50 mg PO TID OR 100 mg PO BID x4 weeks, THEN
50 mg PO BID
50 mg extract generally standardized to contain 7.5 mg petasins PO BID
Leaf extract: 8 mg of petasin, 1 tablet PO TID-QID
Seasonal Allergic Rhinitis (Hay Fever)
Contains pyrrolizidine alkaloids (especially in roots), which may be carcinogenic & hepatotoxic (commercial preparations are generally pyrrolizidine-free)
Pregnancy & Lactation
Pregnancy Category: N/A
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Mechanism of Action
Contains Petasin, a sesquiterpene ester, that has leukotriene inhibitory function
Efficacy: clinical studies show efficacy similar to fexofenadine in relieving hay fever symptoms & greater effctivity over placebo in migraine prophylaxis