Intro To Pharmacology Flashcards
Define neuropharmacology
Study of drug induced changes in the nervous system
Define psychopharmacology
Study of drug induced changes is cognition and behaviour and mood
Drug action
Specific molecular changes produced when drug binds to receptor
Drug effect
Widespread alterations in physiological or psychological functioning. Site of action can be very different than site of effect
Therapeutic effects vs side effects
Desired effects vs all other effects
Specific drug effects
Effects based on physical and biochemical activity of drug receptor interaction
Nonspecific drug effects
Effects based on individuals unique characteristics (i.e. Age, gender, etc.)
Placebo
Nonspecific drug effect that can have therapeutic and side effects despite being a pharmacologically inert substance
Naloxone
Opioid antagonist, also blocks placebo effect
Cholecystokinin
Peptide In GI, modulates nocebo effect
Inhibits opioids
Dopamine
Parkinson’s patients respond to placebo effects of treatments, positive and negative suggestions correlate with endogenous dopamine concentrations
Pharmacokinetics
Factors contributing to bioavailability (administration, absorption, distribution, binding, inactivation, and excretion of a drug)
Pharmacodynamics
Study of physiological and biochemical interactions of s drug with the target tissue responsible for drugs actions.
First pass metabolism
Chemicals passed via portal vein to liver to be metabolized, reduces bioavailability
Oral admin
Slow, variable absorption, safer
IV admin
Rapid, accurate concentration, more dangerous (OD, sterile)
IM admin
Slow, even absorption
Subcutaneous admin
Slow, prolonged absorption
Inhalation
Large SA, rapid onset
Topical admin
Localized action and effects
Transdermal
Controlled and prolonged absorption
Epidural admin
Bypass BBB, rapid CNS effect. Irreversible
Lipid soluble drug absorption
Pass through plasma membrane easily
Ionization of drugs
More ionization=less absorption
Depends on pKa and pH
Weak acids ionize better in alkaline environments and weak bases in acidic
Lidocaine
Blocks sodium channels, results in inhibition of inhibitory, then excitatory CNS pathways
Blood brain barrier
Capillaries structured differently to restrict access of molecules
Astrocytes help maintain tight junctions
Incomplete at area postrema and median eminence
Depot binding
Inactive sites where drugs can bind and be released later.
Competitive binding to a depot may increase concentrations of displaced drugs
First order kinetics
Exponential elimination of free drug, 50% of drug is removed each time interval
Concentration dependent
Half life
Amount of time required to remove half the drug from a system
0 order kinetics
Constant removal rate of drug regardless of concentration
Steady state plasma level
Point at which drug absorption is equal to drug metabolism
Approached after time period equal to five half lives
Type 1/phase1 biotransformation
Nonsynthetic modifications; redox, hydrolysis. Usually decreases activity, but can produce active metabolites
Type 2/ phase2 biotransformations
Synthetic modifications that require conjugation of the drug with a small molecule (ie methyl group) to produce less lipid soluble molecule (ionic)
Microsomal enzymes
Enzymes in liver with low specificity to metabolize xenobiotics
Cytochrome p450
Enzyme induction
Drug increases enzymes concentration, can also effect non target drug concentrations
Enzyme inhibition
Drugs inhibiting action of enzymes ie MAOi
Factors influencing drug metabolism
Enzyme induction/inhibition
Drug competition
Individual differences
Up regulation
Increase in amount of receptors for given drug
Down regulation
Reduction in number of receptors
Dose response curve
Amount of effect for a given drug concentration
Potency
Absolute amount of drug needed for effect
Efficacy
Ability of drug to perform desired action
Therapeutic index
ED50/LD50 margin of safety between how effective drug is and how much drug is needed for a lethal dose. Larger=more safe
What is pharmacology?
Scientific study of the actions of drugs and their effects on living organisms
Physiological antagonism
Two drugs produce opposite effects and reduce each other’s effectiveness
Additive effects
Combined drug effects equals sum of each drug alone
Potentiation
Combined drug effects are greater than the sum of individual drug effects
Drug tolerance
Diminished response to drug administration after repeated exposure
Sensitization
Enhancement of particular drug effects following repeated exposure to the drug
Metabolic tolerance (drug disposition)
Repeated use of drug reduces amount of drug in target tissue (ie enzyme induction)
Pharmacodynamic tolerance
Changes in nerve cell function compensate for continued presence of drug ie amount of receptors
Behavioural tolerance
Context specific tolerance
Proglumide
CCK antagonist, potentiates analgesic placebo effect
