It is very essential to understand these two terms and the differences associated with them in order to obtain Drug Response Curves.

POTENCY:(1)

• the content of drug that is required in order to produce a given percentage of its highest effect,regardless of the magnitude of maximal effect.
• A drug may have higher potency but least efficacy, means that the response is seen at very lower doses and remains very small even at higher doses. Drug potency is sometimes an important clinical consideration.(1)
• drug potency depends on both affinity and efficacy of the drug(2)
• Potency is that dose of the drug that is required to produce a specific effect of the given intensity when compared to a standard reference of drug(1)
• potency is the measure of the drug activity expressed in terms of amount that is required in order to produce an effect of the given intensity.(1)
• A highly potent drug for instance(e.g., morphine, alprazolam, chlorpromazine) gives a large response at low concentrations, when compared to a drug of lower potency for instance(ibuprofen, acetylsalicylic acid) evokes a small response at low concentrations. It is proportional to affinity and efficacy.(2)

affinity:it is the ability of the drug to bind to the receptors

EFFICACY:

• Efficacy is the relationship between the receptor occupancy and ability to start a response at molecular, cellular, tissue or system level in the body.(4)
• The response is equal to effect, or (E), and depends on both the drug binding and the drug-bound receptor there by producing a response; hence potency depends on both affinity as well as efficacy.(4)

REFERENCES:

1.http://en.wikipedia.org/wiki/Potency_(pharmacology)(accessed on 30-4-11,11.30 p.m)

2.http://medical-dictionary.thefreedictionary.com/drug+potency(accessed on 30-4-11,11.30 p.m)

3.http://chemiplus.net/dic/Pharmacokinetics%20definition-1324FEF/ (accessed on 30-4-11,11.30 p.m)

4.http://www.answers.com/topic/efficacy (accessed on 30-4-11,11.30 p.m)

5.http://watcut.uwaterloo.ca/webnotes/Pharmacology/page-3.5.html(accessed on 30-4-11,11.30 p.m)"THIS BLOG DOESN'T CONTAIN ANY PLAGIARISED MATERIAL"

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