Drug Disposition Flashcards
Metabolism and excretion combined make what?
Elimination
What is the primary organ of drug metabolism?
Liver
Why must benzylpenicillin be given IV?
unstable in acidic environment of stomach
Why must insulin be given subcutaneously?
As a peptide, it will be degraded by acidic environment in stomach
By what calculation can properties of ionised and unionised drugs be calculated?
Henderson-Hasselbalch
Do acidic drugs become more or less ionised in acidic environment?
Less
What facilitates absorption of weak acids?
stomach lumen
Where does the majority of absorption occur?
small intestine
What is the pH in the duodenum?
neutral
What is the pH in the jejenum and ileum?
slightly alkaline
Drugs administered through what method have 100& systemic availability?
IV
What route of drug entry involves first pass metabolism?
Oral
What route of drug entry is used for nocturnal administration of some drugs?
Rectal
What route of drug entry has rapid onset and needs sterile preparation?
IV
What route of drug has rapid onset of lipid soluble drugs in particular?
Subcutaenous
Which drug routes are ideal for localised effect?
Topical, inhalational
Which drug route method is hardly ever used as it is associated with some dangerous effects?
Intra-arterial
What drug route is good for volatile agents?
Inhalational
Are bound drug molecules able to move between compartments?
No, only free drug molecules can
Can ionised drugs move readily by diffusion?
No, only unionised drugs can
Are drugs evenly distributed in the body?
No
What does a volume of distribution under 5L imply?
drug is retained in vascular compartment
What does a volume of distribution under 15L imply?
Drug retained to extracellular water
What does a volume of distribution of more than 15L imply?
Distribution is throughout total body water
