Often, the effect of a drug gradually diminishes when it is given continuously or repeatedly. Desensitization...
Often, the effect of a drug gradually diminishes when it is given continuously or repeatedly. Desensitization and tachyphylaxis are synonymous terms used to describe this phenomenon. Desensitization is a general issue with extended treatment with GPCR agonists as phosphorylation of the receptor interferes with its ability to activate second messenger cascades, although it can still bind the agonist molecule. Which of the following would likely be true for an agonist drug binding to a receptor that has become desensitized over time? The selectivity of the drug would be increased. The potency of the drug would be increased. The affinity of the drug for the receptor would be reduced. The efficacy of the drug would be reduced.