Pharmacology One-Liners

Half-life (T1/2)

Time required to reduce amount of drug in the body by half during elimination, constant in first order kinetics (majority of drugs)

Volume of distribution (Vd)

Relates the amount of drug in the body to the plasma concentration

Cp

Plasma concentration of a drug at a given time

Clearance (CL)

The ratio of the rate of elimination of a drug to its plasma concentration

First pass effect

Hepatic metabolism of the drug before it reaches the systemic circulation

Bioavailability (F)

The fraction of unchanged drug that reaches systemic circulation after administration

Steady state

When the rate of drug input equals the rate of drug elimination

Oxidation, reduction, hydrolysis

Different steps of Phase I

First order kinetics

Constant FRACTION of drug eliminated per unit time

Zero order kinetics

Constant amount of drug eliminated per unit time

Loading dose

A higher initial dose given to rapidly achieve effective blood levels (Cp(Vd/F))

Maintenance dose

Amount of drug required to keep a desired mean steady-state concentration in the body (Cp(CL/F))

Affinity

Ability of a drug to bind to a receptor

Specificity

Selectivity of a drug for its receptor

Potency

Amount of drug necessary to elicit a biologic effect compared with another drug

Efficacy

Ability of drug to produce the maximal effect

Full agonist

Ability of a drug to produce maximal response after binding to the receptor

Partial agonist

Ability to produce less than maximal response after binding to the receptor

Competitive antagonist

Ability to bind reversibly to the active site without activating the effector system

Noncompetitive antagonist

Ability to bind irreversibly to the active site or bind to an allosteric site without activating the effector system

Acetylcholine

Mechanism of action utilizes ligand-gated ion channels

ED50

Dose that produces therapeutic response in 50% of the population

TD50

Dose that is toxic to 50% of the population

LD50

Dose that is lethal to 50% of a population of animals

Therapeutic index

Window between therapeutic effect and toxic effect

High therapeutic index

Drugs that have a large margin of safety

Low therapeutic index

Drugs that have a narrow margin of safety

Antidote for anticholinergic poisoning

Physostigmine

Antidote for organophosphate/anticholinesterase poisoning

Atropine

Antidote for iron salt poisoning

Deferoxamine

Antidote for acetaminophen poisoning

N-acetylcysteine

Antidote for arsenic, mercury, and gold poisoning (AMG)

Dimercaprol

Antidote for Wilson's disease (copper poisoning)

Penicillamine

Antidote for heparin toxicity

Protamine sulfate

Antidote for warfarin toxicity

Vitamin K1 and fresh frozen plasma

Antidote for tissue plasminogen activator (t-PA), streptokinase

Aminocaproic acid

Antidote for methanol and ethylene glycol toxicity

Fomepizole

Antidote for opioid toxicity

Naloxone (IV)

Antidote for benzodiazepine toxicity

Flumazenil

Antidote for tricyclic antidepressants (TCA)

Sodium bicarbonate (alkalinize plasma)

Antidote for carbon monoxide poisoning

100% O2 and hyperbaric O2

Antidote for digitalis toxicity

Anti-dig Fab fragments

Antidote for methotrexate toxicity

Leucovorin

Antidote for beta-blocker overdose

Glucagon

Method to reduce salicylate intoxication

Sodium bicarbonate (alkalinize urine), dialysis

Inducer of CYP50

phenobarbital

Inducer of CYP50

carbamazepine

Inducer of CYP50

phenytoin

Inducer of CYP50

St. Johns wort

Inducer of CYP450

Rifampin

Inhibitor of CYP450

ketoconazole (azoles)

Inhibitor of CYP450

ritonavir

Inhibitor of CYP450

cimetidine

Inhibitor of CYP450

grapefruit juice

Inhibitor of CYP450

quinidine

Inhibitor of CYP450

amiodarone

Phase II conjugation reaction

Glucuronidation

Phase II conjugation reaction

acetylation

Phase II conjugation reaction

glutathione conjugation

Phase II conjugation reaction

sulfation

Phase II conjugation reaction

methylation

Steroid

Mechanism of action utilizes intracellular receptors

Hormones

Mechanism of action utilizes intracellular receptors

Insulin

Mechanism of action utilizes transmembrane receptors with intrinsic enzymatic activity

EGF

Mechanism of action utilizes transmembrane receptors with intrinsic enzymatic activity

TGF beta

Mechanism of action utilizes transmembrane receptors with intrinsic enzymatic activity

PDGF

Mechanism of action utilizes transmembrane receptors with intrinsic enzymatic activity

BNP

Mechanism of action utilizes transmembrane receptors with intrinsic enzymatic activity

Nicotine

Mechanism of action utilizes ligand-gated ion channels

Antidote for lead poisoning

EDTA

Antidote for lead poisoning

succimer

Antidote for lead poisoning

dimercaprol

Antidote for lead poisoning

penicillamine

Antidote for cyanide poisoning

Nitrites

Antidote for cyanide poisoning

thiosulfate

Antidote for cyanide poisoning

hydroxocobalamin

Antidote for organophosphate/anticholinesterase poisoning

pralidoxime (2-PAM)

Antidote for arsenic, mercury, and gold poisoning (AMG)

succimer

Antidote for methanol and ethylene glycol toxicity

ethanol