Tox Exam 1 Q&A

What is toxicology?

The study of adverse effects of chemical, physical, or biological agents on living organisms

What is pharmacology?

The study of drugs, including their uses, effects, and mechanisms of action

What is a toxin?

A toxic substance produced by a biological organism

What is a toxicant?

A toxic substance produced by human activity or as a byproduct

What is a poison?

Any substance that can harm a biological system

What is pharmacokinetics?

The study of how a drug moves through the body (ADME)

What does ADME stand for?

Absorption, Distribution, Metabolism, Excretion

What is pharmacodynamics?

The study of how drugs affect the body

Who is the father of toxicology?

Paracelsus

What is the FDA definition of a drug?

A substance used in diagnosis, cure, mitigation, treatment, or prevention of disease

What did the 1906 Pure Food and Drug Act do?

Required labeling of dangerous ingredients in food and drugs

What did the 1938 FD&C Act require?

Proof of drug safety before marketing

What did the 1962 Kefauver-Harris Amendment require?

Proof of drug safety AND efficacy

What did the 1970 Controlled Substances Act establish?

Drug schedules based on abuse potential

What did the 1994 DSHEA do?

Allowed supplements to be sold without prior FDA approval

What is a Schedule I drug?

No accepted medical use and high abuse potential

What is a Schedule II drug?

Accepted medical use with high abuse potential

What is a Schedule III drug?

Moderate abuse potential

What is a Schedule IV drug?

Low abuse potential

What is a Schedule V drug?

Lowest abuse potential

What agency regulates drugs and food?

FDA

What agency regulates controlled substances?

DEA

What agency regulates food safety and agriculture?

USDA

What agency regulates environmental chemicals?

EPA

What agency regulates workplace safety?

OSHA

What is a therapeutic effect?

The intended beneficial effect of a drug

What is an indication?

The condition a drug is used to treat

What is a contraindication?

A situation where a drug should not be used

What is a side effect?

An unintended effect of a drug

What is an adverse effect?

A harmful or negative side effect

What is a toxic effect?

A harmful effect that results in poisoning

What is a drug agonist?

A drug that activates a receptor to produce a response

What is a drug antagonist?

A drug that blocks a receptor and prevents a response

What is competitive antagonism?

When agonists and antagonists compete for the same receptor

What determines the strength of a drug’s action?

Dose and frequency

What is the minimum dose?

The smallest amount that produces a therapeutic effect

What is a loading dose?

A high initial dose to quickly reach therapeutic levels

What is a therapeutic dose?

The dose that produces the desired effect

What is the maximum dose?

The highest dose that does not cause toxicity

What is a maintenance dose?

The dose used to maintain steady drug levels

What is a toxic dose?

The amount that produces harmful effects

What is ED50?

The dose that produces 50% of the maximum effect

What is LD50?

The dose that kills 50% of test subjects

What is the therapeutic index (TI)?

The ratio of LD50 to ED50

What does a high therapeutic index indicate?

A safer drug

What is half-life?

The time it takes for a drug concentration to decrease by 50%

What is NOAEL?

The highest dose with no observed adverse effects

What is LOAEL?

The lowest dose where adverse effects are observed

Which organs are most exposed to drugs?

Liver, kidneys, brain, cardiovascular system

Which organs are most susceptible to toxicity?

Liver, kidneys, lungs

What is a teratogen?

A substance that causes birth defects

What is a carcinogen?

A substance that causes cancer

What is an idiosyncratic reaction?

An unexpected or unusual response to a drug

What is tolerance?

A decreased response requiring higher doses

What is a paradoxical effect?

A response opposite of what is expected

What is dependence?

A physical or psychological need for a drug

When is the critical period for teratogens?

Days 18–55 of pregnancy

What is hypersensitivity?

A mild allergic reaction

What is anaphylaxis?

A severe, life-threatening allergic reaction

What lab values indicate liver damage?

Increased AST, ALT, bilirubin and decreased albumin

What lab values indicate kidney damage?

Increased BUN and creatinine

What indicates lung damage?

Decreased FEV

What adverse effect is associated with NSAIDs?

Tinnitus

What is the mechanism of aspirin?

Inhibits COX and prostaglandin synthesis

What is the antidote for acetaminophen overdose?

N-acetylcysteine (NAC)

What is mutagenesis?

Damage to DNA

What is clastogenesis?

Damage to chromosomes

What is aneuploidy?

Abnormal number of chromosomes

What form of a drug is best absorbed?

Unionized form

Where are acidic drugs absorbed?

In acidic environments

Where are basic drugs absorbed?

In alkaline environments

How do you increase excretion of acidic drugs?

Alkalinize urine (sodium bicarbonate)

How do you increase excretion of basic drugs?

Acidify urine (vitamin C or ammonium chloride)

How does food affect drug absorption?

It slows absorption

What is the fastest drug formulation?

Liquid, lipid-soluble drugs

What is the slowest drug formulation?

Enteric-coated tablets

What is the most common route of administration?

Oral

Where does most drug absorption occur?

Small intestine

What is typical oral bioavailability?

20–40%

What is plasma protein binding?

Drugs binding to proteins in blood

Which drug form is active?

Free (unbound) drug

What type of drugs cross the blood-brain barrier easily?

Lipid-soluble drugs

What is metabolism also called?

Biotransformation or detoxification

What happens in Phase I metabolism?

Oxidation, reduction, or hydrolysis via CYP450

What happens in Phase II metabolism?

Conjugation to increase water solubility

What is required for cytochrome P450 function?

Iron

What is enzyme induction?

Increased metabolism and decreased drug levels

What is enzyme inhibition?

Decreased metabolism and increased drug levels

What is first-pass metabolism?

Drug metabolism in the liver after oral absorption

What is the main route of drug excretion?

Urine

How does aging affect drug excretion?

It decreases renal clearance

What is polypharmacy?

Use of 5 or more medications

What does St. John’s Wort do?

Induces CYP450 and decreases drug levels

What does grapefruit juice do?

Inhibits CYP enzymes and increases drug levels

What is NNT?

The number of patients needed to treat to benefit one person

What is the most common type of poisoning?

Ingestion

Who is most at risk for poisoning?

Children ages 1–5

What is the most common poison?

Analgesics (especially acetaminophen)

What causes the most deaths?

Opioids

What is the most deadly poison?

Carbon monoxide