Lecture 6: Psychopharmacology Flashcards
non-medicinal drug
can be defined as something, often an illegal substance, that causes addiction
medicinal drugs
substances that can be recognized by an official pharmacopeia
- intended for the treatment of diseases
psychoactive drugs
chemical substances that pass through the blood-brain barrier and reach the central nervous system to change something there
pharmaceutical drugs
substances used to diagnose/treat/prevent diseases or affect the structure/function of the body
psychopharmacology
the study that deals with the effect of drugs
class A
these drugs are considered the most harmful
- includes heroin, methadone, crack, ecstasy, magic mushrooms, and crystal meth
class B
these drugs are considered less harmful than class A drugs
- include amphetamines, barbiturates, and dihydrocodeine
- some class B are reclassified to class A when prepared for injection (amphetamines, dihydrocodeine, and codeine)
class C
these drugs are considered the least harmful of the controlled drugs
- bezodiazepines and steroids
pharmacokinetics
deals with the factors that influence a drug
- what the body does with the drug
- route of administration, rate of absorption, termination of drug action, and elimination of the drug are important
pharmacodynamics
what the drug does to the body
oral (PO) route of administration
through the mouth
- the drug must be lipid-soluble
- rate of absorption influenced by the contents of the stomach
rectal (PR) route of administration
administered into the rectum
- route is irregular, unpredictable, and incomplete
aerosol route of administration
inhaled through the lungs
- allow for rapid delivery of the drug molecules to the brain
transdermal (TD) route of administration
through the skin
transmucosal (TM) route of administration
administration through the mucous membranes
- intranasally (nose)
- sublingually (under tongue)
parenteral route of administration
does not go through the gastrointestinal system
intravenous route of administration
when a drug is delivered directly to the bloodstream and therefore reaches the brain very quickly
subcutaneous (SC) route of administration
when the drug is delivered just under the skin
- slow and depends on the blood supply to the area of injection
intreperitoneal (IP) route of administration
the drug is delivered through the abdominal wall into the abdominal cavity (peritoneal cavity)
intramuscular (IM) route of administration
the drug is administered into the muscle
intrathecal route of administration
the drug is injected into the subarachnoid space in the spinal canal, reaching the cerebrospinal fluid
intracerebroventricular (ICV) route of administration
the drug is delivered to the ventricles of the brain
- performed in animals
epidural route of administration
the drug is delivered to the epidural space
distribution of ingested drugs
the stomach and intestines must actively absorb it
- first passes through the blood vessels to the liver
- there is a separate blood vessel system that first passes through the liver and only then to the rest of the body
- the liver can transform the drug and therefore a smaller percentage can be measured in the blood than was initially taken
cell membrane
the drug must pass through the phospholipid cell membrane to enter the cell
- fat-soluble drugs can easily pass through the cell membrane, but many drugs are not fat-soluble
walls of the capillaries
to enter the cell, the drug must leave the capillaries
- thin and formed by a single layer of cells
- between the cells are small holes that allow the exchange of small molecules
blood-brain barrier
has 2 major components, capillaries and glial cells
- in the brain, capillaries are tightly packed together and covered by a glial sheath made by astrocytes
- all psychoactive drugs can cross the blood-brain barrier
placental barrier
the placenta connects the mother to the fetus
- the point where drugs that the mother has taken can be passed on to the unborn child
- drugs crossing this barrier can have devastating effects on the development of the fetus
exit routes of drugs
- kidneys (most common)
- lungs
- bile
- skin
two phases of biotransformation (hepatic metabolism)
phase 1: involves the oxidation of the drug
- the liver converts it into a compound that is less fat-soluble and also less active
phase 2: involves the combination (conjugation) of the drug and a small molecule by the liver
- small molecules, such as glucuronide that are important in inactivating the drug, produce a metabolite that is highly ionized (slow/passive)
the renal system
processes hydrophilic drugs and those that have undergone hepatic biotransformation
half-life of drugs
the time it takes for the drug concentration to drop by 50% and then by 50% again
- first half-life, then second half-life