Nebido (Testosterone Undecanoate)

• Nebido is used in androgen‑related disorders to restore physiological testosterone levels.
• Male hypogonadism: improves symptoms such as low libido, fatigue and loss of muscle mass.
• Testosterone deficiency: normalises serum testosterone and supports anabolic processes.
• Delayed puberty in males: promotes development of secondary sexual characteristics.

• Testosterone undecanoate is hydrolysed after intramuscular injection to release testosterone, which binds to intracellular androgen receptors. The hormone‑receptor complex translocates to the nucleus, modulating gene transcription that drives protein synthesis, erythropoiesis, and development of male sexual characteristics, thereby restoring normal hormonal balance.

Nebido may cause a range of adverse reactions, some of which are more frequent than others.

Common Side Effects

• Acne or oily skin.
• Increased red blood cell count (erythrocytosis).
• Fluid retention or peripheral edema.
• Elevated prostate‑specific antigen (PSA) levels.
• Mood swings or irritability.
• Decreased sperm production.

Serious or Rare Side Effects

• Thromboembolic events such as deep‑vein thrombosis.
• Cardiovascular complications including myocardial infarction.
• Severe allergic reactions (anaphylaxis, angioedema).
• Progression of prostate cancer.
• Significant liver enzyme elevation.
• Sleep‑apnoea worsening.

• Before initiating Nebido therapy, several safety considerations should be addressed.
• Monitor hematocrit: perform regular blood counts to detect erythrocytosis.
• Assess cardiovascular risk: evaluate history of heart disease or stroke.
• Screen for prostate disease: conduct PSA testing and digital rectal exam.
• Avoid use in known hypersensitivity: discontinue if allergic reaction occurs.
• Use caution in hepatic impairment: monitor liver function tests.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Nebido can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Warfarin: may increase anticoagulant effect and bleeding risk.
• Insulin or oral hypoglycemics: can affect glucose control, requiring dose adjustments.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): may raise testosterone levels.

Moderate Interactions (Monitor Closely)

• Antihypertensives: testosterone may reduce their blood‑pressure‑lowering effect.
• Glucocorticoids: combined use can exacerbate fluid retention.
• Estrogen therapy: may antagonise the intended androgenic effects.