Exam 1 Flashcards
Drug
a substance that is used primarily to bring about a change in some existing process or state
Psychoactive drug
changes brain function and results in alterations in perception, mood, or consciousness
what substances were used by ancient people?
nicotine, caffeine, morphine, cocaine, and THC
Neuropsychopharmacology
influence of drugs on brain, behavior, and psychological function
4 ways to classify drugs
- Source (natural, synthetic, semisynthetic)
behavioral/ psychological effects (medical/therapeutic use) - Pharmacological action (ex: things that act on GABA)
- Chemical structure
- Legal status
Addiction
- craving, relapse, chronic, inability to control drug use, use despire harm, social/interpersonal problems
- kown as substance use disorder
- NOT physical dependence and withdrawal
Physical dependence
body relies on drug to prevent withrawl due to PHYSIOLOGICAL ADAPTATIONS
craving and relapse are persistent
Binge drinking in men vs women
men: 5+ drinks,
women 4+ drinks
heavy drinking
5 or more binge days out of last 30
what factors shaped drug use and cultural attitudes in the US?
- alcohol temperance moment
- increased addictive potential of drugs due to advances in chemistry and development of syringes
- increased drug availability and luck of drug control law
- medicalization of drug addiction
Anti-Drug Abuse Act of 1986
- increased penalties for drug crimes
- Created big racial sentencing disparity between crack (black) and powder (white) cocaine
Bioavailability
amount of drug available to bind to target sites and illicit drug action
Pharmacokinetics
- absorption, distribution, metabolism, and excretion of drugs (movement)
- affect drug onset, duration, and peak concentration
Pharmacodynamics
biochemical effects of drugs and their mechanism (change in body); action of drug at receptors or targets
what affects absorption?
- route of administration (blood circulation and surface area at site of administration, amount of drug destroyed by digestive/ metabolic processes, transport across membrane)
- drug solubility and ionization
what does fast onset and high peak concentration mean?
short duration
oral (po)
- absorption in gastrointestinal tract (enteral route)
- slow variable (affected by food)
- must be resistant to stomach acids and enzymes
- first-pass metabolism in the liver before entering bloodstream
Slow route; slow absorption
Intranasal
substance does not need to be dissolved (bypasses BBB straight into olfactory bulb)
Sublingual
absorbed by mucous membranes in mouth
Used for rapid adjustment for pain levels
Rectal
absorbed by blood vessels
Injections
- Subcutaneous (SC, sub-Q)
- Intramuscular (IM)
- Intravenous (IV)- rapid and accurate
IV: fast onset; used for abuse
what is distribution and what affects it?
movement from blood to target site (brain)
1. BBB
2. depot binding
BBB
blood brain barrier
selectively permeable (lipophilic) to keep brain environment stable and keep bacteria/viruses out
1. typical capillaries: “leaky”, allow ionized molecules in/out
2. brain capillaries: more selective but lipid-soluble drugs (like psychoactive drugs can still diffuse through)
Depot binding
- drug affects peak and duration of drug concentration
- Drug remains in system in inactive state, so it is protected from metabolism
first order kinetics
drugs cleared at exponential rate based on half life
zero-order kinetics
drugs cleared at (constant) linear rate because metabolism/excretion processes are saturated
ex: alcohol
The law of mass action
- More drug molecules = increased receptor occupancy.
- Maximum drug effect = when all receptors are occupied
- The cellular response is proportional to the degree of receptor occupancy.
- Relationship is described by the dose-response curve
ED50 vs ED100
ED50: Dose that produces half the maximum effect
ED100: Effective dose that gives maximum response; adding more drug does not increase the observed drug effect because all receptors are occupied
TD50 vs LD50
TD50: dose that produces a given toxic effect in 50% of subjects
LD50: dose that kills 50% of subjects (lethal dose)
Therapeutic Index
aka margin of safety
= LD50/ED50