chapter 2 flashcards 115

Cells are dynamic factories; they take in raw materials, manufacture and deliver products, and differ by tissue.
Common cellular characteristics: exchange materials with environment, obtain energy from nutrients, synthesize complex molecules, reproduce, communicate via biologic chemicals.

Absorption: Process from drug entry into body to bloodstream entry.
- Onsets drug action.
- Affected by: dosage form, route, administration site blood flow, GI function, food, other drugs.
Distribution: Transport of drug molecules by blood and tissue fluids to action, metabolism, and excretion sites.
- Dependent on blood circulation adequacy.
- Affected by: protein binding, blood–brain barrier, pregnancy, lactation.
Metabolism (Biotransformation): Inactivation or chemical alteration of drugs.
- Drugs change to inactive/active metabolites or prodrugs.
- Enzymes are in kidneys, liver, RBCs, plasma, lungs, GI mucosa.
- Affected by enzyme induction and inhibition.
Excretion: Elimination of medication from the body.
- Requires adequate function of circulatory system, kidneys, bowel, lungs, skin.

Laboratory measurement of drug amount in blood at a specific time.
Reflects dosage, absorption, bioavailability, half-life, metabolism, excretion rates.
Minimum Effective Concentration (MEC): Must be present for efficacy.
Toxic Concentration: Excessive drug level causing adverse effects, due to large single dose, repeated doses, or slow metabolism.

Drugs bind chemically with receptor cells, leading to:
- Activation, inactivation, or alteration of intracellular enzymes.
- Changes in cell membrane permeability.
- Modification of neurohormone synthesis, release, or inactivation.
- Involves agonists and antagonist drugs.

Few drugs act without receptor sites; examples include antacids, osmotic diuretics, some anticancer drugs, metal chelating agents.

Factors: Dosage (frequency, size, number), route of administration, drug–diet and drug–drug interactions.
Increased Effects: Additive effects, synergism, interference, displacement.
Decreased Effects: Antidote medication, decreased intestinal absorption, increased metabolism rate.

Age, body weight, pharmacogenomics, genetics, ethnicity, gender, pharmacogenetics, preexisting conditions, psychological considerations, tolerance, cross-tolerance.

Any undesired responses to medication administration.
Can occur with usual therapeutic dosing, more likely with high dosing, specific drugs, and in older adults on multiple drugs.

Results from excessive medication, potentially damaging tissues.
Causes: single large dose, prolonged ingestion of smaller doses, involving various drug types.
Treatment Goals: Prompt treatment, supporting/stabilizing vital functions, preventing further damage (reducing absorption, increasing elimination, administering antidotes).