin Obstet Gynecol. 1980;23:1045-1059.
  • 3. Health Care Financing Administration. Interpretive Guidelines for Long-term Care Facilities. Title 42 CFR 483.25(l) F329: Unnecessary Drugs. Revised 2015.

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