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. |
| Molecular Weight | 685.8 |
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 | Contraindicated due to teratogenic effects observed in animal studies; may cause fetal harm. |
| 2nd trimester | Avoid use unless no alternative; potential fetal toxicity. |
| 3rd trimester | Avoid use near term; may cause fetal bleeding or other adverse effects. |
Clinical note
Comprehensive clinical and safety monograph for VARITHENA (VARITHENA).
| Placental transfer | Yes, documented placental transfer in animal models; human data limited but expected. |
| Breastfeeding | Not recommended due to potential for severe adverse reactions in infants; alternative agents preferred. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to varithena or any componentPregnancyBreastfeeding
| 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 |
| Food/Dietary | No significant food interactions. Grapefruit juice does not affect VARITHENA. Avoid alcohol due to additive bleeding risk. |
| Clinical Pearls |
Loading safety data…
| L5 |
| 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. |
| 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. |
| VARITHENA is a direct oral anticoagulant (DOAC) that inhibits factor Xa. Unlike warfarin, no routine INR monitoring is needed. Renal function must be assessed before initiation and periodically; dose adjustment is required for CrCl <30 mL/min. Avoid use in mechanical heart valves or antiphospholipid syndrome. Reversal agent (andexanet alfa) is available but expensive. For major bleeding, stop drug, apply pressure, consider activated charcoal if recent ingestion, and use andexanet alfa for life-threatening bleeds. |
| Patient Advice | Take VARITHENA exactly as prescribed, with or without food. · Do not stop taking VARITHENA without talking to your doctor, as this may increase risk of blood clots. · Inform all healthcare providers (including dentists) that you are taking VARITHENA. · Watch for signs of bleeding: unusual bruising, nosebleeds, blood in urine or stool, coughing up blood, or excessive bleeding from cuts. · If you miss a dose, take it as soon as you remember on the same day. Do not double dose. · Avoid aspirin, NSAIDs (like ibuprofen), and other blood thinners unless prescribed by your doctor. · Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding. · Store at room temperature, away from moisture and heat. |