Adverse Drug Reactions and Drug Interactions

This lecture by Dr. Bruce Clayton occurred on Friday, August 28th. return to the RX 413 Class page

Study Materials
Required Reading Dr. Clayton's lecture on Adverse Drug Reactions and Drug Interactions
 * Link to PPT
 * Link to Handout
 * Link to Panopto

Suggested Reading

 * Tsouronis, C; Adverse Drug Reactions and Drug-Induced Diseases, In Helms, RA and Quan, DJ, eds. Textbook of Therapeutics, Drug and Disease Management, 8th ed., Lippincott, Williams and Wilkins, Philadelphia, 2006: 31-44
 * Middleton, RK; Drug Interactions. In Helms, RA and Quan, DJ, eds. Textbook of Therapeutics, Drug and Disease Management, 8th ed., Lippincott, Williams and Wilkins, Philadelphia, 2006: 47-68

Define “adverse drug reaction” according to the Rawlins and Thompson Classification and the ASHP definition of a significant event.

 * Rawlins and Thompson Classification:


 * Type A = Predictable (e.g. a side effect—a dose-related, predictable reaction to a drug) particularly likely to occur with narrow therapeutic index drugs: (e.g. bleeding from warfarin; hypoglycemia from sulfonylureas.)


 * Type B = Unpredictable; not to be expected from the known pharmacological action of a drug when given in the usual therapeutic doses to a patient whose body handles the drug in the normal way (e.g., malignant hyperthermia during anesthesia; immune (allergy) reactions; teratogenicity; carcinogenicity).


 * ASHP definition of a significant events


 * any unexpected, unintended, undesired, or excessive response to a drug that:
 * 1. Requires discontinuing the drug (therapeutic or diagnostic)


 * 2. Requires changing the drug therapy


 * 3. Requires modifying the dose (except for minor dosage adjustments)


 * 4. Necessitates admission to a hospital


 * 5. Prolongs stay in a health care facility


 * 6. Necessitates supportive treatment


 * 7. Significantly complicates diagnosis


 * 8. Negatively affects prognosis, or


 * 9. Results in temporary or permanent harm, disability, or death

List & define predictable and unpredictable causes of non-immunologic drug reactions.
Predictable (non-immunologic)
 * pharmacological side effect - dry mouth from antihistamines
 * secondary pharmacological - diarrhea from taking antibiotics
 * drug toxicity - rhabdomyolysis from taking statins

Describe the role of the pharmacist in preventing adverse drug reactions and drug interactions.
return to the RX 413 Class page