NURS8024 PHARM EXAM 1 ACTUAL LATEST

NURS8024 PHARM EXAM 1 (ACTUAL / ) LATEST

QUESTIONS WITH VERIFIED 100% CORRECT ANSWERS.

Processes of drug metabolism Phase 2 - --Answers---• involves conjugation - reaction in which a large chemical group is attached to the molecule to increase solubility and facilitate excretion of the metabolite from the body

Whether drugs undergo both phase 1 and 2 of metabolism or only one of the phases depends on - --Answers---the chemical nature of the drug

Phase 1 drug metabolism reactions involve - --Answers--- CYP450 system

CYP450 System - --Answers---Serves to convert lipophilic molecules into more polar molecules

Phase 1 metabolism - --Answers---can increase, decrease, or leave drug pharmacologic activity unchanged

Lipid soluble metabolites must be synthesized in the - -- Answers---Liver via Phase 1 & 2 metabolism 1 / 4

Kidneys are typically unable to effectively eliminate - -- Answers---lipophilic drugs due to their increased ability to cross cell membranes

Cytochrome P450 System - --Answers---• Comprised of many families of isoenzymes • found in most cells- much higher amounts in liver & GI tract • Various mutations result in increased or decreased ability to metabolize certain drugs • Six most important

• CYP3A4, CYP2D6, CYP2C9/10, CYP2E1, CYP1A2

• Important to metabolism of many endogenous compounds and biotransformation of exogenous substances (xenobiotics)

Enzymes of drug metabolism are influence by - --Answers---• Genetics • Diet - proteins, carbs, flavonoids, • Inducers - which ↑ enzyme synthesis • Inhibitors - which ↓ enzyme synthesis

Inducers - --Answers---Drugs can be inducers of certain CYP isozymes 2 / 4

• Results in increased biotransformation of drug • →Decreased blood concentrations • →Decreased drug activity if metabolite is inactive • →Increased drug activity if metabolite is active • →Decreased therapeutic drug effect

• Ex: Rifampin decreases HAART therapy- decreased

suppression of HIV virus

Inhibitors - --Answers---• Inhibition of CYP isozyme activity is also important • Most through competition for isoenzyme • Many drugs inhibit one or more biotransformation pathways

of warfarin (ex: omeprazole- inhibits 3 pathways)

• Warfarin + omeprazole= ↑ warfarin level • Increased drug levels can occur over time → prolonged drug effects → increased drug toxicities (Grapefruit juice inhibits

CYP3A4)

• Cimetidine- blocks metabolism of theophyline, clozapine, warfarin

Phase 2 reactions (Conjugation reactions) - --Answers---• If Phase I metabolites too lipophilic to be retained in kidney tubules → need additional conjugation 3 / 4

• Require additional conjugation w/ endogenous substrate (glucuronic acid, sulfuric acid, acetic acid, amino acid) • Results in more polar and water soluble therapeutically inactive substances → then able to be eliminated by the kidneys.....• Neonates are deficient in this conjugating system

If phase one metabolism is effective - --Answers---The metabolites will be excreted through the kidney.

Routes of drug elimination - --Answers---- Kidneys

• Liver
• Intestine
• Lungs
• Milk
• Saliva
• Sweat

Qualitating renal drug elimination - --Answers---• Clearance = renal plasma flow x extraction ratio

Extraction ratio - --Answers---decline of drug concentration in the plasma from the arterial side to the venous side of the kidney

• / 4