|Composition||Benidipine Hydrochloride 4 mg + Chlorthalidone 12.5 /6.25 mg tablets|
|Mechanism of Action||
Benidipine: The vasorelaxant effect of benidipine is due to its affinity towards dihydropyridine binding sites in calcium channels. Binding of benidipine with calcium channels inhibits calcium current. The onset of action is slow, which results in minimal tachycardia or palpitation
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.
Benidipine: Rapid absorption. Cmax within 2 h. Highest level in the liver and also distribution in the kidneys, plasma, and other tissues. No tissue showed a particularly high accumulation of the drug following repeated oral administrations. Protein binding 98% The percentage urinary excretion of benidipine following an oral dose is about 36%
Chlortalidone: Onset: 2 hr.
Duration: 48-72 hr.
Absorption: Erratic absorption from the GI tract (oral).
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).
Benidipine: Palpitation, facial flushing, hot flushes, chest pressure sensation, headache, dizziness, sleepiness, constipation, nausea, abdominal discomfort, oedema, malaise, tinnitus, redness and warm feeling in the fingers, shoulder stiffness, increased frequency of micturition. Hypersensitive reactions e.g. Rash and itching. Elevation of SGOT, SGPT, alkaline phosphatase, total bilirubin, creatinine and uric acid.
Chlortalidone : 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.
Benidipine Elderly. In case of dizziness or light-headedness, advise patients against handling of heavy machines or working at elevated spots. Reduce dosage gradually while withdrawing drug. Liver function tests.
Chlortalidone: 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.
Benidipine: Adult: PO HTN 2-4 mg once daily, up to 8 mg once daily if needed. Angina pectoris 4 mg twice daily.
Chlortalidone: Adult: PO HTN 25 mg/day, up to 50 mg/day. Oedema Initial: 25-50 mg/day up to 100-200 mg/day in severe cases. Maintenance: 25-50 mg/day or on alternate days. Diabetes insipidus Initial: 100 mg twice daily. Maintenance: 50 mg/day.