Tachyphylaxis [chapter]

Nadia Webb
2017 Encyclopedia of Clinical Neuropsychology  
Definition Tachyphylaxis is the continued or repeated exposure to a drug that may lead to a weakened pharmacological response. This is presumed to be a consequence of diminished receptor sensitivity in response to consistent stimulation by a drug agonist, which produces a diminished pharmacological response in consequence. This is distinct from tolerance. This desensitization process can be a consequence of a decrease in the number of receptors or an attenuation of the response because the drug
more » ... se because the drug has promoted neurotransmitter release in excess of presynaptic production. The presence of certain enzymes can limit cyclic AMP-based signaling, disrupt second messenger systems, and diminish the availability of receptors at the cell membrane. Tachyphylaxis appears to be an idiosyncratic process. For example, repeated administration of tyramine, which is a protein precursor to norepinephrine, tends to produce tachyphylaxis. Repeated administration of norepinephrine does not, and reverses tachyphylaxis to tyramine for reasons unknown.
doi:10.1007/978-3-319-56782-2_1752-2 fatcat:k5eo3uyiufdnpgg64qskmpgroy