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level: Level 4

Questions and Answers List

level questions: Level 4

QuestionAnswer
the process by which a drug reversibly leaves the bloodstream and enters the instertitium (extracellular fluid) and the tissues.DRUG DISTRIBUTION
In Drug distribution, many drugs bind to __, including albumin, with an equilibrium between bound and free molecules Competition between drugs for plasma protein binding sites may increase the "__,“ possibly enhancing the effects of the drug displacedplasma proteins, free fraction
What are the Special Barriers to Distribution?1 Placental (most small molecular weight drugs cross the placental barrier; fetal blood levels are usually lower than maternal) 2 Blood-brain (permeable only to lipid-soluble drugs or those of very low molecular weight)
• Concentration of drug at the receptor site • Commonly measured in the blood (Exception for topical agents)EFFECTIVE DRUG CONCENTRATION
Plasma concentration is a function of– the rate of input of the drug (by absorption) into the plasma – the rate of distribution – and the rate of elimination
Pharmacokinetics TWO BASIC PARAMETERS1 CLEARANCE 2 VOLUME OF DISTRIBUTION
the measure of the ability of the body to eliminate the drugCLEARANCE
the measure of the apparent space in the body available to contain the drug.VOLUME OF DISTRIBUTION
The ratio of the amount of drug in the body to the drug concentration in the plasma or bloodVolume of distribution -Can be affected by liver and kidney disease
METABOLISM OF DRUGS Three major routes:– Hepatic metabolism – Biliary metabolism – Urinary metabolism
Metabolism (Biotransformation) PHASES1) Phase I (Functionalization) – Redox Reactions and hydrolysis. 2) Phase II (Conjugation) – Attacks certain drugs with existing functional groups and attaches conjugate molecules
What kind of reaction is common for neonates?Sulfation
Metabolism (Biotransformation) May be affected by• Drug Interactions due to inducers, inhibitors, and substrates • Genetic factors • Disease states DRUG WITH INDUCER - FASTER DRUGS WITH INHIBITOR - SLOWER
an inactive precursor chemical that is readily absorbed and distributed and then converted to the active drug by biologic processes inside the body Can be Active to Active, Inactive to ActiveProdrug
EXCRETION; Renal elimination of drugs:– Glomerular filtration – Proximal tubular secretion – Distal tubular reabsorption
Excretion process1 Glomerular filtration of water and unbound drugs and metabolites 2 Active tubular secretion of acidic and basic drugs and metabolites 3 Active reabsorption of acidic and basic endogenous compounds and passive reabsorption of lipophilic drugs 4 Urinary excretion of drugs and metabolites that are filtered and or actively secreted and not reabsorbed