For the treatment of mild to moderate hypertension, as an adjunct in the treatment of congestive heart failure (CHF), to improve survival following myocardial infarction (MI) in individuals who are hemodynamically stable and demonstrate symptoms of left ventricular systolic dysfunction or signs of CHF within a few days following acute MI, and to slow progression of renal disease in hypertensive patients with diabetes mellitus and microalbuminuria or overt nephropathy.
There are two isoforms of ACE: the somatic isoform, which exists as a glycoprotein comprised of a single polypeptide chain of 1277; and the testicular isoform, which has a lower molecular mass and is thought to play a role in sperm maturation and binding of sperm to the oviduct epithelium. Somatic ACE has two functionally active domains, N and C, which arise from tandem gene duplication. Although the two domains have high sequence similarity, they play distinct physiological roles. The C-domain is predominantly involved in blood pressure regulation while the N-domain plays a role in hematopoietic stem cell differentiation and proliferation. ACE inhibitors bind to and inhibit the activity of both domains, but have much greater affinity for and inhibitory activity against the C-domain. Trandolaprilat, the active metabolite of trandolapril, competes with ATI for binding to ACE and inhibits and enzymatic proteolysis of ATI to ATII. Decreasing ATII levels in the body decreases blood pressure by inhibiting the pressor effects of ATII as described in the Pharmacology section above. Trandolaprilat also causes an increase in plasma renin activity likely due to a loss of feedback inhibition mediated by ATII on the release of renin and/or stimulation of reflex mechanisms via baroreceptors.
Most likely clinical manifestations of overdose are symptoms of severe hypotension. Most common adverse effects include cough, headache and dizziness. The oral LD<sub>50</sub> of trandolapril in mice was 4875 mg/kg in males and 3990 mg/kg in females. In rats, an oral dose of 5000 mg/kg caused low mortality (1 male out of 5; 0 females). In dogs, an oral dose of 1000 mg/kg did not cause mortality and abnormal clinical signs were not observed.
~ 40-60% absorbed; extensive first pass metabolism results in a low bioavailability of 4-14%
The elimination half lives of trandolapril and trandolaprilat are about 6 and 10 hours, respectively, but, similar to all ACE inhibitors, trandolaprilat also has a prolonged terminal elimination phase that involves a small fraction of administered drug. This likely represents drug binding to plasma and tissue ACE. The effective half life of elimination for trandolaprilat is 16-24 hours.
After oral administration of trandolapril, about 33% of parent drug and metabolites are recovered in urine, mostly as trandolaprilat, with about 66% in feces.
* 18 L
* 52 L/h [After approximately 2 mg IV doses]