Pharmacology Chapter 8 - Individual Variation in Drug Responses Flashcards
Factors that influence drug responses are…(4)
Body weight and composition, age, gender, and pathophysiology.
Body weight and composition - more info
drug achieves a higher concentration in smaller people given the same dosage.
Age - more info
infants are very sensitive to drugs, and elderly are very sensitive to drugs due to organ degeneration.
Gender - more info
response is different to same drug and dosage between men and women.
Pathophysiology - drug
how disease affects responses to drugs.
Four pathological conditions -
Kidney, Liver, Acid-Base Imbalance, Electrolyte Imbalance.
Kidney (PC) -
reduce drug excretion
Liver (PC) -
site of drug detoxification and metabolism
Acid-Base imbalance (PC) -
alters absorption, distribution, metabolism, excretion. Drug will accumulate on the side of the membrane where pH favors ionization of drug. Acid/Acid - Base/Base
Altered Electrolyte Imbalance - PC
Electrolytes (K, Na, Ca, MG) are important in cell physiology and function.
Drug tolerance - def
decreased responsiveness to a drug due to repeated drug administration.
Drug tolerant patients require ___ doses to produce the same effects that could be achieved with lower doses.
Higher.
Three Categories of Drug Tolerance -
Pharmacodynamic, Metabolic, and Tachyphylaxis (less response after repeated applications.)
Pharmacodynamic Tolerance -
associated with long-term administration of drugs (such as heroine). patient requires increased doses to produce effects.
Metabolic Tolerance -
tolerance due to accelerated drug metabolism. Induced by synthesis of increased levels of liver enzymes (Barbituates). Increase in dosage of drug to maintain level of drug in blood that is equal to previous non tolerant levels.