PSYCHOPHARMACOLOGY

Psychopharmacology

(from Greek, psȳkhē, "breath, life,

soul"; pharmakon, "drug"; and, -logia “study”)

Psychopharmacology is the study of drug-

induced changes in mood, thinking, and

behavior.

These drugs may originate from natural

sources such as plants and animals, or from

artificial sources such as chemical syntheses in

the laboratory.

Early Psychopharmacology

Hunter-gatherer or surviving tribal cultures

used drugs depends on what the particular

ecosystem a given tribe lives in can support,

and are typically found growing wild.

These societies generally attach spiritual

significance to such drug use, and often

incorporate it into their religious practices.

With the dawn of the Neolithic and the

proliferation of agriculture, new drugs came

into use as a natural by-product of farming.

Among them were opium, cannabis,

and alcohol derived from the fermentation of

cereals and fruits.

Drugs

Drug is “a chemical substance used in the

treatment, cure, prevention, or diagnosis of

disease or used to otherwise enhance physical

or mental well-being”.

Pharmaceutical Drugs

Recreational Drugs

Over-the-Counter Drug

Medicines sold directly to a consumer without

a prescription from a healthcare professional,

as compared to prescription drugs, which may

be sold only to consumers possessing a valid

prescription.

OTC drugs are selected by a regulatory

agency to ensure that they are ingredients that

are safe and effective when used without

a physician's care.

Drugs and its effects

Depressants (Downers) - Chemicals that slow

down the central nervous system and suppress

brain activity causing relief from anxiety.

CANNABIS- make users feel relaxed and

heighten their sensory awareness. Thus, users

may experience a more vivid sense of sight,

smell, taste and hearing.

HALLUCINOGENS- drugs that alter users'

state of consciousness and produce different

kinds of hallucinations. Leads to strong

changes in thought, mood and senses in

addition to feelings of empathy and sociability.

Stimulants (Upper) - act on the central nervous

system and are associated with feelings of

extreme well-being, increased mental and

motor activity.

Cocaine can make users feel exhilarated and

euphoric. Furthermore, users often experience

a temporary increase in alertness and energy

levels, and a postponement of hunger and

fatigue.

ECSTASY- can heighten users' empathy levels

and induce a feeling of closeness to people

around them. It is often used at "rave parties"

to increase participants' sociability and energy

levels.

Opiates & Opioids- Drugs provide pain relief,

euphoria, sedation and in increasing doses

induce coma.

HEROIN-Can make users feel an initial surge

of euphoria, along with a feeling of warmth and

relaxation. Users also often become detached

from emotional or physical distress, pain or

anxiety.

METHAMPHETAMINE- stimulates a feeling of

physical and mental well being, as well as a

surge of euphoria and exhilaration. Users

experience a temporary rise in energy, often

perceived to improve their performance at

manual or intellectual tasks. Users also feel

postponement of hunger and fatigue.

Methadone- is a synthetic opioid that is used

medically as a painkiller and as a substitute for

addiction to narcotics such as heroin.

drowsiness, weakness, nausea, insomnia,

itching, lack of appetite, mood swings, skin

rashes, difficulty urinating, insomnia,

headaches. When taken in larger doses it can

cause slow breathing, irregular heartbeat and

death.

Antipsychotics- class of psychiatric

medication primarily used to manage

psychosis (including delusions, hallucinations,

or disordered thought), in particular

in schizophrenia and bipolar disorder.

Include nausea, emesis, anorexia , anxiety,

agitation, restlessness, and insomnia.

Barbiturates- sedatives prescribed to patients

with sleep disorders and other mental illnesses

to calm them down and put them to sleep.

Constant falling, bruised legs, excessive

nervousness, shaking, sensitivity to noise,

restlessness, sweating, hallucinations and

insomnia.

Benzodiazepine- type of medication known as

tranquilizers or minor tranquilizers, as opposed

to the major tranquilizers used to treat

psychosis.

Changes in appearance and behaviour that

affect relationships and work performance.

Warning signs in teenagers include abrupt

changes in mood or sudden deterioration of

school performance.

Drug Effectiveness

Refers to the ability of a drug to produce a

beneficial effect. A distinction is made between

'method' effectiveness which describes the

effect achievable if the drug was taken as

prescribed and 'use' effectiveness which is the

effect obtained under typical use

circumstances when adherence is not 100%.

Drugs can have more than one effect

The effectiveness of a drug is considered relative to its safety

Drug Literature

It is a document provided along with

a prescription medication to provide additional

information about a drug.

It follows a standard format for every

medication and include the same types of

information.

Drug Literature Format

Clinical pharmacology - tells how the medicine

works in the body, how it is absorbed and

eliminated, and what its effects are likely to be

at various concentrations.

Indications and usage - uses (indications) for

which the drug has been FDA-approved (e.g.

migraines, seizures, high blood pressure).

Contraindications - lists situations in which the

medication should not be used.

Warnings - covers possible serious side

effects that may occur.

