Dwight asked
How fast does NyQuil work? How long should it take to feel drowsy?
Answer
NyQuil is a combination ingredient product that is used for cold/flu symptom relief as well as for it's sedative effects. It contains the following active ingredients:
- Acetaminophen (analgesic/fever reducer)
- Dextromethorphan (cough suppressant)
- Doxylamine succinate (sedating antihistamine)
How Fast Does NyQuil Work?
NyQuil has a fast onset of action and individuals will generally notice effects about 20 to 30 minutes after taking a dose by mouth. There are multiple active ingredients in NyQuil, all with slightly different characteristics. Below, we discuss each in detail.
Acetaminophen
Acetaminophen is an analgesic and fever reducer. In addition to NyQuil, it is the active ingredient in Tylenol. After taking by mouth, acetaminophen begins to work in about 30 minutes and reaches peak concentrations in the blood in 30 to 60 minutes, depending on the individual. As NyQuil is a liquid, you can expect acetaminophen to being working faster than the solid dosage forms.
It is important to note that acetaminophen absorption is slightly delayed if taken with food. Therefore, if you want the fastest effects, take it on an empty stomach.
Dextromethorphan
Dextromethorphan is a cough suppressant and is quickly absorbed after taking by mouth. Most studies indicate that the cough suppressant effects of dextromethorphan will occur within 15 to 30 minutes after dosing.
Doxylamine
Doxylamine is a sedating antihistamine and is responsible for the sedative effects of NyQuil (in addition to the alcohol content). The onset of action is about 30 minutes but peak concentrations in the blood occur nearly 2 to 3 hours after taking by mouth. This means that while you will feel the effects of doxylamine relatively quickly, it can take a few hours for the drug to reach max effect.
Summary
NyQuil is a combination ingredient medication and contains 3 active ingredients. The onset of action of each ingredient in NyQuil is about 15 to 30 minutes and you will be begin to feel drowsy in that time frame. The maximum sedative effects however (from the doxylamine), won't occur until 2 to 3 hours after dosing.
