Rawlins and Thompson, 1977
|
Type A(Augmented) |
Type B(Bizzare) |
| Pharmacologically predictable |
Yes |
No |
| Dose dependent |
Yes |
No |
| Frequency |
Common |
Rarer |
| Incidence |
High |
Low |
| Mortality |
Low |
High |
| Treatment |
Adjust Dose |
Stop the Drug |
Rawlins MD, Thompson JW. Pathogenesis of adverse drug reactions. In: Davies DM, ed. Textbook of adverse drug reactions . Oxford : Oxford University Press, 1977: 10.
Type of reaction |
Mnemonics |
Features |
A: dose related |
Augmented |
Related to pharmacology (toxic effect or side effect--for example, digoxin toxicity) |
B: non-dose related |
Bizarre |
Unrelated to pharmacology (idiosyncratic for example, malignant hyperthermia, or immunological--for example, penicillin rash) |
C: dose and time related |
Continuous or chronic |
Related to cumulative drug use--for or chronic example, NSAID induced renal failure |
D: delayed effect |
Delayed |
Apparent only some time after use of drug--for example, thalidomide in first trimester and phocomelia limb defects |
E: Withdrawal |
Delayed |
Apparent only some time after use of drug--for example, thalidomide in first trimester and phocomelia limb defects |
F: Failure of therapy |
Failure |
Results from the ineffective
treatment
(previously excluded from analysis according
to WHO definition)
e.g: accelerated hypertension because
of inefficient control |
Edwards IR, Aronson JK. Adverse drug reactions: definitions, diagnosis and management. Lancet 2000; 356:1255-9.
Aronson JK. Drug therapy. In: Haslett C, Chilvers ER, Boon NA, Colledge NR, Hunter JAA, eds. Davidson's principles and practice of medicine 19th ed. Edinburgh: Elsevier Science, 2002:147-63.
Time related classification of adverse drug reactions
1. Time Independent
| Type of reaction |
Examples |
Implications |
Due to change in dose or concentration
(pharmaceutical effect) |
Toxicity due to increased systemic availability |
Beware of changing formulations of some drugs (e.g. modified-release formulations of lithium) |
Due to change in dose or concentration (pharmacokinetic effects) |
Digitalis toxicity due to renal insufficiency |
Forewarn the patient.
Monitor carefully throughout treatment.
Alter dosage when pharmacokinetics change (e.g. renal insufficiency).
Avoid interacting drugs. |
Occurs without change in dose (pharmacodynamic effects) |
Digitalis toxicity due to hypokalaemia |
Forewarn patient.
Monitor carefully throughout treatment. Avoid precipitating (pharmacodynamic) factors.
Avoid interacting drugs |
2. Time dependant
| Type of reaction |
Examples |
Implications |
Rapid (due to rapid administration) |
Red man syndrome (vancomycin) |
Administer slowly |
First dose reactions |
Hypotension (a 1 adrenoceptor antagonists and angiotensin converting enzyme inhibitors) |
Take special precautions for the first dose |
Early (abates with repeated exposure) |
Adverse reactions that involve tolerance (e.g. nitrate induced headache) |
Monitor during early stages.
Give appropriate reassurance.
Expect adverse effects if strategies to avoid tolerance are adopted. |
Intermediate (risk increases at first, then diminishes) |
Venous thromboembolism (antipsychotic drugs) |
Monitoring not needed after the high risk period unless susceptibility changes.
Withdraw drug if a reaction develops. |
Late (risk increases with time) |
Osteoporosis (corticosteroids) |
Assess baseline function.
Forewarn the patient.
Monitor periodically during prolonged treatment. |
Delayed |
Carcinogenesis (cyclosporine, diethylstilbestrol) |
Avoid or screen.
Counsel or forewarn the patient. |
Joining the DoTS: new approach to classifying adverse drug reactions.
Aronson JK , Ferner RE . BMJ. 2003 Nov 22;327(7425):1222-5
Classification based on frequency
| |
> 1/10 |
|
| |
|
|
| |
|
|
| |
> 1/10,000 and < 1,000 |
|
| |
< 1/10,000 |
|
Based on avoidability of the ADR s
| Definitely avoidable |
The ADR was due to a drug treatment procedure inconsistent with present day knowledge of good medical practice |
Possibly avoidable |
The ADR could have been avoided by an effort exceeding the obligatory demands of present day knowledge of good medical practice |
Unavoidable |
The ADR could not have been avoided by any reasonable means |
Hallas J, Harvald B, Gram LF, Grodum E, Prosen K, Haghfelt T, et al. Drug related hospital admissions: the role of definitions and intensity of data collection, and the possibility of prevention. J Intern Med 1990;228: 83-90
Based on severity
Severity |
Description |
Mild |
No antidote or treatment is required; hospitalization is not prolonged |
Moderate |
A change in treatment (e.g., modified dosage, addition of a drug), but not necessarily discontinuation of the drug, is required; hospitalization may be prolonged, or specific treatment may be required |
Severe |
An ADR is potentially life threatening and requires discontinuation of the drug and specific treatment of the ADR |
Lethal |
An ADR directly or indirectly contributes to a patient's death |
Common Terminology for Adverse Events (CTCAE)
National Cancer Institute
Grading adverse events
By this grading scale, all adverse events are classified as follows:
0=No adverse event or within normal limits
1=Mild adverse event
2=Moderate adverse event
3=Severe and undesirable adverse event
4=Life-threatening or disabling adverse event
5=Death related to adverse event
Common Terminology for Adverse Events (CTCAE)
|