Precautions - explains how to use the

medication safely including physical

impairments and drug interactions.

Adverse reactions - lists all side effects

observed in all studies of the drug (as opposed

to just the dangerous side effects which are

separately listed in "Warnings" section)

Drug abuse and Dependence - provides

information regarding whether prolonged use

of the medication can cause physical

dependence

Overdosage - gives the results of

an overdose and provides recommended

action in such cases

Dosage and Administration - gives

recommended dosage(s); may list more than

one for different conditions or different patients

(e.g., lower dosages for children)

How supplied - explains in detail the physical

characteristics of the medication including

color, shape, markings, etc., and storage

information

Site of Action

l. Enzyme Inhibition:

Drugs act within the cell by modifying normal

biochemical reactions. Enzyme inhibition may

be reversible or non reversible; competitive or

non-competitive. Antimetabolites may be used

which mimic natural metabolites. Gene

functions may be suppressed.

2. Drug-Receptor Interaction:

Drugs act on the cell membrane by physical and/or

chemical interactions. This is usually through specific

drug receptor sites known to be located on the

membrane. A receptor is the specific chemical

constituents of the cell with which a drug interacts to

produce its pharmacological effects. Some receptor

sites have been identified with specific parts of proteins

and nucleic acids. In most cases, the chemical nature

of the receptor site remains obscure.

3. Non-specific Interactions:

Drugs act exclusively by physical means

outside of cells. These sites include external

surfaces of skin and gastrointestinal tract.

Drugs also act outside of cell membranes by

chemical interactions. Neutralization of

stomach acid by antacids is a good example.

Drug Interaction with Receptor Site

A neurotransmitter has a specific shape to fit

into a receptor site and cause a

pharmacological response such as a nerve

impulse being sent. The neurotransmitter is

similar to a substrate in an enzyme interaction.

After attachment to a receptor site, a drug may

either initiate a response or prevent a response

from occurring. A drug must be a close "mimic"

of the neurotransmitter.

An agonist is a drug which produces a

stimulation type response. The agonist is a

very close mimic and "fits" with the receptor

site and is thus able to initiate a response.

An antagonist drug interacts with the receptor

site and blocks or depresses the normal

response for that receptor because it only

partially fits the receptor site and can not

produce an effect. However, it does block the

site preventing any other agonist or the normal

neurotransmitter from interacting with the

receptor site.

Alcohol-Placebo Effect

A simulated or otherwise medically ineffectual

treatment for a disease or other medical

condition intended to deceive the recipient.

Sometimes patients given a placebo treatment

will have a perceived or actual improvement in

a medical condition, a phenomenon commonly

called the placebo effect.

Effects of Repeated Administration

Repeated administration of a drug can alter its subsequent effectiveness:

Tolerance: Repeated drug administration results in diminished drug effect (or requires increased dosage to maintain constant effect)

Tolerance can reflect decreased drug-receptor binding or reduced postsynaptic action of the drug

Sensitization: Repeated drug administration

results in heightened drug effectiveness

Withdrawal effects: Abnormal physical or

psychological features that follow the

abrupt discontinuation of a drug that has the

capability of producing physical dependence.

Pharmacokinetics

is the study of drug absorption, distribution

within body, and drug elimination

Absorption depends on the route of administration

Drug distribution depends on how soluble the drug

molecule is in fat (to pass through membranes) and on

the extent to which the drug binds to blood proteins

(albumin)

Drug elimination is accomplished by excretion into

urine and/or by inactivation by enzymes in the liver

Routes of Drug Administration

Intravenous (IV): into a vein (rapid absorption).

A method of introducing a drug into the body

with a hollow needle and a syringe which is

pierced through the skin into the body

Intraperitoneal (IP): into the gut (used in lab

animals). is the injection of a substance into

the peritoneum (body cavity).

Intramuscular (IM): into a muscle.

The injection of a substance directly into

a muscle.

Oral Administration: orally as liquids, capsules,

tablets, or chewable tablets. Oral route is the

most convenient and usually the safest and

least expensive, it is the one most often used.

Sublingual Administration: The dosage form is

placed under the tongue.

Intrarectal Administration: Uses the rectum as

a route of administration for medication and

other fluids, which are absorbed by the

rectum's blood vessels.

Inhalation Administration: via nose. Smoking or

inhalation of a substance is likely the most

rapid way to deliver drugs to the brain, as the

substance travels directly to the brain without

being diluted in the systemic circulation.

Topical Administration: is the application of a

drug directly to the surface of the skin.

Includes administration of drugs to any mucous

membrane

eye – vagina

nose – urethra

ears – colon

lungs

Intracerebral Administration: (into the

cerebrum) direct injection into the brain. Used

in experimental research of chemicals and as a

treatment for malignancies of the brain. The

intracerebral route can also interrupt the blood

brain barrier from holding up against

subsequent routes.[15]

Intracerebroventricular (into the cerebral

ventricles) administration into the ventricular

system of the brain. One use is as a last line of

opioid treatment for terminal cancer patients

with intractable cancer pain.