TELMISARTAN
Clinical safety rating: avoid
Contraindicated (not allowed)
Angiotensin II receptor antagonist; selectively blocks the binding of angiotensin II to AT1 receptors, leading to vasodilation, reduced aldosterone secretion, and decreased blood pressure.
| Metabolism | Primarily metabolized by glucuronidation (via UGT1A3 and UGT2B7); minor CYP2C9 metabolism; excreted mainly in feces as unchanged drug. |
| Excretion | Primarily biliary-fecal (approximately 97% unchanged in feces); renal excretion accounts for <1% of the dose. |
| Half-life | Terminal half-life is approximately 24 hours (range 20–30 hours), supporting once-daily dosing without significant accumulation. |
| Protein binding | >99.5% bound, primarily to albumin and alpha-1 acid glycoprotein. |
| Volume of Distribution | Approximately 500 L (7 L/kg for a 70 kg adult), indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is 42–58% (mean ~50%), unaffected by food. |
| Onset of Action | Oral: antihypertensive effect begins within 3 hours, with peak effect at 4–8 hours. |
| Duration of Action | Duration of antihypertensive effect is at least 24 hours, maintaining efficacy over the dosing interval with trough-to-peak ratio >80%. |
40 mg orally once daily; range 20-80 mg/day
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min. Safety/efficacy not established in GFR <30 mL/min; use not recommended. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh C). For mild-moderate (Child-Pugh A/B): maximum dose 40 mg once daily. |
| Pediatric use | Not approved for use in pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dose adjustment required; consider lower starting dose (20 mg) due to potential greater sensitivity and decreased renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
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.
| Breastfeeding | No human data on excretion; telmisartan is highly protein-bound and likely present in milk. M/P ratio not established. Avoid breastfeeding due to potential neonatal risk. |
| Teratogenic Risk | First trimester: Potential risk based on renin-angiotensin system blockade; second and third trimesters: Oligohydramnios, fetal renal dysfunction, skull ossification defects, hypotension, anuria, renal failure, and death. Angiotensin II receptor antagonists are not recommended in pregnancy. |
■ FDA Black Box Warning
None.
| Common Effects | Hyperkalemia |
| Serious Effects |
["Hypersensitivity to telmisartan or any component","Concomitant use with aliskiren in patients with diabetes mellitus or renal impairment (GFR <60 mL/min/1.73 m²)","Pregnancy (second and third trimesters)"]
| Precautions | ["Fetal toxicity: Can cause fetal harm if used during pregnancy; discontinue as soon as possible.","Avoid use with aliskiren in patients with diabetes or renal impairment (eGFR <60 mL/min).","May cause symptomatic hypotension, especially in volume-depleted patients.","Monitor renal function and potassium levels; risk of hyperkalemia.","May cause angioedema, though rare."] |
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| Fetal Monitoring |
| Monitor fetal ultrasound for amniotic fluid volume and renal function; maternal blood pressure and renal function regularly; fetal heart rate monitoring if used inadvertently in later pregnancy. |
| Fertility Effects | No human data; animal studies show no impairment of fertility. Theoretical effect on renin-angiotensin system may impact sperm function; clinical significance unknown. |