Herbal remedies may be associated with adverse reactions. The toxicity of any therapeutic agent can be classified into groups based on a number of features.
Parameters using in classification:
(1) acute or delayed effect
(2) predictability
(3) associated dose
Timing |
Predictability |
Dose |
Other |
Type |
acute |
predictable |
high dose (dose dependent) |
avoid with lower dose |
A |
acute or delayed |
idiosyncratic (unpredictable) |
any |
can be life threatening |
B |
delayed (weeks or months) |
predictable or expected |
chronic use |
may be cumulative |
C |
delayed (months or years) |
variable |
any |
carcinogenic, teratogenic |
D |
where:
• Pharmacogenetics can have an effect, primarily on Type A.
• An allergic or other immune reaction may be involved in a Type B reaction.
• A drug with predictable toxicity at low dose would probably not be approved.
• Carcinogenicity may be affected by the presence of other risk factors such as smoking.
• An herbal remedy may be associated with more than 1 type of adverse reaction.
Specialty: Pharmacology, clinical