AndroGel
AndroGel
Generic Name
AndroGel
Mechanism
- Testosterone Replacement
- *Transdermal delivery* increases serum testosterone via penetration through epidermal and dermal layers.
- Endocrine Receptor Binding: Once absorbed, testosterone binds to intracellular androgen receptors in target tissues, initiating gene transcription that restores male secondary sexual characteristics and improves energy, mood, and muscle function.
- Feedback Regulation
- Restored T levels suppress gonadotropin‑releasing hormone (GnRH), lowering luteinizing hormone (LH) and follicle‑stimulating hormone (FSH), effectively shutting down endogenous testicular steroidogenesis.
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Pharmacokinetics
| Parameter | Details |
| Absorption | 70‑80% absorbed dermally; peak serum T at ~6–12 h. |
| Distribution | Protein‑bound mainly to albumin (≈90 %); free fraction (≈10 %) is biologically active. |
| Metabolism | Hepatic via 5α‑reductase and CYP3A4; conjugation to testosterone glucuronide. |
| Elimination | Renal excretion of metabolites; half‑life ≈ 4 h (steady‑state when dosing daily). |
| Steady‑State | Achieved after ≈1 week of consistent daily dosing. |
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Indications
- Male Hypogonadism (primary or secondary) refractory to other therapies.
- Androgen Deficiency in Adults
- Treatment of Gender Dysphoria (male to female) when combined with other anti‑androgens.
- Adjunct for MDMA‑reversal therapy in research settings (off‑label).
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Contraindications
| Category | Avoid if |
| Contraindicated |
• History of breast or prostate cancer, or suspicion of hormone‑sensitive tumor.
• Severe hyperandrogenic states (e.g., polycystic ovary syndrome).
• Active liver disease; hepatotoxic drugs (e.g., rifampin, fluconazole). |
| Warnings |
• Cardiovascular – monitor for heart failure, hypertension.
• Prostate – potential for benign prostatic hyperplasia (BPH) progression.
• Pregnancy – potential teratogenicity; contraindicated in pregnancy.
• women – risk of virilization. |
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Dosing
| Regimen | Dose | Application Details |
| Initial | 5 g (≈1‑2 Tbsp) once daily | 1–2 cm × 1.5 cm area on shoulders and upper arms; allow 2–4 h to dry. |
| Maintenance | 2.5–10 g (adjust per free T) | Same site; adjust based on serum free T (2–11 ng/dL) and symptomatology. |
| Maximum | 10 g/day | Do not exceed; risk of accumulation. |
| Special Populations | *Elderly*: start 2.5 g; titrate slowly.*Renal & hepatic impairment*: monitor liver enzymes; adjust if needed.* |
Application Tips
• *Avoid cross‑contamination*: Wash hands thoroughly; keep gel away from skin of genitals, eyes, and mucosa.
• *Patch test*: Check for dermatitis before full‑dose application.
• *Storage*: Keep at room temperature; avoid freezing.
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Monitoring
| Test | Frequency | Clinical Reason |
| Serum Testosterone (total & free) | 1 month after start, then quarterly | Verify therapeutic range (200–1000 ng/dL). |
| LH/FSH | Every 6 months | Assess gonadal suppression, rule out central failure. |
| PSA | Every 6 months | Detect PSA elevation indicative of prostatic changes. |
| Complete Blood Count (CBC) | 3‑month intervals | Monitor for erythrocytosis. |
| CMP (LFTs, BUN/Cr) | Every 6 months | Monitor hepatic and renal status. |
| Blood Pressure | At each visit | Detect hypertension. |
| Imaging | As indicated | Prostate ultrasound/biopsy for suspicious PSA elevation. |
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Clinical Pearls
- Transdermal Advantage: Avoid first‑pass liver metabolism—preferable in patients on potent CYP3A4 inhibitors (e.g., itraconazole).
- Skin Contact Precautions: Eggs meals >80 μL of gel contact can transmit in *males into females*; wear gloves to mitigate risk.
- T‑Test vs. Free T: When prescribing, target free T 2–11 ng/dL; free T is a better marker of bioactivity than total T.
- Rapid Dose Escalation: Increase by 2.5 g every 2–3 weeks, not more than 5 g incremental per 2 weeks to reduce virilization risk.
- Use an Agitation‑Free Tube: Avoid consistent mechanical agitation as it increases skin absorption variability.
- Hair Growth–Responsive: In patients with terminal or sensitive axillary hair, consider covering treated sites or using an underarm deodorant to reduce follicular uptake.
- Elderly Considerations: Begin at lower 2.5–5 g; adjust based on serum T and comorbidities.
- Cross‑Use with Oral danazol: May potentiate androgenic side effects; monitor ADAs.
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• Key Takeaway: *AndroGel* offers a user‑friendly, steady‑state testosterone replacement with a favorable safety profile when used correctly. Proper dosing, careful monitoring, and thorough patient education are essential for optimal therapeutic outcomes.