Psychopharmacology by Sue Henderson

Terminology Psychoactive or Psychotropic Psycho- pharmacotherapy Recreational use

National Health Survey 04-05

Decline in hospital stay

Sedative Hypnotic Sleepers “downers” Anti-psychotics Neuroleptics Major tranquillizers Anti- depressants (mood elevators) Anti-anxiety Anxiolytics Minor tranquilizers Side Effect drugs Anti-Parkinson (anti-cholinergic) Mood stabilizers (Anti-manic) CNS stimulants “uppers” Beta Blockers (propranolol) Anti- convulsants as mood stab

Key points about drugs: Drugs alter or mimic body functions (but do not create new functions) Drugs have multiple actions (which may or may not be desired). Most psychotropic drugs interact with the body via receptors.

Development of a drug 2. “Gee it’s wonderful. It’s simple & cures magically” 1. “Another one of his fool ideas” 4. Used carefully in selected cases it is the best therapy for “X” disease. 3. Death from “X”. “It’s a poison! I wouldn’t give it to a dog!”

Pharmacokinetics (Study of movement of drug through the body) Absorption Distribution Metabolism Elimination

Pharmacokinetics (Study of movement of drug through the body) Absorption: The rate at which a drug gets out of the G.I. tract & into the blood stream. Distribution: process of drug molecules leaving the blood stream to reach tissues & organs.

Body membranes affecting drug distribution: Capillaries General body capillaries allow drug molecules to pass freely into the surrounding tissue.

Blood Brain Barrier BBB Brain capillaries have a dense walled structure & are surrounded by glial cells (lipid). This prevents many drug molecules from entering the surrounding tissue. Glial cells Capillary wall

Termination of drug action. Metabolism: Detoxification or breakdown. Enzymes (Cytochrome P450) in liver cells transform drug from fat soluble to water soluble. Elimination: removal of drug from body. Most via kidney’s, lungs & G.I. Tract (small amounts)

Pharmacodynamics. How drugs act on body Drug receptor interaction: drug concentrated at the site of action. Effect (body responses): Therapeutic effects, intoxication & side effects. The effect will vary depending on age, gender & health of person, plus the route, frequency of use, duration of use and the environment in which the drug is consumed.

Mechanism of action Blockade of receptors Receptor sensitivity changes Reuptake inhibition Interference with storage vesicles Pre-curser chain interference Synaptic enzyme inhibition Second messenger cascade

Dendrite Normal neurotransmission Receptor Neurotransmitter Synapse Presynaptic storage vesicles Re-uptake pump Dendrite Axon

Agonist = Mimic

Agonist = Facilitate binding

Blocking = Antagonist

Up-regulation

Down-regulation

Noradrenaline Dopamine Serotonin Acetylcholine GABA Glutamate All 6 major neurotransmitters have been shown to influence each other’s function in the brain.

Normal Acetylcholine Dopamine Noradrenaline Serotonin =

Depression Noradrenaline & Serotonin Acetylcholine

Mania Acetylcholine Glutamate, Noradrenaline Dopamine

Schizophrenia AcetylcholineDopamine

Parkinson’s Dopamine Acetylcholine

Dementia Acetylcholine Dopamine Norepinephrine Serotonin

References Bryant, B. J., Knights, K. M., & Salerno, E. (2002). Pharmacology for health professionals. Marrickville, N.S.W.: Elsevier Science Harcourt Australia. Glod, C. A. (1998). Contemporary psychiatric-mental health nursing : the brain-behavior connection. Philadelphia: F.A. Davis.

References Julien, R. M. (2001). A primer of drug action : a concise, non-technical guide to the actions, uses, and side effects of psychoactive drugs. New York: W. H. Freeman and Co. Salerno, E. (1999). Pharmacology for health professionals. St. Louis: Mosby. Townsend, M. C. (2000). Psychiatric mental health nursing: Concepts of care. (3rd ed.). Philadelphia: F. A. Davis.

References Whelan, G. (1998). The pharmacological dimensions of psychoactive drugs. In M. Sabto (Ed.), Drug use in Australia: A harm minimisation approach (pp.14-29). Melbourne: Oxford University Press.