OLMESARTAN MEDOXOMIL
Clinical safety rating: avoid
NSAIDs may diminish the antihypertensive effect Lithium levels may be increased Use in pregnancy can cause injury and death to the developing fetus.
Olmesartan medoxomil is a prodrug that is hydrolyzed to olmesartan, a selective angiotensin II receptor type 1 (AT1) antagonist. It blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II, leading to decreased peripheral vascular resistance and reduced blood pressure.
| Metabolism | Olmesartan medoxomil is completely hydrolyzed to olmesartan during absorption by esterases in the gastrointestinal tract. Olmesartan is not metabolized by the cytochrome P450 system and is excreted unchanged in the urine (35-50%) and feces (50-65%). |
| Excretion | Renal: 35-50% as unchanged drug; biliary/fecal: 50-65% via bile into feces, primarily as parent drug. |
| Half-life | Terminal elimination half-life: 10-15 hours; reaches steady-state after 3-5 days; clinically allows once-daily dosing. |
| Protein binding | >99% bound, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd: 17-24 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: 26% (absolute bioavailability due to extensive first-pass metabolism). |
| Onset of Action | Oral: 1-2 hours for peak plasma concentration; antihypertensive effect begins within 1 week, maximal at 2-4 weeks. |
| Duration of Action | 24 hours with once-daily dosing; blood pressure reduction sustained over 24-hour dosing interval. |
| Molecular Weight | 558.59 |
20 mg orally once daily, titrate as needed to 40 mg once daily; maximum 40 mg daily.
| Dosage form | TABLET |
| Renal impairment | No adjustment required for GFR ≥20 mL/min; contraindicated if GFR <20 mL/min. |
| Liver impairment | No dosage adjustment necessary for mild-to-moderate hepatic impairment (Child-Pugh A or B); not recommended in severe hepatic impairment (Child-Pugh C) due to lack of data. |
| Pediatric use | Children 1-16 years: initial dose 0.1 mg/kg (max 20 mg) orally once daily, titrate up to 0.6 mg/kg (max 40 mg) once daily; weigh-based titration. |
| Geriatric use | Initiate at 10 mg once daily in elderly patients ≥75 years due to increased risk of hypotension; titrate slowly. |
| 1st trimester | Avoid; associated with fetal renal abnormalities and oligohydramnios. |
| 2nd trimester | Contraindicated; risk of fetal renal dysfunction, oligohydramnios, and skull ossification defects. |
| 3rd trimester | Contraindicated; risk of fetal renal failure, oligohydramnios, and neonatal hypotension. |
Clinical note
NSAIDs may diminish the antihypertensive effect Lithium levels may be increased Use in pregnancy can cause injury and death to the developing fetus.
| FDA category | Contraindicated |
| Placental transfer | Crosses placenta; detected in fetal circulation. |
| Breastfeeding | Not recommended; excreted into breast milk in animal studies, unknown human effects. |
■ FDA Black Box Warning
None
| Common Effects | Sleepiness Taste change Ankle swelling Headache Flushing sense of warmth in the face ears neck and trunk Dizziness Tiredness Palpitations Upset stomach Increased potassium level in blood |
| Serious Effects |
PregnancyHypersensitivity to olmesartan or any componentConcomitant use with aliskiren in patients with diabetes mellitus
| Precautions | Hypotension in volume-depleted patients, Worsening renal function, especially in patients with renal artery stenosis, Hyperkalemia, particularly in patients with renal impairment or on potassium-sparing diuretics, Fetal toxicity: potential for oligohydramnios and fetal renal dysfunction if used during pregnancy |
| Food/Dietary | No significant food interactions. However, high-potassium foods (e.g., bananas, oranges, spinach) should be consumed in moderation to avoid hyperkalemia. Grapefruit juice has no known interaction. |
Loading safety data…
| Lactation Rating | L5 |
| Teratogenic Risk | First trimester: Limited data; potential risk based on mechanism (RAAS inhibition). Second and third trimesters: Fetal toxicity including oligohydramnios, renal dysplasia, skull ossification defects, hypotension, and anuria. Avoid in second and third trimesters; use alternative if possible in first trimester. |
| Fetal Monitoring | Monitor maternal blood pressure, renal function, and serum electrolytes. Fetal ultrasound to assess amniotic fluid volume and renal function if exposed in second/third trimester. |
| Fertility Effects | No human fertility studies. In animal studies, no adverse effects on fertility observed at clinically relevant doses. |
| Clinical Pearls | Olmesartan medoxomil is a prodrug hydrolyzed to olmesartan, an angiotensin II receptor blocker (ARB). It is used for hypertension. Onset of action is 1-2 weeks, maximal effect at 4-8 weeks. Dose adjustment not required in renal impairment but caution in severe renal disease. Avoid in pregnancy (category D). Monitor renal function and electrolytes. May cause hyperkalemia, especially with NSAIDs or potassium supplements. A rare but serious adverse effect is sprue-like enteropathy, presenting with severe diarrhea and weight loss; discontinue if suspected. Combination with aliskiren is contraindicated in diabetes. |
| Patient Advice | Take exactly as prescribed, usually once daily. · Can be taken with or without food. · Do not stop taking without consulting your doctor. · Report severe, persistent diarrhea to your doctor immediately. · Avoid potassium supplements or salt substitutes containing potassium. · Stay hydrated, especially during exercise or hot weather. · If you become pregnant, stop taking and call your doctor right away. · Do not take with aliskiren if you have diabetes. |