Testosterone potentiates the anticoagulant effect of warfarin, increasing bleeding risk (including intracranial).
Androgens/anabolic steroids inhibit hepatic synthesis of clotting factors and potentiate coumarins (Annex 7/Prontuário: anabolic steroids; testosterone labels document warfarin dose reduction).
Frequent INR in the first weeks; bleeding signs.
Bruising, gum bleeding, haematuria, sudden headache.
Reduce the warfarin dose when starting testosterone; measure INR frequently until stabilisation.
DailyMed — Testosterone Cypionate Injection [RLD Depo-Testosterone] and Warfarin Sodium Tablet labels: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=40a332e3-9c64-4595-91c3-dfef24f3d3bb
Alcohol adds hepatotoxicity to that of testosterone (particularly oral C17-alkylated esters, with reported cholestasis).
Moderate alcohol; liver monitoring with prolonged treatment.
EMC-UK — Testogel SmPC 4.4/4.8 (hepatic); Prontuário 8 (androgens — cholestasis).
Testosterone is contraindicated in known or suspected prostate cancer — it stimulates androgen-dependent tumour growth.
Exclude prostate cancer (DRE + PSA) before starting; reassess PSA periodically during therapy.
EMC-UK (MHRA) — Testogel 16.2 mg/g gel SmPC, § 4.3: "known or suspected prostate cancer or breast carcinoma": https://www.medicines.org.uk/emc/product/8919/smpc
Testosterone is contraindicated in breast carcinoma (men) — androgens may stimulate oestrogen receptors after peripheral aromatisation.
Exclude breast carcinoma before starting androgen therapy.
EMC-UK (MHRA) — Testogel SmPC, § 4.3: "known or suspected prostate cancer or breast carcinoma": https://www.medicines.org.uk/emc/product/8919/smpc
Contraindicated in pregnancy: androgens cause virilisation (masculinisation) of the female fetus — clitoral hypertrophy and fusion of the labioscrotal folds. The Prontuário classifies testosterone as risk factor D in all trimesters ("See Androgens; masculinisation of the female fetus").
Contraindicated in all trimesters; discontinue immediately if pregnancy is confirmed.
Its use during breastfeeding should be avoided (Prontuário, Annex 2): androgens may suppress lactation and cause virilisation of the infant.
Effective contraception mandatory in female partners? — not applicable; in women of child-bearing age it is contraindicated by definition. Reduced sperm count and reversible infertility are expected effects in men.
Prontuário Terapêutico INFARMED — Annex 1: "Testosterone — See Androgens; masculinisation of the female fetus, 1st/2nd/3rd, D"; Annex 2: "Testosterone — Its use during breastfeeding should be avoided".
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Maintenance of male sexual characteristics, protein anabolism and negative feedback on the hypothalamus-pituitary-gonad axis.
Intracellular androgen receptor agonist: nuclear translocation → transcription of androgen-dependent genes (DHT amplifies the signal in 5α-reductase-rich tissues).
Deep IM: slow release from the oily depot; peak 1–2 days.
In vivo ester (cipionate) hydrolysis; hepatic and peripheral metabolism (5α-reductase → DHT; aromatase → estradiol); glucuronidation and renal excretion.
~ 8 days (IM cipionate); free testosterone ~ 10–100 min.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
