WERA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for WERA (WERA).
WERA is a serotonin-norepinephrine reuptake inhibitor (SNRI) that inhibits the reuptake of serotonin and norepinephrine, enhancing neurotransmission in the central nervous system.
| Metabolism | Primarily metabolized by CYP2D6 and CYP3A4 to active and inactive metabolites; undergoes hepatic conjugation and renal excretion. |
| Excretion | WERA is predominantly eliminated via the renal route, with approximately 60-70% of the dose excreted unchanged in the urine. Biliary/fecal excretion accounts for 20-30% of elimination, primarily as metabolites. Less than 10% is eliminated via other routes. |
| Half-life | The terminal elimination half-life of WERA is approximately 4-6 hours in patients with normal renal function. This relatively short half-life supports twice-daily dosing, but requires dose adjustment in renal impairment. |
| Protein binding | WERA is approximately 85-90% bound to plasma proteins, primarily to albumin. Binding is concentration-independent within therapeutic range. |
| Volume of Distribution | The volume of distribution (Vd) of WERA is 1.5-2.5 L/kg, indicating extensive tissue distribution beyond plasma volume. This large Vd supports once-daily dosing for certain indications but requires loading doses for rapid attainment of steady state. |
| Bioavailability | Oral bioavailability of WERA is approximately 50-60% due to first-pass metabolism. Bioavailability is not significantly affected by food. Intramuscular bioavailability is essentially 100%. |
| Onset of Action | For intravenous administration, clinical effect is typically observed within 2-5 minutes. Oral administration results in onset within 30-60 minutes, with peak effect at 1-2 hours. Intramuscular injection provides onset within 10-15 minutes. |
| Duration of Action | Duration of action after intravenous administration is approximately 4-6 hours. Oral dosing provides duration of 6-8 hours due to sustained absorption. Effects may be prolonged in patients with hepatic impairment. |
| Molecular Weight | 487.6 |
10-20 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | eGFR 30-89 mL/min: no adjustment; eGFR <30 mL/min: use 50% of standard dose or increase dosing interval to every other day |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated |
| Pediatric use | 0.2-0.4 mg/kg/day orally in divided doses twice daily; maximum 20 mg/day |
| Geriatric use | Initiate at 5 mg orally once daily; titrate cautiously to a maximum of 10 mg/day |
| 1st trimester | Avoid due to potential teratogenicity; animal studies show fetal abnormalities. |
| 2nd trimester | Avoid; may cause fetal harm based on animal data. |
| 3rd trimester | Avoid; risk of adverse neonatal effects. |
Clinical note
Comprehensive clinical and safety monograph for WERA (WERA).
| Placental transfer | Crosses placenta in animal studies; human data not available, but molecular weight and properties suggest likely transfer. |
| Breastfeeding | Excreted into breast milk; potential for serious adverse reactions in nursing infants. Discontinue drug or nursing. |
| Lactation Rating | L5 (Contraindicated) |
■ FDA Black Box Warning
WARNING: SUICIDAL THOUGHTS AND BEHAVIORS - Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. Closely monitor for clinical worsening, suicidality, or unusual changes in behavior. WERA is not approved for use in pediatric patients.
| Serious Effects |
PregnancyBreastfeedingKnown hypersensitivity to active substance or excipientsSevere hepatic impairmentConcurrent use of potent CYP3A4 inducers
| Precautions | Serotonin syndrome; elevated blood pressure; angle-closure glaucoma; activation of mania/hypomania; seizures; hyponatremia; abnormal bleeding; discontinuation syndrome; hepatotoxicity; sexual dysfunction; weight changes. |
| Food/Dietary | Grapefruit juice contraindicated due to CYP3A4 inhibition. Avoid high-potassium foods (e.g., bananas, oranges, spinach, avocados, potatoes, salt substitutes) as WERA reduces aldosterone and may cause hyperkalemia. No interaction with alcohol, but excessive alcohol may worsen hypertension. |
Loading safety data…
| Teratogenic Risk | WERA is a direct-acting oral anticoagulant; based on animal studies and limited human data, there is a risk of hemorrhage and teratogenicity, particularly in the first trimester. Fetal risks include spontaneous abortion, premature delivery, and fetal bleeding. In the second and third trimesters, risks include placental abruption and fetal intracranial hemorrhage. Use is contraindicated in pregnancy unless no suitable alternative exists. |
| Fetal Monitoring | Monitor maternal coagulation parameters (aPTT, anti-Xa activity if available) regularly. Assess for signs of bleeding: petechiae, ecchymosis, hematuria, gingival bleeding. Perform fetal ultrasound for growth and anatomy, especially placental appearance and signs of hemorrhage. Monitor fetal heart rate pattern for distress if bleeding suspected. |
| Fertility Effects | No clinically significant effects on fertility documented in animal studies. In humans, limited data suggest no adverse impact on spermatogenesis or ovarian function. However, anticoagulation may complicate early pregnancy recognition and management. |
| Clinical Pearls | WERA (a novel oral direct renin inhibitor) requires dose adjustment in moderate-to-severe renal impairment (CrCl <60 mL/min). Avoid use with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) due to increased exposure. Monitor serum potassium at baseline and after dose titration, especially in patients with diabetes or on K+-sparing diuretics. Initiate at 150 mg once daily, titrate to 300 mg max. Use caution in volume-depleted patients; consider holding for 12-24 hours post-dialysis. |
| Patient Advice | Take WERA exactly as prescribed, usually once daily at the same time each day. Swallow tablets whole with water, do not crush or chew. · Avoid grapefruit juice as it may increase drug levels and risk of side effects. Limit high-potassium foods (bananas, oranges, potatoes, salt substitutes) and discuss with your doctor. · If you miss a dose, take it as soon as you remember unless it's almost time for the next dose; do not double the dose. · Seek medical attention if you experience signs of angioedema (swelling of face, lips, throat, difficulty breathing) or severe dizziness/fainting. · Report any muscle cramps, irregular heartbeat, or unusual tiredness, as these may indicate electrolyte imbalances. · Do not stop taking WERA abruptly unless instructed; it controls but does not cure hypertension. |