Drug Toxicity & Teratogenicity

Question 1

A patient presents to clinic with drowsiness and nausea after being prescribed a drug. What type of ADR is the patient displaying?

Answer 1

Mild ADR - the reactions are non-life threatening

Question 2

True/False. Mild ADRs (headaches, nausea, rash) are relatively unpredictable.

Answer 2

True.

Question 3

An embryo is exposed to a teratogen five days following conception. What effect will this have on embryonic development?

Answer 3

If the embryo survives, there will be little effect on development. During the first two weeks after conception, teratogen exposure will damage cells, however, those cells will be replaced by uninjured cells and develop normally.

Question 4

True/False. A drug that displays immunological toxicity in an individual will be toxic in other individuals of the same population.

Answer 4

False. Immunological toxicity is a response by the immune system against the drug. This does not predict toxicity in other individuals.

Question 5

A patient has an allergic reaction to a drug. Their friend recommends continuing taking the drug, but at a lower dose. Will this prevent another reaction?

Answer 5

No. Allergic reactions to drugs is not related to the dose of the drug. Even a small dose will cause a reaction.

Question 6

A fetus is exposed to a teratogen 6 months following conception. What effect will this have on fetal development?

Answer 6

The teratogen may still cause fetal injury, but developmental malformations are less likely. Following the completion of organogenesis in the first trimester, malformations are less likely due to teratogen exposure.

Question 7

True/False. A drug with a high TI is more efficacious.

Answer 7

False. TI tells you nothing about the efficacy of the drug. It can only predict toxicity.

Question 8

Anaphylactic shock following administration of a drug is what type of hypersensitivity?

Answer 8

Type I Hypersensitivity

Question 9

How does drug teratogenicity differ from genotoxicity?

Answer 9

Genotoxicity is damage to the DNA or chromosomes due to a drug. Teratogenicity, however, causes abnormal fetal development, without damaging DNA or chromosomes.

Question 10

What does a small TI indicate about the drug?

Answer 10

A small TI indicates there is a narrow margin for safety. The higher the TI, the greater the margin for safety

Question 11

True/False. A substance that is a teratogen will produce a negative effect in both the mother and fetus.

Answer 11

False. Most teratogens cause abnormal fetal development at a dose that does not affect the mother.

Question 12

How can therapeutic index be calculated?

Answer 12

TI = LD50/ED50

Question 13

A patient is prescribed a drug to treat a chronic disorder. Several weeks later, the patient presents to the ER with acute liver failure due to the drug usage. What type of ADR is the patient displaying?

Answer 13

Toxic ADR - liver failure is life-threatening

Question 14

When is the most sensitive period of fetal development to teratogen exposure?

Answer 14

Third week following conception to the third month of development

Question 15

What is LD50?

Answer 15

The dose required to kill 50% of an experimental animal population

Question 16

What is a phenocopy?

Answer 16

A phenocopy is some physical characteristic that displays genotypic origin, but was actually produced due to environmental exposures/teratogens

Question 17

A drug that causes DNA or chromosomal damage is said to have what type of toxicity?

Answer 17

Genotoxicity

Question 18

Drug disorders that result from physician error are termed…?

Answer 18

Iatrogenic disorders

Question 19

True/False. A single teratogen may cause many developmental malformations in a fetus.

Answer 19

True. Similarly, many different teratogens may cause the same malformations.