Which property makes bethanechol suitable for oral administration?

Which property makes bethanechol suitable for oral administration?

• A. Rapidly degraded by stomach acid
• B. Requires injection due to instability
• C. Non-selective at muscarinic and nicotinic receptors
• D. Very stable from beta-methyl and urethane groups so can be used orally

Answer: (D)

Oral effectiveness comes from a compound staying intact long enough to be absorbed and reach its target receptors. Bethanechol is designed with features that resist enzymatic breakdown and chemical degradation in the GI tract. The beta-methyl group adds steric hindrance, slowing hydrolysis by acetylcholinesterase, while the urethane (carbamate) linkage is more resistant to enzymatic cleavage than a plain ester. These factors together give Bethanechol enough stability to be taken by mouth and stimulate peripheral muscarinic receptors effectively. The other options describe properties that would undermine oral use—rapid stomach acid degradation or needing injection due to instability would prevent oral efficacy, and non-selectivity at muscarinic/nicotinic receptors doesn’t address oral stability.

Oral effectiveness comes from a compound staying intact long enough to be absorbed and reach its target receptors. Bethanechol is designed with features that resist enzymatic breakdown and chemical degradation in the GI tract. The beta-methyl group adds steric hindrance, slowing hydrolysis by acetylcholinesterase, while the urethane (carbamate) linkage is more resistant to enzymatic cleavage than a plain ester. These factors together give Bethanechol enough stability to be taken by mouth and stimulate peripheral muscarinic receptors effectively. The other options describe properties that would undermine oral use—rapid stomach acid degradation or needing injection due to instability would prevent oral efficacy, and non-selectivity at muscarinic/nicotinic receptors doesn’t address oral stability.