Male hypogonadism
Adult: 10-50 mg daily. Dosage is adjusted and individualised depending on the patient's response and tolerability.
Oral
Metastatic breast carcinoma in postmenopausal women
Adult: 50-200 mg daily.
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Indications and Dosage
                                             
                                            
Oral 
                                        Male hypogonadism Adult: 10-50 mg daily. Dosage is adjusted and individualised depending on the patient's response and tolerability. Oral Metastatic breast carcinoma in postmenopausal women Adult: 50-200 mg daily. 
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Contraindications
                                             
                                            
Men with breast cancer or those with known or suspected prostate cancer. Pregnancy and women of childbearing potential.
                                             
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Special Precautions
                                             
                                            
Patient with breast cancer; diseases that may be exacerbated by fluid retention (e.g. cardiac impairment); risk factors for sleep apnoea (e.g. obesity, chronic lung disease). Not recommended for use in patients with thrombophilia, severe lower respiratory tract symptoms. Hepatic and renal impairment. Lactation.
                                             
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Adverse Reactions
                                             
                                            
Significant: Peliosis hepatitis, hepatic neoplasms, hepatocellular carcinoma, cholestatic hepatitis, jaundice, CV events (e.g. MI); oligospermia, polycythaemia, priapism; venous thromboembolic events (e.g. DVT, pulmonary embolism); worsened benign prostatic hyperplasia, gynaecomastia; urethral obstruction; hypercalcaemia, fluid retention, oedema with or without CHF; increased risk of prostate cancer; exacerbated sleep apnoea (male patients); virilisation (e.g. deepening of voice, menstrual irregularities, clitromegaly, hirsutism, acne) in females. 
                                        Blood and lymphatic system disorders: Clotting factors suppression. Gastrointestinal disorders: Nausea. Investigations: Increased serum cholesterol. Metabolism and nutrition disorders: Retention of Ca, K, Na, NaCl. Nervous system disorders: Headache, paraesthesia. Psychiatric disorders: Anxiety, depression. Reproductive system and breast disorders: Increased or decreased libido. Skin and subcutaneous tissue disorders: Acne vulgaris, androgenetic alopecia (male).  | 
                                
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Monitoring Parameters
                                             
                                            
Monitor LFTs, lipid panel, Hb, and haematocrit (at 3-6 months and annually); urine, serum Ca, serum glucose. Monitor for signs and symptoms of CV and venous thromboembolic events, liver toxicity, and virilisation in females.
                                             
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Drug Interactions
                                             
                                            
May enhance the anticoagulant effect of vitamin K antagonists (e.g. warfarin). May increase serum levels of oxyphenbutazone. May enhance the hypoglycaemic effect of blood glucose lowering agents.
                                             
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Lab Interference
                                             
                                            
May reduce thyroxine-binding globulin, causing reduced total T4 serum levels and enhanced reuptake of T3 and T4.
                                             
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Action
                                             
                                            
Description:  
                                        Mechanism of Action: Methyltestosterone, a synthetic androgenic anabolic steroid, is used primarily for the substitution of diminished or absent endogenous testicular hormone. Pharmacokinetics: Distribution: Plasma protein binding: 98% to sex hormone-binding globulin. Metabolism: Metabolised in the liver. Excretion: Via urine (approx 90%); faeces (approx 6%). Elimination half-life: 10-100 minutes (may vary).  | 
                                
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Chemical Structure
                                             
                                            ![]() Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 6010, Methyltestosterone. https://pubchem.ncbi.nlm.nih.gov/compound/Methyltestosterone. Accessed Nov. 25, 2024.  | 
                                
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Storage
                                             
                                            
Store between 15-30°C. Protect from light, moisture, and heat.
                                             
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ATC Classification
                                             
                                            
G03BA02 - methyltestosterone ; Belongs to the class of 3-oxoandrosten (4) derivative androgens used in androgenic hormone preparations.  
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References
                                             
                                            
Anon. Methyltestosterone. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 10/10/2024.  Brayfield A, Cadart C (eds). Methyltestosterone. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/10/2024.  Methyltestosterone Capsule (Novitium Pharma LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 10/10/2024.  Methyltestosterone. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 10/10/2024.  
                                             
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