Class Notes (809,444)
Canada (493,713)
PHAR 100 (172)


3 Pages
Unlock Document

Queen's University
Pharmacology and Toxicology
PHAR 100
Hisham Elbatarny

Dose Response and Selective Toxicity Potency and Efficacy • potency – refers to the amount of drug that must be given to obtain a particular response • efficacy – refers to the maximal response that can be obtained with the drug → more important Which drug is more potent? → Ais more potent Which drug has greater efficacy? → B has more efficacy Addingup Dose Response frequency dist = log • as dose increases so does the response dose curve ◦ variability in the response between individuals ◦ variability between drugs. • therapeutic dose must be less than the toxic dose ◦ ex: chemotherapy – toxicity at therapeutic doses Therapeutic Index TD50/ED50 • the higher the number the lower the probability that the drug will cause an adverse effect. • chose 50% where curve is change quickly and linearly • therapeutic window: ~90% response with little adverse effects Selective Toxicity → Harm to one organism w/out harming some other kind. ex: antibiotics, antifungal chemotherapy • need to have insecticides and fungicides • weed killer without harming the crop • kill a parasite without harming the host (human) lice, helminths, bacterial infections, cancer cells • selective accumulation of a herbicide, ex: sulphuric acid. Chemotherapy • early theories of disease suggested that the body was overcome by evil spirits and that treatment was designed to drive off evil spirits, burning of sulphur, blood letting. • Pasteur and Koch demonstrated that certain disease were caused by microbes • this lead to search for new treatments • most scientists were of the opinion that it would be impossible to find agents that are selectively toxic to a micro-organism • Paul Ehrlich did not share this view • he noted that dyes were selectively accumulated by certain tissues • he argued that by designing the correct drug it would bind to parasites selectively • if it bound to parasites but not human cells, human cell would not be injured by the compound. • Eh
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.