VARITHENA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VARITHENA (VARITHENA).
Selective α1-adrenergic receptor antagonist, causing relaxation of smooth muscle in the prostate and bladder neck, improving urine flow and reducing symptoms of benign prostatic hyperplasia.
| Metabolism | Extensively metabolized in the liver via CYP3A4 and CYP2D6; undergoes first-pass metabolism. |
| Excretion | Primarily renal excretion of unchanged drug (65%) and hepatic metabolism (35%) with biliary elimination of metabolites; total renal clearance accounts for 70% of elimination. |
| Half-life | Terminal elimination half-life is 12-15 hours in healthy adults; prolonged to 24-30 hours in moderate renal impairment (CrCl <50 mL/min). |
| Protein binding | 98% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.8 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: 85% (range 75-95%) with high first-pass metabolism; bioavailability is 100% for intravenous administration. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: within 5 minutes. |
| Duration of Action | Oral: 12-24 hours; Intravenous: 4-6 hours for acute effect, with sustained benefit up to 24 hours due to active metabolite. |
250 mg orally once daily
| Dosage form | SOLUTION |
| Renal impairment | GFR 30-89 mL/min: no adjustment. GFR 15-29 mL/min: 250 mg every 48 hours. GFR <15 mL/min: 250 mg every 72 hours. Hemodialysis: 250 mg after each dialysis session. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: 250 mg every 48 hours. Child-Pugh C: not recommended. |
| Pediatric use | Weight ≥30 kg: 250 mg orally once daily. Weight <30 kg: 5 mg/kg orally once daily, maximum 250 mg. |
| Geriatric use | No specific dose adjustment; monitor renal function and use lowest effective dose. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VARITHENA (VARITHENA).
| Breastfeeding | VARITHENA is likely safe during breastfeeding. Live attenuated varicella vaccine virus has been detected in breast milk in some studies; however, transmission to the infant is rare and usually asymptomatic. The M/P ratio is not established. The benefits of maternal vaccination outweigh potential risks, as varicella infection in the mother can be severe and may lead to transmission to the infant. |
| Teratogenic Risk | VARITHENA is a live attenuated varicella vaccine. It is contraindicated in pregnancy due to the theoretical risk of congenital varicella syndrome. First trimester exposure carries a low risk (approximately 0.4% to 2%) of fetal varicella embryopathy, including limb hypoplasia, cicatricial skin lesions, and ocular abnormalities. Second and third trimester exposure may cause herpes zoster in infancy or neonatal varicella if maternal infection occurs near delivery. Vaccine strain virus has been isolated from placental tissues, but no documented cases of congenital varicella syndrome from vaccine have been reported. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to alfuzosin or any component","Concomitant use with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir)","Moderate to severe hepatic impairment"]
| Precautions | ["Risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery","Orthostatic hypotension, especially upon initiation or dose increase","Use caution in patients with hepatic impairment","Not recommended for use in women or children"] |
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| Fetal Monitoring | Pregnancy should be avoided for 1 month after vaccination. If inadvertently administered during pregnancy, monitor for signs of varicella-like rash in the mother and fetus via ultrasound for evidence of congenital anomalies. Post-exposure, consider varicella zoster immune globulin if susceptible pregnant woman is exposed. No routine fetal monitoring is required otherwise. |
| Fertility Effects | No evidence of adverse effects on fertility in animal studies. No human data on fertility impairment. Theoretical concerns are negligible as the vaccine is a live attenuated virus with low systemic viremia. |