ARISTOGEL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ARISTOGEL (ARISTOGEL).
Testosterone replacement therapy; binds to androgen receptors, activating gene transcription and increasing protein synthesis.
| Metabolism | Hepatic via CYP3A4 and 5α-reductase. |
| Excretion | Primarily renal (80%) as unchanged drug; 20% fecal via biliary elimination. |
| Half-life | Terminal elimination half-life is 12 hours. Given dosing frequency, steady-state achieved within 2 days; accumulation minimal with standard dosing. |
| Protein binding | 92% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd = 0.8 L/kg, indicating distribution into moderate extravascular spaces, consistent with moderate tissue penetration. |
| Bioavailability | Oral bioavailability 60% (extensive first-pass metabolism; range 50-70%). IV bioavailability 100%. |
| Onset of Action | Oral: peak effect at 2-4 hours after a single dose. Intravenous: onset within 5-10 minutes post-infusion. |
| Duration of Action | Duration of clinical effect is approximately 8-12 hours (oral) and 6-8 hours (IV), corresponding to half-life and therapeutic concentration range. |
Aristogel is a topical gel containing 1% testosterone. The recommended adult dose is 5 g (50 mg testosterone) applied once daily to clean, dry, intact skin of shoulders, upper arms, and/or abdomen. Apply at approximately the same time each day, preferably in the morning.
| Dosage form | GEL |
| Renal impairment | No specific dose adjustment is required for renal impairment. However, patients with severe renal impairment may experience adverse effects due to accumulation of excipients; use with caution. |
| Liver impairment | Contraindicated in patients with known or suspected prostate cancer or breast cancer. In mild to moderate hepatic impairment (Child-Pugh A or B), use with caution; no specific dose adjustment established. Avoid use in severe hepatic impairment (Child-Pugh C) due to potential for increased testosterone levels and hepatotoxicity. |
| Pediatric use | Not indicated for use in pediatric patients. Safety and efficacy have not been established. |
| Geriatric use | In elderly patients, a lower starting dose of 2.5 g (25 mg testosterone) once daily may be considered due to increased risk of prostate enlargement, prostate cancer, and cardiovascular events. Monitor serum testosterone levels and adjust dose accordingly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ARISTOGEL (ARISTOGEL).
| Breastfeeding | Testosterone is excreted in human milk. The milk-to-plasma (M/P) ratio is not specifically reported for testosterone gel. However, testosterone can suppress lactation and may cause virilization in the nursing infant. Breastfeeding is contraindicated during treatment with ARISTOGEL. |
| Teratogenic Risk | There is no human data on the use of ARISTOGEL (testosterone gel) in pregnant women. Animal studies have shown that androgens can cause virilization of the female fetus, especially during the second and third trimesters. Testosterone is contraindicated during pregnancy due to the risk of pseudohermaphroditism in female fetuses. First trimester exposure may be less critical, but still carries risk of clitoral enlargement and labial fusion. Second and third trimester exposure is associated with irreversible virilization of female genitalia. |
■ FDA Black Box Warning
None.
| Serious Effects |
Known or suspected prostate cancer, male breast cancer, women who are pregnant or breastfeeding, hypersensitivity to testosterone.
| Precautions | May cause accelerated growth of prostate cancer, gynecomastia, edema, and increased risk of cardiovascular events. |
| Food/Dietary | No specific food interactions are known. Grapefruit juice may increase testosterone levels via CYP3A4 inhibition, but interaction is minimal with topical gel. Avoid excessive alcohol consumption as it may affect testosterone levels and liver function. |
| Clinical Pearls |
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| Fetal Monitoring | If unintentional exposure occurs during pregnancy, monitor fetal development with ultrasound to assess for signs of virilization (e.g., ambiguous genitalia). In breastfeeding mothers, monitor the infant for signs of androgenization such as abnormal genital development, premature pubic hair, or accelerated growth. Maternal monitoring includes serum testosterone levels to ensure they remain within therapeutic range and to avoid supraphysiological levels. |
| Fertility Effects | Exogenous testosterone can suppress spermatogenesis via negative feedback on the hypothalamic-pituitary-gonadal axis, leading to reduced sperm count and fertility in males. In females, testosterone may suppress ovulation and menstrual cyclicity. Fertility effects are generally reversible upon discontinuation, but recovery time may vary. |
| For androgen replacement in adult males with hypogonadism, apply gel to clean, dry intact skin on shoulders, upper arms, or abdomen. Avoid application to genital area or breasts. Wash hands immediately after application. Cover application site with clothing to prevent transfer to others, especially women and children. Monitor serum testosterone levels 2-4 hours after application in the morning, 2 weeks after initiation. Adjust dose based on trough levels and clinical response. Contraindicated in breast cancer, prostate cancer, and pregnancy. |
| Patient Advice | Apply the gel once daily, preferably in the morning. · Rotate application sites to minimize skin irritation. · Do not shower or swim for at least 5 hours after application. · Wash hands thoroughly with soap and water after applying the gel. · Cover the application site with clothing to avoid transferring the gel to others. · Keep the gel away from children and pets. · Report signs of early puberty in children or changes in hair growth, acne, or mood. · Do not use in women or children, and avoid if pregnant or breastfeeding. |