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Biomedical subjects

S Sunderrajan

Publications and source records attributed to S Sunderrajan.

5 recordsLinked to original sources

Long-term renal effects of diltiazem in essential hypertension.

Eighteen hypertensive patients underwent short-term (8 weeks) and long-term (6 months) assessment of renal function and body fluid composition following diltiazem monotherapy (240 to 480 mg/day). Diltiazem monotherapy effectively lowered blood pressure in 60% of patients at 8 weeks. In 12 of the 18 patients continued on diltiazem monotherapy for 6 months, good control of blood pressure was sustained. Glomerular filtration rate, effective renal plasma flow, filtration fraction, and renal vascular resistance were unchanged throughout the protocol period. In individuals with pretreatment glomerular filtration rates less than or equal to 80 ml/min/1.73m2, diltiazem monotherapy showed both short-term and long-term improvement in glomerular filtration rate (62%) and effective renal plasma flow (34%). Filtration fraction was unchanged, suggesting that the changes in glomerular filtration rate might be related to the attenuated intrarenal effects of angiotensin II and/or norepinephrine. No long-term effect was seen on salt and water excretion or body fluid composition.

Blood Pressure

Renal effects of diltiazem in primary hypertension.

Although the calcium channel blocker diltiazem has been shown to be an effective antihypertensive agent, its effect on renal function, salt and water excretion, and body fluid composition has not been well characterized in patients with primary hypertension. Therefore, these parameters were prospectively studied in 18 subjects with primary hypertension after placebo and 8 weeks of diltiazem monotherapy. Diltiazem monotherapy was confirmed to be an effective antihypertensive agent. Although mean arterial pressure was reduced from 121 to 108 mm Hg, diltiazem had no overall effect on glomerular filtration rate, renal plasma blood flow, salt and water excretion, or body fluid composition. Renal vascular resistance, however, was decreased. In subjects with pretreatment glomerular filtration rates of 80 ml/min/1.73 m2 or less, diltiazem therapy was associated with marked improvement in glomerular filtration rate (48%) and effective renal plasma flow (36%). Since the filtration fraction was unchanged, changes in glomerular filtration rate may have been related to the attenuated intrarenal effects of angiotensin II or norepinephrine, or both.

Benzazepines

Effects of calcium entry blockers on renin-angiotensin-aldosterone system, renal function and hemodynamics, salt and water excretion and body fluid composition.

The renal effects of the calcium entry-blocking drugs diltiazem, nifedipine, verapamil and nitrendipine are reviewed. Although nifedipine stimulates plasma renin activity on a short-term basis, none of the calcium entry blockers produces a clinically significant sustained effect on any of the components of the renin-angiotensin-aldosterone system. Although all of the calcium entry blockers effectively lower blood pressure, none adversely affects renal function; glomerular filtration rate and effective renal plasma flow are maintained. Diltiazem may increase glomerular filtration rate via attenuation of the intrarenal effects of angiotensin II or norepinephrine. Although diltiazem and nifedipine increase salt and water excretion on a short-term basis, none of the calcium entry blockers produces a clinically significant sustained effect on salt and water excretion; serum electrolytes, urinary sodium and potassium excretion, body fluid composition and body weight are unchanged. Thus, calcium entry blockers can be expected to assume a prominent role in the treatment of hypertension because of their ability to lower blood pressure while preserving renal perfusion and function.

Animals

Nortriptyline-induced severe hyperventilation.

A 61-year-old man with end-stage renal disease developed severe hyperventilation following nortriptyline hydrochloride usage for depression. He required mechanical ventilation and paralysis to correct severe respiratory alkalosis. To our knowledge, nortriptyline usage has not been previously associated with hyperventilation.

Alkalosis, Respiratory