Principles of Drug Action (BIO 365) Test #1
September 25, 2009 Each of the 15 multiple choice questions is worth 0.8 marks out of 30.
1. The drug diphenhydramine is marketed as Benadryl by the pharmaceutical company McNeil-PPC and as Nytol by
Pharmacological principles of chemical teratogenesis Placental transfer. The placenta is not a barrier completely protecting the fetus from external chemicals; instead it acts as a type of sieve, allowing small chemicals (<600 Da) and excluding only those
Dependence of drug absorption on pH and drug protonation
Almost all drugs can be classified as: (1) uncharged molecules; (2) organic acids; or (3) organic amines. For example, an amine type of drug can take two forms as shown to the right; protonation dec
Liver: Functions 1. Detoxification of drugs and toxins 2. Formation of bile (required for absorption of fats and fatsoluble vitamins)
3. Manufacture of plasma proteins (albumin & blood
4. Urea formation (from ammonia and CO )
Protein binding and pharmacological actions
Only free drug (unbound) can reach its sites of action to exert a pharmacological effect.
Binding to plasma proteins decreases the maximum intensity of action of a single dose of a drug because it lowers peak fr
A review of fate of drugs in the body.
The quantitative description of the rates of the various steps of drug disposition, including: 1. absorption of drugs 2. distribution to organs and tissues 3. elimination by biotransformation and exc
Thus far we have been assuming that the rates of various processes (distribution & elimination) are proportional to the drug concentration in the compartment from which drug molecules exit. This is a valid assumption for processes controlled by diffusion
Since an immediate effect is desired, a loading dose (L) of the drug is rapidly administered to fill body stores and establish Cther.
Example: Assumethe amount of to give a drug to a 70 kg= L and that At steady state we are about drug in the body is VC
Specificity of drug action
No drug is entirely specific in the sense that it acts exclusively only on one type of cell or tissue, having just the desired effect and no other.
Drugs vary in their specificities and the usefulness of a drug clinically is oft
Key Concepts: I. Neuronal Membrane Potential II. Action Potentials and how they are generated III. Neurotransmitters IV. Metabotrophic vs Ionotropic Receptors V. Properties of Ionotropic Receptors VI. Cys-loop vs Glutamate Receptors VII. Single Channel Pr
Referringbacktothelastlecture,welearnedthattherewere twomajorclassesofneurotransmitterreceptors,ionotropic receptorsand. The second major type of neurotransmitter receptor MetabotropicNeurotransmitterbindingcausesa conformationalchangeinthereceptorwhichle
Pharmacogenetics is the study of the influence of heredity on the responses to drugs, or their fates in the body. When administering a drug, a physician would like to be able to predict, explain and control variability in the responses of
Sources of variation in drug responses
Dosing amounts and schedules are determined empirically, based on extensive clinical observations. These doses are those that have therapeutic efficacy in most patients on most occasions, and produce the desired ther
Adverse Drug Reactions
All drugs have the potential to produce deleterious consequences. Even Hippocrates (400 BC) was aware of this: Above all, do no harm. Voltaire didnt have a very high opinion of physicians stating They poured drugs of which they knew
Toxicology is the study of the adverse effects of chemical agents on biological systems. A number of classifications can be used to subdivide the general field of toxicology.
Toxic agents themselves may be classified according to: (1) the poten
Principles of Drug Action (BIO 365D)
Dr. John Mihic Section of Neurobiology MBB 1.148 [email protected] Office hours: Mondays & Fridays 7:30-10 AM Course notes, syllabus, and tests from previous years can be found on the course website on Blackboard
Drug Solubility and Absorption
Goal of drug administration: get an adequate (but not toxic) concentration of drug to the necessary site of action as quickly as possible and to maintain that concentration as continuously and evenly as possible. Route of dr
Behavioural Pharmacology Behavioural pharmacology is the study of changes in behaviour produced by a drug, and the mechanisms by which the drug produces these changes. Ultimately we are concerned by the behavioural effects of drugs in humans, but we perfo
Behavioural Pharmacology II
Effects of drugs on behaviour controlled by schedules of reinforcement
To determine the effects of a drug on behaviour one first obtains a pre-drug (placebo) baseline of an animals performance of a measurable task and then test
Behavioural Pharmacology III Behavioural models of mental disorders Animal models of human disorders are useful in the development of new drugs for those disorders. A. Models for Anxiety 1. Elevated plus maze
An elevated plus maze is a cross-shaped (t-sha
Drug abuse and dependence No agreement has been reached on the exact definition of the word addiction. The pattern of behaviour leading to the excessive use of psychoactive substances is generally referred to as drug dependence.
Drug dependence can be def
Tolerance to drugs
There are two forms of tolerance to drugs:
1. Metabolic (pharmacokinetic) 2. Functional (pharmacodynamic)
After the chronic administration of many drugs, tolerance can be seen to develop. This means that higher doses of the drugs may ne
Drugs of abuse: pot, speed, crack, acid and XTC
The hemp plant (Cannabis sativa) produces a number of chemically related compounds of which 1- 9-tetrahydrocannabinol is the primary active ingredient. The dried leaf material is marijuana (or grass
Alcohol & evolution? Alcohol use dates back to prehistoric times & distillation was
invented by the Arabs, from whom it spread to Europe in the Middle Ages. tandard contains g of alcohol: bA s(4-5% EtOH)drink glass of wineabout 13.61.5 oz (43 ml)
General characteristics of general anaesthesia Reversible
Failure to respond to a noxious stimulus Blockage of cardiovascular, g.i. and respiratory reflexes Amnesia Loss of consciousness
Desirable actions of general anaesthetics
Characteristics of psychosis
1. Delusions; fixed false beliefs. Eg., The government is monitoring my brain waves. 2. Hallucinations - the experience of perceptual sensations in the absence of stimulation. These may be visual or aural (eg.,
Antidepressants and mood stabilizers
Antidepressants are used to treat affective disorders 1. Major depression 2. Bipolar disorder (manic depressive) Diagnosis
1. Must have depression for at least 2 weeks (or mania for 1). 2. Signs include depressed mood,
The first clinically useful antibiotic was penicillin, discovered by Fleming in 1928 (from the penicillium mold). Much work has been done in structurally modifying the natural antibiotics and most antibiotics in current use are semisynthetic.
A diverse group of organic compounds that either cannot be synthesized at all by the body, or synthesized in sufficient amounts to maintain normal tissue function. Thirteen vitamins have been identified in humans.
Vitamins are categorized as eith
Despite relatively recent identification of antiviral medications the primary approach to controlling virus is prevention (eg. vaccinations, prophylactic treatment of susceptible people). Antiviral medication development has been slow because v