|Composition||Telmisartan 80/ 40 mg+ Chlorthalidone 12.5 mg tablets|
|Mechanism of Action||
Telmisartan is a nonpeptide AT1 angiotensin II receptor antagonist. It exerts antihypertensive activity by preventing angiotensin II from binding to AT1 receptors thus inhibiting the vasoconstricting and aldosterone-secreting effects of angiotensin II.
Chlortalidone is an oral, long acting antihypertensive/diuretic. It is a monosulfamyl diuretic that acts by enhancing the excretion of sodium and chloride ions, and water by interfering with the transport of sodium ions across the renal tubular epithelium. Their primary site of action appears to be at the cortical diluting segment in the nephron of the loop of Henle.
Onset: 1-2 hr.
Duration: Up to 24 hr.
Absorption: Rapidly absorbed from the GI tract. Food may slightly decrease the bioavailability. Absolute bioavailability: Dose-dependent (approx 42% after 40-mg dose; 58% after 160-mg dose). Time to peak plasma concentration: Approx 0.5-1 hr.
Distribution: Volume of distribution: 500 L. Plasma protein binding: >99%. Metabolism: Undergoes conjugation w/ glucuronic acid to form inactive metabolites.
Excretion: Via faeces (97%, as unchanged drug). Terminal elimination half-life: Approx 24 hr.
Chlortalidone : Onset: 2 hr.
Duration: 48-72 hr.
Absorption: Erratic absorption from the GI tract (oral).
Distribution: Widely distributed, enters breast milk, crosses the placenta and blood-brain barrier. Volume of distribution: 3.2-5.6 L/kg. Plasma protein binding: Approx 12%.
Distribution: Binds to red blood cells; crosses the placenta and enters breast milk. Protein-binding: Weak.
Excretion: Urine (as unchanged drug); 40-60 hr (elimination half-life)..
TELMISARTAN Dizziness, fatigue, headache, sinusitis, upper resp tract infection, pharyngitis, UTI, back pain, myalgia, diarrhoea, abdominal pain, dyspepsia, nausea.
Potentially Fatal: Intermittent claudication and skin ulcer. Chlorthalidone : Dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, seizures, oliguria, hypotension, fatigue, muscle cramps and GI disturbances, nausea, vomiting, constipation, diarrhoea, anorexia. Diabetes and gout may be precipitated. Impotence. Raised blood levels of glucose, urates, lipids and calcium. Reduced levels of K and magnesium. Raised CPK levels.
Potentially Fatal: Rare. Severe hyponatraemia and idiosyncratic hypersensitivity.
TELMISARTAN : Volume- or salt-depleted patients including patients on prolonged diuretic therapy. Patients w/ renal artery stenosis, aortic or mitral stenosis, obstructive biliary disease. Renal and mild to moderate hepatic impairment. Lactation. Monitoring Parameters Monitor BP, electrolytes and serum creatinine levels.
Chlorthalidone : Existing fluid and electrolyte disturbances, hepatic cirrhosis, severe heart failure, hyperuricaemia, mild to moderate renal impairment. Elderly. Monitor fluid and electrolyte balance. Kidney or liver disease; diabetes; gout; hyperlipidaemia and ventricular extra systoles.
TELMISARTAN : HTN Initial: 40 mg once daily, may be adjusted to 20-80 mg once daily. CV risk reduction 80 mg once daily.
Chlorthalidone : HTN 25 mg/day, up to 50 mg/day.