NPP: pharmacology

pharmacology

action of drugs in the body

neuropharamcology

study of drug actions in nervous system

psychopharamcology

emphasizes drug actions on mood, mind, thinking, and behavior.

drug action

molecular change produced by a drug when it binds to a target site, such as receptors in membranes.

therapeutic effects

the drug-receptor interaction produces desired physical or behavioral changes. All other effects are side effects.

specific drug effects

based on the physical and biochemical interactions of a drug with a target site in the living tissue.

nonspecific drug effects

They are based on certain unique characteristics of the individuals, such as mood, expectations, perceptions, and attitudes.

placebo effect

a nonspecific psychological effect due to mind-body interactions. Some explanations for it include conscious expectation of outcomes, social learning, and Pavlovian conditioning.

Principles of ADME

• absorption: how will it get in?

• metabolism: how is it broken down

• distribution: where will it go

• excretion: excretion

bioavailability

amount of drug in blood that is free to bind at targets.

drug administration

inhalation, intravenous, intramuscular, intraperitoneal, and subcutaneous.

cerebrospinal fluid (CSF)

fluid that fills the subarachnoid space around the brain and spinal cord, ventricles, and canals.

blood brain barrier (BBB)

the separation between brain capillaries and the brain/CSF

how are drugs eliminated?

metabolism (biotransformation), where metabolites are excreted. drug clearance from the blood is usually expontential (first-order kinetics) and so drugs are eliminated at a constant rate (zero-order kinetics)

half-life

amount of time required for the removal of 50% of the drug. It determines the interval between doses.

affinity

efficacy

what does neuropharmacology identify?

drugs that act or mimic the action of neurotransmitters to enhance or reduce normal functioning of brain cells.

where do most hormones that act on the brain bind to and what does that hormone binding do?

They bind to receptors in the cytoplasm or cell nucleus. They can alter cell function by triggering changes in gene expression.

Receptor agonist

has the best chemical “fit” (highest affinity); attaches readily to the receptor and produces significant biological effect.

receptor antagonist

also fits receptors but produces no cellular effect (low efficacy).

antagonist

prevents active ligands from binding to the receptor

partial agonists

ligands that bind to the agonist recognition site but trigger a response that is lower than that of a full agonist at the receptor.

inverse agonists

initiate a biological action that is opposite to that produced by an agonist, and also antagonize the effects of other agonists.

competitive antagonists

drugs that compete with agonists to bind receptors but do not initiate intracellular effects, reducing the effect of the agonist.

noncompetitive antagonists

They reduce the effect of agonists by binding to the receptor at a site other than the agonist binding site, disturbing the cell membrane supporting the receptor, and interfering with cell processes that were initiated by the agonist.

What ways can drugs act as agonists in the brain?

enhancing synaptic function by increasing neurotransmitter synthesis. or release and prolonging action of the neurotransmitter within the synapse.

upregulation

The number of receptors is increased. It is also a compensatory change after prolonged absence of the drug.

down-regulation

The number of receptors is reduced. It is also a compensatory change after chronic activation of the receptor.

dose-response curves

It describes the extent of the effect (response) produced by a given drug concentration (dose).

threshold dose

smallest dose that produces a measurable effect.

Ed50 (50% effective dose)

dose that produces ½ the maximal effect

ED100 (100% effective dose)

maximum response. it can be assumed that all receptors are occupied. further increase in dose does not produce a better response.

ED 50 0f different drugs from most to least potent

Hydromorphone → morphine → codeine → aspring