Amantadine used prophylactically against influenza A2, is thought to act by? (LQ)
|A||Presenting production of viral capsid protein|
|B||Preventing virion release|
|C||Preventing penetration of the virus into the host cell|
|D||Preventing uncoating of viral DNA|
a. Amantadine mechanism of action involves inhibition of uncrating of the influenza A viral DNA. The primary target is the membrane M2 protein.
b. The drug does not affect penetration and DNA-dependent RNA polymerase activity Amantadine both reduces the frequency of illness and diminishes the serologic response to influenza infection.
c. The drug has no action, on influenza B. As a weak base, amantadine buffers the pH of endosomes, thus blocking the fusion of the viral envelope with the membrane of the endosome.
This causes a normal adrenal cortex to synthesize increased amounts of 17- hydroxylated steroids, which can be measured in the urine. However, patients who have disease of the hypothalamico-pituitary axis do not produce ACTH in response to metyrapone.
As a result, we find no increased levels of the steroids in the urine. Before administering metyrapone we need to test responsiveness of the adrenal cortex to respond to administration of ACTH.