Pharmacokinetics Flashcards
what is pharmacokinetics
what the body does to the drugs
name local routes.. less or more S/E than systemic?
creams, pessaries, eye drops, nebs, inhalers.. less S/E
name systemic routes.. smaller or larger dose needed for same effect as local route?
oral, patches, IV,IM,SC ..larger dose needed
at least how many 02L for nebs?
6L/MIN
name the 4 processes in pharmacokinetics
absorption, distribution, metabolism, excretion/elimination
absorption for oral admin route..
GI tract wall, capillary wall, bloodstream.
absorption is dependent on bioavailability which is…?
(a fraction of 1, IV 1/1) the amount of drug that has reached circulation and is available to all tissues.
absorption is dependent on bioavailability which is…?
(a fraction of 1, IV 1/1) the amount of drug that has reached circulation and is available to all tissues.
absorption is dependent on properties of a drug - dec. water solubility if lipid soluble (hydrophobic)… inc. solubility if ionised .. known as …
hydrophillic
where is first pass metabolism and by what enzymes?
liver - cytochrome p450 system
how can first pass effect be avoided?
other routes - IV, sublingually
pathway of drug given orally
absorption (stomach & Intestines), heptaic portal vein, liver, systemic circulation
Maximum safe concentration (MSC)
___________________________ =?
Minimum effective concentration (MEC)
Therapeutic Index (TI) or ratio. the wider the index the less adverse reactions and risk of toxicity.
pathway of drug given orally
absorption (stomach & Intestines), heptatic portal vein, liver, systemic circulation
Maximum safe concentration (MSC)
___________________________ =?
Minimum effective concentration (MEC)
Therapeutic Index (TI) or ratio. the wider the index the less adverse reactions and risk of toxicity.
what is distribution?
when the drug is distributed to target tissues via sytemic circulation
what is distribution?
when the drug is distributed to target tissues via sytemic circulation
what is a teratogen and name an example
harmful to growing foetus - thalidamide
how do drugs travel in the bloodstream?
bings to plasma proteins
- unbound/free drug = active
- bound = increases half life ‘inactive’
how do drugs travel in the bloodstream?
bings to plasma proteins
- unbound/free drug = active
- bound = increases half life ‘inactive’
what is metabolism? .. where?
inactivation of drug for excretion, detoxification .. usually in liver
what is metabolism? .. where?
inactivation of drug for excretion, detoxification .. usually in liver
name enzyme in liver involved in metabolism of drugs
cytochrome p450
what is a ‘pro-drug’
drug only effective after activation by liver enzyme
