REZIPRES
Clinical safety rating
cautionComprehensive clinical and safety monograph for REZIPRES (REZIPRES).
REZIPRES is a combination of irbesartan, an angiotensin II receptor blocker (ARB), and amlodipine, a calcium channel blocker. Irbesartan inhibits the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the AT1 receptor. Amlodipine inhibits the influx of calcium ions into vascular smooth muscle and cardiac muscle, leading to vasodilation and reduced peripheral vascular resistance.
| Metabolism | Irbesartan is metabolized via glucuronidation and oxidation by CYP2C9. Amlodipine is extensively metabolized in the liver via CYP3A4. |
| Excretion | Primarily hepatic metabolism via CYP3A4 and CYP2C9, with 60% eliminated in feces and 25% in urine as metabolites; <5% excreted unchanged in urine. |
| Half-life | Terminal elimination half-life is approximately 40-50 hours, supporting once-daily dosing; steady-state achieved in 7-10 days. |
| Protein binding | >99% bound, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 30-50 L (0.43-0.71 L/kg for a 70 kg adult), indicating extensive extravascular distribution. |
| Bioavailability | Oral bioavailability 50-60% due to first-pass metabolism; food decreases absorption by 20%. |
| Onset of Action | Oral: 2-4 hours after first dose for detectable blood pressure reduction; maximal effect in 2-4 weeks. |
| Duration of Action | 24 hours with once-daily dosing; blood pressure reduction sustained over 24 hours without loss at trough. |
| Molecular Weight | 500.6 |
Adults: 2 mg orally twice daily.
| Dosage form | SOLUTION |
| Renal impairment | GFR ≥30 mL/min: No adjustment. GFR <30 mL/min: 1 mg orally twice daily. ESRD (dialysis): 1 mg orally once daily. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: 1 mg orally twice daily. Child-Pugh C: 0.5 mg orally twice daily. |
| Pediatric use | Children <12 years: Not established. Children ≥12 years: Same as adult dosing. |
| Geriatric use | No specific dose adjustment; monitor renal function and use lowest effective dose. |
| 1st trimester | Limited data; avoid due to potential teratogenic effects in animal studies. |
| 2nd trimester | Use only if benefit outweighs risk; monitor fetal growth. |
| 3rd trimester | May cause neonatal adverse effects; avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for REZIPRES (REZIPRES).
| Placental transfer | Crosses placenta in animal models; human data lacking. |
| Breastfeeding | Not recommended due to potential excretion in milk and risk of infant toxicity. |
| Lactation Rating | L5 (Contraindicated) |
| Teratogenic Risk | Pregnancy Category X. First trimester: high risk of major congenital malformations including craniofacial, cardiac, and neural tube defects based on animal studies and human case reports. Second and third trimesters: fetal growth restriction, oligohydramnios, and neonatal renal failure. Contraindicated in pregnancy. |
| Fetal Monitoring | Pregnancy test before initiation and monthly thereafter; fetal ultrasound for anomalies and amniotic fluid volume assessment; maternal renal and hepatic function tests every 4 weeks; consult maternal-fetal medicine specialist if pregnancy occurs. |
| Fertility Effects | May impair female fertility due to hormonal disruption observed in animal studies. Reversible upon discontinuation. Male fertility effects include reduced spermatogenesis and sperm motility. |
■ FDA Black Box Warning
WARNING: FETAL TOXICITY. Drugs acting directly on the renin-angiotensin system can cause injury and death to the developing fetus. Discontinue as soon as possible once pregnancy is detected.
| Serious Effects |
Hypersensitivity to active substanceSevere hepatic impairmentPregnancy
| Precautions | Hypotension in volume- or salt-depleted patients, Increased angina or myocardial infarction with calcium channel blockers, especially in patients with severe obstructive coronary artery disease, Monitor renal function and potassium levels, Avoid use in patients with severe renal impairment (GFR <30 mL/min) |
| Food/Dietary | Avoid high-potassium foods (e.g., bananas, oranges, potatoes, spinach, salt substitutes) due to risk of hyperkalemia from perindopril. Grapefruit and grapefruit juice should be limited or avoided as they can increase amlodipine levels and risk of side effects. Consume a heart-healthy diet low in sodium and saturated fats. |
| Clinical Pearls | Rezipres (fixed-dose combination of perindopril and amlodipine) is indicated for hypertension. Monitor serum potassium and renal function due to perindopril's ACE inhibitor effect. Amlodipine may cause peripheral edema, especially in elderly or those on high doses; consider adding a diuretic if edema persists. Avoid use with aliskiren in patients with diabetes or renal impairment (GFR <60 mL/min). Titrate dose gradually to minimize hypotensive effects. |
| Patient Advice | Take this medication exactly as prescribed, usually once daily. · Avoid salt substitutes containing potassium unless approved by your doctor. · Report any signs of angioedema (swelling of face, lips, throat) immediately. · Do not stop taking this medication suddenly; it may cause a rapid increase in blood pressure. · If you miss a dose, take it as soon as you remember unless it is almost time for the next dose; do not double the dose. · This medication may cause dizziness; avoid driving or operating machinery until you know how it affects you. · Monitor your blood pressure regularly and keep follow-up appointments. · Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. |
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