20 Questions
Phase I reactions convert the parent drug to a more polar (water-soluble) or more reactive product by unmasking or inserting a polar functional group such as ´OH, ´SH, or ´NH2. Occurs mostly in the ______
liver
Most drugs are lipid soluble rather than water soluble so they need to be made more ______ to be excreted directly by the kidneys
water soluble
Cytochrome P450 (CYP450) is a superfamily of heme-containing enzymes, functioning as ______
monooxygenases
CYP 1-3 families are involved in drug metabolism. There are many isoforms of CYP enzymes differing from each other in amino acid sequence and specificity of the reactions they catalyse. CYP3A4 accounts for ~55% of drug metabolism. CYP2D6 accounts for ~25% of drug metabolism. There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects
variation in CYP450 Activity
Drug is a chemical substance which produces a biological effect following its administration to the body. Medication or medicine is a drug administered to the body to cure or improve a medical condition. Pharmacokinetics is the study of the movement of drugs and their metabolites through the body. Pharmacokinetic stages: Absorption, Distribution, Metabolism, ______
Elimination (ADME)
Oxidation reaction requires oxygen, ______ (Nicotinamide adenine dinucleotide phosphate) and ______ P450 reductase. The overall cytochrome P450-dependent oxidation reaction can be represented as: $Drug + O2 + ______ + H+ ightarrow Drug-OH + NADP+ + H2O$. There are around 60 CYP enzymes. There are many isoforms of CYP enzymes differing from each other in amino acid sequence and specificity of the reactions they catalyse. CYP3A4 accounts for ~55% of drug metabolism. CYP2D6 accounts for ~25% of drug metabolism. There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects
NADPH
There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects. CYP3A4 accounts for ~55% of drug metabolism. CYP2D6 accounts for ~25% of drug metabolism. There are around 60 CYP enzymes. There are many isoforms of CYP enzymes differing from each other in amino acid sequence and specificity of the reactions they catalyse. CYP 1-3 families are involved in drug metabolism
NADP+ + H2O
Reactions that convert the parent drug to a more polar (water-soluble) or more reactive product by unmasking or inserting a polar functional group such as ´OH, ´SH, or ´NH2. Occurs mostly in liver (most enzymes in the ER of cells). May also occur in the GI tract, kidney, lung and plasma. Converts lipophilic drugs into more polar molecules. Involves oxidation (most common), reduction and hydrolysis reactions
Phase I
Pharmacodynamics is what the drug does to the body. Pharmacokinetics is the study of the movement of drugs and their metabolites through the body. Pharmacokinetic stages: Absorption, Distribution, Metabolism, ______
Elimination (ADME)
Pharmacology is the study of drug interaction with the body. Drug is a chemical substance which produces a biological effect following its administration to the body. Medication or medicine is a drug administered to the body to cure or improve a medical condition. Pharmacokinetics is what the body does to the drug. Pharmacokinetic stages: Absorption, Distribution, ______, Elimination (ADME)
Metabolism
Phase I reactions convert the parent drug to a more polar (water-soluble) or more reactive product by unmasking or inserting a polar functional group such as ´OH, ´SH, or ´NH2. Occurs mostly in the ______
liver
Most drugs are lipid soluble rather than water soluble so they need to be made more ______ to be excreted directly by the kidneys
water soluble
Pharmacokinetic stages: Absorption, Distribution, Metabolism, ______, Elimination (ADME)
Elimination
CYP450 Enzymes require oxygen, NADPH (Nicotinamide adenine dinucleotide phosphate) and NADPHP450 reductase. The overall cytochrome P450-dependent oxidation reaction can be represented as: $Drug + O2 + ______ + H+ \rightarrow Drug-OH + NADP+ + H2O$
NADPH
Pharmacodynamics is what the drug does to the body. Pharmacokinetics is the study of the movement of drugs and their metabolites through the body. Pharmacokinetic stages: Absorption, Distribution, ______, Elimination (ADME)
Metabolism
Cytochrome P450 (CYP450) is a superfamily of heme-containing enzymes, functioning as ______
monooxygenases
Oxidation reaction requires oxygen, ______ (Nicotinamide adenine dinucleotide phosphate) and NADPHP450 reductase. The overall cytochrome P450-dependent oxidation reaction can be represented as: $Drug + O2 + NADPH + H+ \rightarrow Drug-OH + NADP+ + H2O$
NADPH
There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects. CYP3A4 accounts for ~55% of drug metabolism. CYP2D6 accounts for ~25% of drug metabolism. There are around 60 CYP enzymes. There are many isoforms of CYP enzymes differing from each other in amino acid sequence and specificity of the reactions they catalyse. CYP 1-3 families are involved in drug ______
metabolism
Pharmacology is the study of drug interaction with the body. Drug is a chemical substance which produces a biological effect following its administration to the body. Medication or medicine is a drug administered to the body to cure or improve a medical condition. Pharmacokinetics is what the body does to the drug. Pharmacokinetic stages: Absorption, Distribution, ______, Elimination (ADME)
Metabolism
There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects. CYP3A4 accounts for ~55% of drug metabolism. CYP2D6 accounts for ~25% of drug metabolism. There are around 60 CYP enzymes. There are many isoforms of CYP enzymes differing from each other in amino acid sequence and specificity of the reactions they catalyse. CYP 1-3 families are involved in drug ______
metabolism
Study Notes
Phase I Reactions
- Convert the parent drug to a more polar (water-soluble) or more reactive product by unmasking or inserting a polar functional group such as -OH, -SH, or -NH2.
- Occurs mostly in the liver, but can also occur in the GI tract, kidney, lung, and plasma.
Cytochrome P450 (CYP450)
- A superfamily of heme-containing enzymes that function as catalysts.
- CYP 1-3 families are involved in drug metabolism.
- There are around 60 CYP enzymes with many isoforms differing from each other in amino acid sequence and specificity of the reactions they catalyse.
- CYP3A4 accounts for ~55% of drug metabolism.
- CYP2D6 accounts for ~25% of drug metabolism.
Pharmacology
- The study of drug interaction with the body.
- Drug is a chemical substance that produces a biological effect following its administration to the body.
- Medication or medicine is a drug administered to the body to cure or improve a medical condition.
Pharmacokinetics
- The study of the movement of drugs and their metabolites through the body.
- Pharmacokinetic stages: Absorption, Distribution, Metabolism, Excretion (ADME).
- Pharmacokinetics is what the body does to the drug.
Pharmacodynamics
- What the drug does to the body.
Oxidation Reaction
- Requires oxygen, NADPH (Nicotinamide adenine dinucleotide phosphate), and NADPH P450 reductase.
- The overall cytochrome P450-dependent oxidation reaction can be represented as: $Drug + O2 + NADPH + H+ \rightarrow Drug-OH + NADP+ + H2O$.
Genetic Variability
- There is a huge genetic variability in P450 enzymes amongst individuals and races, which can affect drug efficacy and the risk of side effects.
Test your knowledge of drug metabolism with this quiz covering topics such as phase I and phase II metabolism, the cytochrome P450 system, variation in drug metabolism, and specific examples of alcohol and paracetamol metabolism.
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