Pharmacology Assignment Example | Topics and Well Written Essays - 1250 words - 2

Pharmacology - Assignment Example In these tissues, CD243 helps protect the tissue from cytotoxic effects of toxins. Further still, P-gp promotes the excretion of drugs into the bile ducts of the liver, excretion of drugs into urine, and excretion of drugs into the capillaries of the BBB (Schinkel et al., 1995; Horn & Philip, 2004). Different studies have been conducted in which various inhibitors of P-gp (MDR1) have been used to evaluate the bioavailability of drugs following the inhibition of MDR1. In one such study, the investigators used Dipyridamole to inhibit MDR1. The study hypothesized that inhibition of dipyridamole inhibition will result in increased bioavailability of digoxin. The study found out that dipyridamole increases the absorption of digoxin at the intestine and the plasma levels of digoxin were increased (Celine et al., 2003). In another study, the effect of MDR1 inhibition was measured on the effect of drug interaction between digoxin and quinidine. Quinidine enhances plasma concentration of digoxin by inhibiting MDR1. The co-administration of quinidine and digoxin resulted in an elevated concentration of digoxin and reduced excretion in urine (Fromm et al., 1999). Another study on mice indicated that absence of MDR 1 resulted in reduced excretion of digoxin (Funakoshi et al., 2003), dexame thasone, and Cyclosporin A (Schinkel et al., 1995). Rifampin is an inducer of CD243. A study conducted to determine the bioavailability of digoxin following the administration of rifampin revealed that the plasma concentration of digoxin dropped significantly. The drop has been accounted for by the understanding that rifampin induces the activity of MDR 1. JP 789 inhibits the action of MDR1 and therefore it can be hypothesized that during the interaction study, JP789 will result in an increase in the plasma concentration of digoxin and its reduced excretion in kidney