Drug Reactions

Question 1

what is an adverse drug reaction?

Answer 1

any response to a drug which is noxious, unintended and occurs at doses used in man for prophylaxis, diagnosis or therapy

Question 2

what are the predisposing factors of drug reactions?

Answer 2

age, gender, genetics, sex related, physiological, exogenous, diease-related

Question 3

what is type A drug reaction?

Answer 3

augmented

Question 4

what is type B drug reaction?

Answer 4

bizarre

Question 5

what is type C drug reaction?

Answer 5

chronic

Question 6

what is type D drug reaction?

Answer 6

delayed

Question 7

what is type F drug reaction?

Answer 7

failure of therapy

Question 8

what drug reactions are dose-related?

Answer 8

A, D and F

Question 9

what are the features of type A?

Answer 9

common, related to pharmacological action, predictable, low mortality

Question 10

how do you manage type A?

Answer 10

reduce dose or withhold, consider concomitant therapy

Question 11

what is concomitant therapy?

Answer 11

occurring of existing at same time as something else

Question 12

what are the causes of type A?

Answer 12

pharmaceutical variation, pharmacokinetic variation, pharmacodynamic variation

Question 13

what is pharmaceutical variation?

Answer 13

changes in bioavailability, out of date formulations, contamination

Question 14

what is an example of outdated drug use?

Answer 14

outdated tetracycline breaks down to produce anhydrotetracycline which is toxic and leads to Fanconi’s syndrome

Question 15

what is fanconi’s syndrome?

Answer 15

impairment of the proximal tube function, substances normally reabsorbed into the blood are lost in urine

Question 16

what is pharmacokinetic variation caused by in type A?

Answer 16

liver disease, renal disease, cardiac disease and drug interactions

Question 17

how does liver failure effect pharmacokinetic variation?

Answer 17

severe hepatitis or advanced cirrhosis can reduce the clearance of drugs

Question 18

what drugs have a low therapeutic ratio?

Answer 18

phenytoin, theophylline and warfarin

Question 19

what does pharmacodynamic variation effect for type A?

Answer 19

changes in fluid/electrolyte balance and drug interactions

Question 20

what is an example of a negative drug interaction that causes pharmacodynamic variation?

Answer 20

digoxin which is used to treat heart failure blocks the pump and competes with K, yet when K levels are low, the digoxin can bind more easily and have a dangerous level of effect

Question 21

what are the features of type B?

Answer 21

uncommon, not related to the pharmacological action of the drug, unpredictable and high mortality

Question 22

how is type B reaction managed?

Answer 22

withhold and avoid in future

Question 23

what are the two negative effect that come with type B reactions?

Answer 23

immunological and pseudo allergic reactions

Question 24

what is an example of an immunological reactions?

Answer 24

allergy to penicillin which happens as a result of degradation products combining with body proteins and become antigenic

Question 25

what is a pseudoallergic reaction?

Answer 25

reactions that resemble allergic reactions but for which no immunological basis has been found

Question 26

what is an example of pseudo allergic action?

Answer 26

aspirin-sensitive asthmatics where aspirin triggers attacks or ampicillin rash

Question 27

what are the adaptive effects of type C?

Answer 27

tolerance, adrenal suppression and tar dive dyskinesia

Question 28

what drugs cause tolerance?

Answer 28

narcotic analgesics

Question 29

what drugs cause adrenal suppression?

Answer 29

corticosteroids such as hydrocortisone

Question 30

what is tardive dyskinesia?

Answer 30

repetitive facial movements as a result of long term antipsychotic drug use

Question 31

how are glucocorticoid hormones controlled?

Answer 31

negative feedback

Question 32

what are glucocorticoids used to treat?

Answer 32

chronic inflammatory conditions such as rheumatoid arthritis

Question 33

what does prolonged treatment using glucocorticoids cause?

Answer 33

suppression of glucocorticoid synthesis by the adrenal cortex

Question 34

how can the adrenal cortex be allowed to recover?

Answer 34

gradual withdrawal of exogenous corticoids

Question 35

what are the features of type D?

Answer 35

uncommon, usually dose related, occurs of becomes apparent sometime after use of the drug

Question 36

how is type D managed?

Answer 36

often untreatable

Question 37

how is type D related to carcinogenesis?

Answer 37

increased risk with oestrogen such as in contraceptives and HRT

Question 38

what are the effects on reproduction for type D?

Answer 38

impaired fertility and teratogenesis

Question 39

how is fertility effected by drugs that show type D reactions?

Answer 39

cytotoxic drugs such as cyclophosphamide that are used in chemotherapy effect fertility

Question 40

what is teratogenesis and how is it effected by type D drugs?

Answer 40

thalidomide effecting the development of limbs

Question 41

what is type E drug reactions?

Answer 41

end of treatment

Question 42

what are the features of type E drug reaction?

Answer 42

uncommon and occurs soon after withdrawal of the drug

Question 43

what are examples of reactions associated with type E?

Answer 43

opiate withdrawal syndrome, mycardial ischaemia which is beta blocker withdrawal

Question 44

how are type E reactions managed?

Answer 44

reintroduce and withdraw slowly

Question 45

what disease can be caused by type E?

Answer 45

rebound phenomena

Question 46

what is rebound phenomena?

Answer 46

withdrawal of beta blockers that causes rebound tachycardia which then can cause a myocardial infarction

Question 47

what are the features of type F, failure of therapy?

Answer 47

common, dose-related and often caused by drug interactions

Question 48

what is an example of a type F reaction?

Answer 48

inadequate dosage of oral contraceptive, particularly when used with specific metabolism enzyme inducers e.g. rifampicin

Question 49

how is type F managed?

Answer 49

increase the dosage and consider effects of concomitant therapy

Question 50

how is pharmacogenetic variation caused in type F?

Answer 50

variation in receptor structure and pseudocholinesterase deficiency

Question 51

what is an example of phamacogenetic variation in type F?

Answer 51

pseudocholinesterase deficiency

Question 52

what is pseudocholinesterase deficiency?

Answer 52

succinylcholine which is used as a muscle relaxant can cause prolonged apnoea in patients who lack the enzyme to break it down

Question 53

what is an example of receptor variation in type F?

Answer 53

different variants of the beta-2 receptor in the lungs show a reduction in the response to agonists so less bronchodilation

Question 54

how can pharmacokinetic interactions interfere with absorption?

Answer 54

tetracycline binds to calcium and iron and so leads to reduced absorption

Question 55

what interactions cause an effect on pharmacokinetic action?

Answer 55

interference of absorption, competition for plasma protein, inhibition of metabolic enzymes and competition for elimination pathways

Question 56

how does competition for plasma protein binding occur?

Answer 56

warfarin vs aspirin

Question 57

how does inhibition of metabolic enzymes occur?

Answer 57

probenecid slows excretion of penicillin, NSAIDS inhibit excretion of lithium

Question 58

what is an example of pharmacodynamic interaction?

Answer 58

proponalol which is used to treat angina, can reduce the effect of salbutamol which is used to treat asthma

Question 59

how do levodopa and antipsychotics interact?

Answer 59

levodopa works by increasing synaptic dopamine levels in Parkinson's disease yet antipsychotics block dopamine receptors to reduced the effect of levodopa