Factors Modifying Drug Action

Factors Modifying Drug Action

Describe The Factors Modifying The Drug Response Giving Suitable Examples.
Or
Describe Various Factors Modifying Drug Action.
Answer:

Factors Modifying Drug Action

Variation in the response to the same dose of the drug, in different patients, and even in the same patient on different occasions is a rule rather than expansion.

The various factors that can be modifying drug effect are:

• Body size: The larger the size more can be the dose required to produce the same effect.
• Age: Infants, children, and elders are more sensitive to drug effects because it depends on the process of metabolism and excretion of the drug and they do have not well-developed systems. While in later they deteriorate with the advancing age.
• Sex: Females have smaller body sizes and require doses of the lower side of the range.
  • Androgens are unacceptable to women and estrogen to men.
  • Gynecomastia is a side effect that occurs only in men not in women.
• Genetic variation: It leads to a change in the rate of drug metabolization which increases or decreases the quantity of metabolizing enzyme.
• Routes of administration: They govern the speed and intensity of drug response, for example, magnesium sulfate given orally acts as a laxative. Applied locally act as an anti-inflammatory and when given IV it produces CNS depression.
• Environmental factors and time of administration: Several environmental factors affect the drug response. Exposure to insecticides, carcinogens, and tobacco smoke induces drug metabolism. Hypnotics taken at night and in quiet, familiar surroundings may work more easily.
• Psychological factors: The efficacy of a drug can be affected by the patient’s beliefs, attitudes, and expectations.
  This is particularly applied to centrally acting drugs, for example, a nervous and anxious patient requires a more general anesthetic.
• Pathological state: Diseases affecting GIT, liver, kidney, and heart can affect the absorption, metabolism, distribution, and excretion of drugs.
• Other drugs: When two drugs are given simultaneously they may modify response to each other by synergism or antagonism.
• Tolerance: When some drugs are given repeatedly, to produce the same response, a higher dose of the drug is required, for Example. morphine and diazepam.