Flashcards in Intro Deck (76):
Any substance acting on a biological system that can bring about a change in biological function through its chemical actions.
Actions of drug on the body.
PharmacoDynamics: Drug --> body
Actions of the body on the drug.
PharmacoKinetics: Katawan --> drugs
Lightest drug in terms of molecular weight?
Lithium. MW 7 .
Used for bipolar disorders.
WOF nephrogenic diabetes insipidus
Alteplase. MW 50,000.
Anticoagulant of choice in pregnancy?
Heparin. It cannot cross the placenta because of its large size.
Vs warfarin that can cross placenta baby bleeds.
A hepe named PiTT with a large belly.
Heparin is large. i: intrinsic factor
MOA: increases antithrombin III. Monitored with PTT.
Antidote: protamine sulfate
Covalent > ionic > hydrophobic
Cholinergic toxicity. DUMBELLS
Diarrhea, Urination, Miosis, Bronchocospasm,
Emesis, Lacrimation, Lethargy, Salivation
Antidote to organophosphate poisoning?
Pralidoxime but only for the first 6-8 hours. After that covalent bonds can no longer be broken by it.
Atropine may also be used.
Movement of drug molecules into and within biological environments.
Components of pharmocoKinetics?
Absorption, Distribution, Metabolism, Elimination
Vitamin B12 is bound to?
Iron is bound to?
Transferrin for transport
Ferritin for storage
Fick's law of diffusion?
Absorption is faster through thinner membranes and in areas with larger surface area.
Henderson hasselbalch dissociation of weak acids
Protonated acid more lipid soluble, crosses biological membranes easier, unprotonated acid more water soluble, better clearance.
Henderson hasselbalch dissociation of weak bases
Unprotonated base more lipid soluble, better at crossing biological membranes.
Protonated base more water soluble, better clearance
Excretion of a weak acid may be accelerated by?
Alkalinizing urine with bicarbonate
Excretion of weak base accelerated by?
Acidifying urine with ammonium chloride.
First pass effect?
Drug is metabolized in the gut wall, the liver, and the portal circulation before it reaches the bloodstream.
Which quadrant of the buttocks is safest for IM drug administration?
Superolateral is safest.
Inferomedial WOF sciatic nerve
Lingual vein --> IJV --> brachiocephalic (innominate) vein --> SVC --> RA
Rectal route with first pass
If superior rectal vein from IMV --> portal vein, thus first pass
Acute inflammation --> drying agents
Chronic inflammation --> lubricating agents
Transfer from site of administration to blood stream
Leaves blood stream to enter target organ
Acidic drugs --> albumin
Basic drugs --> orosomucoid
Termination of drug action
Release of drug and metabolites through urine, stool etc
Rate of elimination is proportionate to concentration. Decrease by 50% for every half life decrease. Exponential decrease. Most common type
Rate of elimination is constant regardless of concentration. Decrease is linearly.
Zero order elimination
Drugs that follow zero order kinetics
Warfarin, Heparin, Aspirin, Tolbutamide, Phenytoin
Kd, EC50, Emax
Kd concentration required to bind half of the receptors
ED50, TD50, LD50
ED50 median effective dose
TD50 median toxic dose
LD50 median lethal dose
Maximal effect an agonist can produce if the dose is taken to very high levels
Amount of drug needed to produce a given effect.
Graded dose dose required to produce 50% of the maximal effect.
Quantal dose response ed50 ld50 td50
Capable of fully activating the receptor system when bound.
High concentrations result in all receptors being activated
Produces less than the full effect even when the agonist has saturated all of the receptors.
Acts as an inhibitor when mixed with full agonist.
Blocks or dampens drug response in the presence of an agonist
Binds reversibly, does not activate the effector system.
Shifts curve to the right. Increases ed50 decreased potency.
Can be overcome by adding more agonist
Competitive or reversible antagonist
Causes downward shift if the curve. Decreased efficacy Emax, same potency.
Not overcome by adding more agonist
Non-competitive or irreversible antagonist
Binds to a different receptor
Produces an effect opposite to that produced by the drug it is antagonizing.
Interacts directly with the drug being antagonized to remove it or to prevent it from binding
Terazosin vs. norepinephrine
Competitive or reversible antagonist
Phenoxybenzamine for pheochromocytoma
Non competitive irreversible antagonist
Histamine and epinephrine
Propranolol and thyroid hormone
Dimercaprol for heavy metal/lead poisoning
Pralidoxime for organophosphate poisoning
Tachyphylaxis responsiveness diminishes, frequent exposure results in short-term dimunition
MED Loves CNN in HD
Metoclopromide, Ephedrine, Dobutamine, LSD,
Calcitonin, Nitroglycerin, Nicotine, Hydralazine, Desmopressin
Reversed by depletion of missing substrates
Idiosyncratic drug responses
Chloramphenicol and aplastic anemia
Allopurinol and cataracts
Drug eliminated with first-order kinetics, clearance is constant
Elimination is proportional to concentration
Drugs eliminated with zero order kinetics clearance is constant
Bioavailability is fraction of administered dose reaching systemic circulation.
It is determined by computing the area under the plasma concentration curve.
Maintenance dose computation
The Vd or volume of distribution is not in voiced in calculating for maintenance dose
Loading dose computation
Does not include clearance
Phase 1 reactions convert the parent drug to a more water-soluble polar product.examples are
HORD of phase 1
Hydrolysis, Oxidation, Reduction, Deamination
75% of drugs are metabolized by
CYP3A4 and CYP2D6
Increased synthesis of cyp450 enzymes and heme. Higher amount of the drug needed due to increased metabolism, excretion.
ETHYL Booba takes PHEN and RIFuses GRISy CARB Shakes
Ethanol, Barbiturates, PHENytoin, RIFampicin, GRISeofulvin, St. John's Wort/Smoking
Most potent enzyme inducers
Carbamazepine phenobarbital phenytoin RIFampicin
Lower doses of a drug are needed, drug stays in the system longer, reduction in blood flow to metabolizing organ
Metabolized to products that irreversibly inhibit the metabolizing enzyme.
Ethinyl estradiol, spirinolactone, allopurinol, PTU
Inhibitors Stop CIber KEds from Eating GRApefruit Q
Isoniazid, Sulfonamide, Cimitedine, Ketoconazole, Erythromycin, Grapefruit juice, Ritonavir, Amiodarone, Quinidine
Human studies display no risk to fetus.
Animal studies do not show risk, but no human studies have been conducted. Or risk in animal studies but none displayed in human studies
Animal studies have shown adverse effects, no human studies done. Potential benefit justifies risk to fetus
Evidence if human fetal risk, but potential benefits justifies risks
Fetal adverse effects demonstrated, risk of fetal effects outweighs any benefit of drug. Absolute contraindications.
Vaginal clear cell adenoCA
Misoprostol as teratogenic
Atrialization of right ventricle. Ebstein's anomaly.
Standard in vitro test for mutagenicity