Atlas · Plate VIII · Pharmacology and Local Anesthesia · 01
Drug principles
Pharmacokinetics is what the body does to a drug: absorption, distribution, metabolism (mainly in the liver) and excretion (mainly by the kidneys). Pharmacodynamics is what the drug does to the body. Half-life sets how long a drug lingers, potency differs from efficacy, and a narrow therapeutic index (warfarin, digoxin, lithium) needs close monitoring. Antagonists such as naloxone and flumazenil block receptors.
High-yield facts · 8
- Pharmacokinetics is what the body does to a drug (absorption, distribution, metabolism, excretion); pharmacodynamics is what the drug does to the body.S51
- Half-life is the time for plasma level to fall by 50%; about 4-5 half-lives clear most of a drug.S51
- The liver is the main site of drug metabolism (cytochrome P450); the kidneys are the main route of excretion.S51
- First-pass effect: oral drugs pass through the liver before reaching circulation, lowering bioavailability.S51
- Potency is the dose needed for an effect; efficacy is the maximum effect possible.S51
- Therapeutic index = toxic dose / effective dose; a narrow index (e.g., warfarin, digoxin, lithium) needs close monitoring.S51
- An agonist activates a receptor; an antagonist blocks it (e.g., naloxone for opioids, flumazenil for benzodiazepines).S51
- Routes from fastest to slowest onset: IV, inhalation, IM, subcutaneous, oral.S51
Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.