Class Notes (810,860)
Canada (494,337)
PHAR 100 (172)
Bill Racz (60)

Lesson A.3 Notes.docx

5 Pages
Unlock Document

Queen's University
Pharmacology and Toxicology
PHAR 100
Bill Racz

Lesson A. 3 - Dose-Response Curves & Selective Toxicity Potency and Efficacy of Drugs • Potency – refers only to amount of drug that must be given to obtain a particular response o Ex. “Drug A is more potent than Drug B” means that one needs to take less of Drug A to achieve the same effect that is obtained from Drug B o term tells us what the maximum effect is that is obtainable with a given drug • Efficacy - the maximum effect is that is obtainable with a given drug o Ex. morphine has greater efficacy that aspirin in the relief of pain. Aspirin is only effective in relieving mild to moderate pain, while morphine is able to relieve pain of nearly all intensities o efficacy of a drug is a more important characteristic than the potency. Selective Toxicity • injury of one kind of living matter without harming some other kind o ex. pesticides kill weeds, fungi and pests without harming plant growth • selective toxicology by accumulation - have an agent which will be selectively accumulated by the species to be destroyed o ex. 10% Sulphuric acid weed spray will accumulate on weeds due to their rough and waxy leaves, while exterior of cereal grass is smooth and waxy, meaning acid will not accumulate and kill it o anticancer drugs are used to treat cancer, as sensitive cancer cells accumulate the anticancer drugs and are killed. Some cancerous cells are resistant to these drugs (multidrug resistance proteins) by extruding these drugs.  P-glycoprotein – identified by Dr. Victor Ling in Toronto in 1976  MRP - Dr. Susan Cole and Dr. Roger Deeley in 1992, at Queen’s University Chemotherapy – An Example of Selective Toxicity • the use of drugs to injure an invading organism without injury to the host • term coined by Paul Ehrlich • demonstration that diseases of many types are caused by microbes was made by Pasteur and Koch in the 19th century Lesson A. 3 - Dose-Response Curves & Selective Toxicity • Paul Ehrlich, the father of chemotherapy was born in Germany in 1854 o most workers at his time thought it was not possible to have a substance that would only kill microbes and not harm the individual whose body the bacterial were living o they also thought that drugs only worked by stimulating the body’s defence system o through the idea of staining, he came up with the idea of attaching a toxic group to the chemical that would specifically kill the parasite o “bodies do not act unless fixed” o There are four requirements for success – “money, patience, cleverness and luck o Treated syphilis by using arsenic as his toxic grouping Sulfonamides • in 1935, Domagk studied the effects of a large number of chemical compounds against a bacterium known as streptococcus in mice • injected numerous chemicals into mice together with streptococcus to see if any of these drugs could save the mice from the action of this bacterium o Prontosil was discovered, which would harm the streptococcus, but not the mouse o 1932-1935 71% patients with streptococcus in blood died vs. 1935, very few died from it o Found inactive in a test tube, because it is split in the liver to give sulfanilamide which is the active principle  Both microbes and host cells use folic for growth  Unable to enter microbes, so they must have a device for making folic acid themselves  do so by taking up compound PABA, which is manufactured to make folic acid  Sulfanilamide closely resembles PABA in structure, and microbe cannot distinguish between them, so Sulfanilamide blocks PABA and folic acid is
More Less

Related notes for PHAR 100

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.