Short answer: Telmisartan has a half-life of about 24 hours. Levels peak 0.5 to 1 hour after a dose. People vary, so treat these as estimates.
Telmisartan is an angiotensin II receptor blocker (ARB). It stops the hormone angiotensin II from binding to its AT1 receptor, which relaxes blood vessels and lowers aldosterone release, so blood pressure falls. It was first sold as Micardis (Boehringer Ingelheim); today it is sold as generic telmisartan tablets, and Micardis HCT combines it with hydrochlorothiazide.
Also known as: Micardis.
Telmisartan tablets come as 20 mg, 40 mg and 80 mg. Drugs@FDA lists the brand Micardis tablets as discontinued, not for safety or effectiveness reasons; generic tablets remain.
The current telmisartan label approves it to treat high blood pressure. Label dosing: the usual start is 40 mg once a day, and the range is 40 to 80 mg once a day, with or without food. Most of the effect shows within 2 weeks and the full effect by about 4 weeks. If more lowering is needed beyond 80 mg, the label says a diuretic may be added. No starting-dose change is needed for older adults or for kidney impairment, including dialysis; with liver impairment or blocked bile flow, it is started low and raised slowly.
The label has a boxed warning: drugs that act on the renin-angiotensin system can injure or kill a developing baby, so telmisartan is stopped as soon as pregnancy is found. It is not used with a known allergy to telmisartan, or with aliskiren in people with diabetes. Other warnings are low blood pressure at the start in people low on fluid or salt, high potassium, and kidney changes. In the ONTARGET trial (25,620 people), telmisartan plus ramipril gave no added benefit over either drug alone and caused more low blood pressure, high potassium and kidney problems. In the label's placebo-controlled trials, side effects included upper respiratory infection (7% vs 6% on placebo), back pain (3% vs 1%), sinusitis (3% vs 2%) and diarrhea (3% vs 2%). Telmisartan raised digoxin peak levels by a median 49%.
The telmisartan label gives an elimination half-life of about 24 hours and peak levels 0.5 to 1 hour after a dose. Absorption depends on dose: 42% at 40 mg and 58% at 160 mg. Food lowers it slightly. More than 97% leaves unchanged in the stool through bile, and very little in urine. Levels build up 1.5 to 2 times with once-daily dosing.
Numbers shown are taken from the source above. Half-life varies from person to person.
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