Question

CD12 [Jul97] [Mar02] [Jul02] [Jul04] Clonidine:

A. Elimination half-life of 3 hours (??or 3 to 6 hrs)
B. Excreted 50% unchanged in the urine (or 50% renally excreted)
C. Oral bioavailability 50%
D. Cannot be absorbed topically
E. Is highly protein bound

Answer 1

Clonidine has an elimination half-life of approximately 12 to 16 hours, is about 50 to 70% excreted unchanged in the urine, has a high oral bioavailability of around 75 to 80%, can be absorbed topically, and is moderate protein bound with 20 to 40% being bound to plasma proteins.

Step-by-step explanation:

The pharmacokinetic properties of clonidine are as follows: Clonidine has an elimination half-life of approximately 12 to 16 hours, which is longer than the 3 to 6 hours suggested in the question. This means that it takes about 12 to 16 hours for the concentration of clonidine in the blood to reduce by half. Moreover, clonidine is indeed excreted in the urine, with about 50 to 70% of a dose being eliminated unchanged. Its oral bioavailability is high, typically around 75 to 80%, meaning that a large proportion of the drug is absorbed into the bloodstream when taken orally. Contrary to option D, clonidine can be absorbed topically; in fact, it is available as a transdermal patch. Lastly, clonidine is moderately protein-bound in the plasma, with about 20 to 40% of the drug being protein-bound, not 'highly' as would be suggested by being more than 90% bound.