True about efficacy and potency of drugs: (LQ)
|A||Efficacy is clinically more important than potency|
|B||Height of DRC corresponds to efficacy|
|C||The amount of drugs to produce certain response is called efficacy|
|D||Drugs having similar pharmacological action may have different efficacy|
Go through the difference between potency and efficacy and the options will unfold automatically.
- Drug B is less potent but equally efficacious as drug A.
- Drug C is less potent and less efficatious than drug A, but equally potent and less efficacious than drug B.
- Drug D is more potent than drugs A, B & C, but less efficacious than drugs A & B and equally efficacious as drug C.
- Potency refers to the amount of drug needed to produce a certain response. Drugs A and 8, are said to be more potent than drugs C and D because of the relative positions of their dose response curves along the dose axis.
- Competitive antagonist acts by decreasing the potency of a drug, such that maximal response (efficacy) can still be attained by increasing dose of agonist. Causes rightward shift of ORC.
- Potency refers to the concentration (EC50) or dose (ED50) of a drug required to produced 50% of that drugs maximal effect.
- Potency of a drug depends in part on the efficiency with which drug receptor interaction is coupled to response.
- Efficacy refers to the maximal response that can be elicited by the drug. It refers to the maximum height of the curve. Drugs A and B have higher efficacy as compared to C and D.
- Non competitive antagonist acts by decreasing the efficacy of a drug. Maximal response is suppressed and unsurmountable. Causes flattening of DRC.
- The efficacy of a drug is obviously crucial for making clinical decisions when a large response is needed. It is a more decisive factor in the choice of a drug.
- It may be determined by the drug’s mode of interactions with receptors or by characteristics of the receptor system involved.
Option 'd': Drugs having similar pharmacological action may have different efficacy e.g. Morphine produced a degree of analgesia not to be obtained with any dose of aspirin.