Pharmacology

TEST TAKING TIPS

MECHANICS

What are some basic drug properties?

• Absorption, distribution, metabolism, elimination

What is first-order kinetics?

• Drug dose determines quantity eliminated (dose-dependent elimination)

What is zero-order kinetics?

• Also known as Hoffman elimination: constant drug quantity eliminated per unit time

What is the primary role of the P450 system?

• Primary drug oxidizers

What are some of the inducers of the P450 system?

• Cigarette smoke, phenobarbital, rifampin, ethanol, INH, phenytoin, etc

What are some of the inhibitors of the P450 system?

• Grapefruit, erythromycin, nelfinavir, itraconazole, etc

What is half-life of a drug?

• Purpose of dosing by half-life is to achieve steady-state concentration. Typical drugs reach steady state after 5 half-lives

What is a Phase I reaction?

• Nonsynthetic reaction, for example, oxidation/reduction, NOT conjugation

What is a Phase II reaction?

• Synthetic reaction, for example, conjugation, methylation, sulfation, etc

GASTROINTESTINAL

ESOPHAGUS

What are some treatments for achalasia?

• Calcium channel blockers, long-acting nitrates, botulinum toxin injections

What is the management for esophageal varices bleeding?

• Vasopressin (splanchnic vasoconstrictor at V1 receptors, increases factor VIII and VWF via extrarenal V2 receptors). Propanolol/Nadolol (preventative role; inhibits B2 adrenergic splanchnic vasodilation). Nitrates (reduce portal venous pressure)

What are some treatment options for reflux disease?

• Selective H₂ blockers (cimetidine, ranitidine, etc) = 24-hour acid reduction by 70%.

• Proton pump inhibitors (pantoprazole, omeprazole, etc) = 10% rebound hyperacidity after discontinuing due to hypergastrinemia

STOMACH

What are the D₂ agonists motility agents and how do they work?

• Domperidone and metoclopramide, they increase lower esophageal sphincter (LES) tone, increase antrum contraction, increase small bowel peristalsis (beware of extrapyramidal symptoms ...