Pharm 1: high yield green topics

What type of tissue is targeted in subcutaneous (SC) drug administration?

Poorly vascularized adipose tissue

What type of drugs are best suited for subcutaneous (SC) administration?

Oil-based drugs

Why does subcutaneous (SC) administration have a slow onset?

Due to poor vascularization of adipose tissue

What volume limitation is associated with subcutaneous (SC) administration?

Only small volumes can be administered

What is the first-pass effect?

Reduction of bioavailability (F) of an oral drug due to metabolism before reaching systemic circulation

How does the first-pass effect impact oral drug bioavailability?

It decreases bioavailability

What is one strategy to avoid the first-pass effect?

Use an alternate route of administration

What is another strategy to bypass the first-pass effect?

Design a prodrug

What patient population is at risk for gray baby syndrome?

Newborns and children under age 2

Why does chloramphenicol cause toxicity in gray baby syndrome?

Increased chloramphenicol levels leading to mitochondrial toxicity

What enzyme deficiency contributes to gray baby syndrome?

Immature UDP-glucuronosyltransferase (UGT) activity

What is a key symptom of gray baby syndrome?

Vomiting

What is a key neuromuscular symptom of gray baby syndrome?

Flaccidity

What temperature-related symptom occurs in gray baby syndrome?

Hypothermia

What respiratory complication is seen in gray baby syndrome?

Respiratory distress

What acid-base disturbance occurs in gray baby syndrome?

Metabolic acidosis

What is the primary detoxification pathway for the toxic acetaminophen metabolite (NAPQI)?

Glutathione conjugation

Why can acetaminophen toxicity occur despite normal metabolism?

Finite amount of glutathione (rate-limiting)

Why are alcoholics more susceptible to acetaminophen toxicity?

Chronic alcohol use induces CYP2E1, increasing NAPQI formation

What is the mechanism of action of N-acetylcysteine (NAC) in acetaminophen toxicity?

Provides SH group to bind toxic metabolite (NAPQI) and form cysteine conjugates for excretion

How does N-acetylcysteine (NAC) affect glutathione levels?

Restores glutathione activity

How can diet affect drug metabolism?

By inducing or inhibiting CYP450 enzymes

What is the effect of grapefruit juice on CYP3A4?

Inhibits CYP3A4

What is the effect of St. John's wort on CYP3A4?

Induces CYP3A4

What is the effect of cigarette smoke (polycyclic aromatic hydrocarbons) on CYP enzymes?

Induces CYP1A1, CYP1A2, and CYP2E1

What is enzyme induction in drug metabolism?

Increased CYP enzyme activity leading to increased metabolism

What is the effect of enzyme induction on drug levels?

Decreases drug levels due to increased metabolism

Which drugs are classic CYP inducers?

Rifampin, phenytoin, barbiturates

Which CYP enzymes are induced by rifampin, phenytoin, and barbiturates?

CYP3A4, CYP2C9, CYP2C19

What is the effect of enzyme induction on warfarin levels?

Decreased warfarin effect → may require higher dose

What is enzyme inhibition in drug metabolism?

Decreased CYP enzyme activity leading to decreased metabolism

What is the effect of enzyme inhibition on drug levels?

Increases drug levels due to decreased metabolism

Which drugs are classic CYP inhibitors?

Cimetidine, erythromycin, ketoconazole

Which CYP enzymes are inhibited by cimetidine, erythromycin, and ketoconazole?

CYP3A4, CYP2C9, CYP2C19, CYP1A2

What is the effect of enzyme inhibition on warfarin dosing?

Increased warfarin effect → requires lower dose

What is the formula for half-life (t½) in pharmacokinetics?

t½ = (0.693 × Vd) / Clearance

What happens to half-life with aging?

Decreased half-life due to decreased muscle mass and Vd

How does obesity affect half-life?

Increases half-life due to increased adipose tissue and Vd

How does increased metabolism affect half-life?

Decreases half-life due to increased clearance

How does decreased metabolism affect half-life?

Increases half-life due to decreased clearance