Rank the following agents used in hypertension from shortest onset of action to longest onset of action (first dose).
Answer with Rationale:
The correct order is B-C-D-A. One of the lesser known question types of the NAPLEX is Ordered-Response. In these questions, you have to rank a group of items in a specific ordered list. It could be anything so paying close attention to wording is important.
Captopril has an extremely short onset and duration of action and prior to longer acting ACE-inhibitors being approved, it was commonly used in practice. Now it is used in some situations to titrate patients to a target ACE-I dose before transitioning to a longer acting agent.
HCTZ has an onset within a few hours of administration.
Amlodipine has an onset of about 6-12 hours and an extended half-life of 30-50 hours on average.
Catapres-TTS is a patch and therefore takes several days to work. Often when transitioning patients from clonidine tablets to a patch you overlap with continued tablet therapy until the patch "kicks in" about day 2 of 3. Typically you dose the Catapres patch once weekly.
It is important to keep in mind that while these agents onsets of action are within hours to days, the complete effect may take weeks to a month to determine. That is why often patients will return to clinic in 1-4 weeks to determine overall benefit from the drug reaching steady state and to fully determine its pharmacokinetic and dynamic effect.
Good luck to everyone out there for Match Day tomorrow!