Pharmacodynamics and pharmacokinetics

What is the EC₅₀?

The molar concentration of an agonist when it is producing 50% of its maximal possible effect

What are positive and negative allosteric modulators

Allosteric modulators are molecules that bind to a receptor, but not on the main binding site. positive AMs increase agonist effect, negative AMs decrease. They have no effect when there is no agonist

How to calculate therapeutic ratio (aka therapeutic index)

Maximum non-toxic dose/Minimum therapeutic dose

Define bioavailability

The amount of unchanged drug that reaches systemic circulation

What is volume of distribution? V_d

The amount of fluid that would be needed to make a drug evenly distributed in the same concentration as it currently is in in plasma.

V_d = Amount of drug in body/plasma drug concentration

A high volume means the drug is widely distributed in body tissue

A low volume means the drug is mostly in blood/plasma