Echinacea - DayQuil Severe (acetaminophen, dextromethorphan, phenylephrine, guaifenesin) Interaction

Interaction Details

acetaminophen, dextromethorphan, phenylephrine, guaifenesin is classified as belonging to the following category: Dayquil Severe

Echinacea is reported to have varying effects on a number of Cytochrome P450 metabolizing enzymes in the liver, including CYP1A2 and CYP3A4, which play a role in acetaminophen and dextromethorphan metabolism (both contained in DayQuil Severe), respectively. Studies have reported both enzyme inhibition and induction, making it difficult to predict clinically significant drug interactions with reliability. Specific drug interaction studies reporting definitive results are rare, and potential drug interactions involving echinacea should likely be taken on a case-by-case basis. Based on what we know about how acetaminophen and dextromethorphan are metabolized, the risk of a clinically significant interaction between echinacea and DayQuil Severe is low.

Interaction Rating

Likelihood of Occurrence

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Pharmacist Analysis

The 'original' DayQuil Cold & Flu contains:

• Acetaminophen (pain reliever)
• Dextromethorphan (cough suppressant)
• Guaifenesin (expectorant)

The 'Severe' version adds on phenylephrine, a nasal decongestant.

In regard to interactions, echinacea has been reported to affect a number of different CYP metabolizing enzymes in the liver, including CYP1A2 and CYP3A4.

This is of interest as Tylenol (acetaminophen) is partially metabolized by CYP1A2 while dextromethorphan is partially metabolized by CYP3A4. Theoretically, echinacea, via inhibition of these liver metabolizing enzymes, could increase the concentrations of each of these drugs, increasing the risk of side effects.

Regardless, the risk of a clinically significant drug interaction here is low.

For starters, while echinacea may inhibit CYP1A2 to some degree, it has not been reported as being responsible for causing adverse effects when combined with acetaminophen when used at recommended dosages, likely due to the fact that acetaminophen has multiple metabolic pathways (e.g., glucuronidation and sulfate conjugation in addition to CYP1A2).

Additionally, dextromethorphan is primarily metabolized via CYP2D6, which echinacea isn't known to affect to any significant degree.

While you should be aware of the potential interaction here between echinacea and DayQuil, it is unlikely the combination will cause any serious adverse effects.

Echinacea - More Interactions

Echinacea interacts with 787 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.