ADME - Sheet1 Flashcards
What is absorption in pharmacokinetics?
The movement of a drug from the site of administration into the blood.
What determines drug action during absorption?
The rate and amount of absorption.
What happens with a higher absorption rate?
Faster onset of drug effects.
What happens when a drug is absorbed quickly and well?
It produces effects quickly and elicits a better response.
What factors affect absorption?
Rate of dissolution, surface area (e.g., villi), blood flow, lipid solubility, and pH partitioning.
What are the routes of administration under absorption?
Enteral (via GI tract), parenteral (by injection), and other routes.
What does “enteral” refer to?
Administration via the GI tract, including oral (PO), NG tubes, and gastrostomy tubes.
What forms of medication are administered enterally?
Tablets/capsules, enteric-coated, sustained/extended-release, sublingual, and liquids/solutions.
What does “parenteral” refer to?
Administration by injection, such as IV, IM, and subcutaneous routes.
What are some other routes of drug administration?
Topical, transdermal, inhaled, suppository (rectal or vaginal), and direct injection (e.g., heart, joints, nerves, CNS).
What is distribution in pharmacokinetics?
The movement of drugs through the body after absorption.
What are the three factors determining drug distribution?
- Blood flow to tissues, 2. Exiting the vascular system, 3. Entering cells.
What is metabolism in pharmacokinetics?
The process of altering the structure and function of drugs, nutrients, vitamins, and minerals.
Where does most drug metabolism occur?
In the liver.
What is the role of hepatic microsomal enzymes?
They metabolize drugs, with cytochrome P450 (CYP) being the primary enzyme group.
How does the CYP system help eliminate drugs?
By making them water-soluble so they can be excreted by the kidneys and urine.
What are the three roles of drugs in the CYP system?
- Substrates (rely on CYP for metabolism), 2. Enzyme inhibitors (block CYP activity), 3. Enzyme inducers (accelerate metabolism).
What happens when a drug acts as a CYP enzyme inhibitor?
It can lead to toxic drug levels by preventing metabolism of substrate drugs.
What happens when a drug acts as a CYP enzyme inducer?
It accelerates metabolism, decreasing drug levels and potentially reducing effectiveness.
What is the first-pass effect?
When an oral drug is metabolized to an inactive form in the liver before reaching target cells.
Why is nitroglycerin given sublingually?
To avoid the first-pass effect in the liver.
What are special considerations in drug metabolism?
Age, induction of drug-metabolizing enzymes, first-pass effect, nutrition status, competition among drugs, and enterohepatic recirculation.
What is enterohepatic recirculation?
The recycling of drugs and metabolites between the liver and intestines, prolonging their presence in the body.
What is excretion in pharmacokinetics?
The process of removing drugs and their metabolites from the body.
