Does Marijuana Interact with NyQuil?

cold medicine NyQuil with marijuana

Table of contents

  1. What Is NyQuil?
  2. Uses and How It Works
  3. Potential Benefits and Risks of Mixing Cannabis and NyQuil
  4. What to Do If You Need to Use Both NyQuil and Marijuana
  5. The Bottom Line

Combining the cold medicine NyQuil with marijuana is not known to be dangerous, but the sedative effects of NyQuil may be enhanced if the two are combined. NyQuil contains two active ingredients, doxylamine, and dextromethorphan, shown to have a moderate drug-drug interaction with cannabis. Acetaminophen (Tylenol, paracetamol), also in NyQuil, is not known to have any adverse reaction when combined with cannabis.

What Is NyQuil?

NyQuil is a trademarked medication used for pain relief and treating cold symptoms like sore throat and is available as a liquid or liquicap. It is sometimes sold with DayQuil, so NyQuil is considered the nighttime medication.

Such cold medications (anti-tussives) usually contain one or a combination of analgesics, antihistamines, and decongestants.

Uses and How It Works

NyQuil is a cold medicine usually taken to relieve some of the symptoms of the common cold, influenza, or other similar upper respiratory tract conditions. It contains three active ingredients:

  1. Acetaminophen (Tylenol, paracetamol): An analgesic relieves pain and reduces fever. Acetaminophen relieves inflammatory pain via the CB1 receptor, inhibiting the uptake and degradation of anandamide. The liver metabolizes acetaminophen into the cannabinoid, N-arachidonoylphenolamine.
  2. Dextromethorphan(Robitussin, Delsym): A cough suppressant with stimulant properties in lower doses and sedative properties in moderate to high doses. Dextromethorphan is in the morphinan and anti-tussive class of medications and has multiple mechanisms of action. Dextromethorphan acts as a nonselective serotonin reuptake inhibitor and a sigma-1 receptor agonist. Dextromethorphan is not only used for cough suppression but also for withdrawal associated with opioid use disorder and some instances of treatment-resistant major depressive disorder when combined with bupropion.
  3. Doxylamine (Unisom, Vicks Formula 44 in combination with Dextromethorphan) – an antihistamine used to treat sneezing, runny nose, itching, and inability to get to sleep. Doxylamine is an anti-cholinergic, meaning it blocks the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system (CNS and PNS). Anticholinergic drugs are often used to treat dizziness, GI disorders, insomnia, and various respiratory disorders (e.g., asthma, chronic obstructive pulmonary disorder or COPD, chronic bronchitis).

Potential Benefits and Risks of Mixing Cannabis and NyQuil

Although there seems to be no dangerous interaction between cannabis and NyQuil, both medications have sedative effects that can interact with each other.

Potential Benefits

Potential Risks

  • Cannabinoids in cannabis, like cannabidiol (CBD) and tetrahydrocannabinol (THC), can desensitize liver enzymes metabolized through the cytochrome P450 pathway. This could potentially increase levels of doxylamine and dextromethorphan and increase the chances of adverse side effects such as dizziness, extreme drowsiness and sedation, nausea and vomiting, hypotension, hypertension (decrease or increase in blood pressure), sweating, fever, and many more.
  • Smoking weed may cancel out NyQuil’s cough suppressant properties.
  • Cannabinoids are immunomodulators that can dampen inflammation, and this can be useful in chronic conditions where inflammation is out of control (dysinflammation). Still, when battling infections in the short term, this may inhibit the immune system from doing its job.
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What to Do If You Need to Use Both NyQuil and Marijuana

Suppose you are suffering from a cold or flu and are using NyQuil. In that case, it is wise to reduce or even stop your cannabis use unless instructed otherwise (e.g., you are utilizing medical cannabis and CBD to reduce seizures or other health problems).

The Bottom Line

Although there are no known significant dangers when combining cannabis and NyQuil, it’s not a good idea for most people unless recommended by a doctor.

Two of the three active ingredients in NyQuil — doxylamine, and dextromethorphan — are listed as having a moderate drug-drug interaction with cannabis. This is because both have sedative effects that may increase when used together to treat temporary medical conditions in the body. Cannabis may also interfere with how the active ingredients in NyQuil are metabolized, increasing the chances of an adverse effect. Going beyond the recommended dose of NyQuil also causes several adverse effects, so it is best not to mix cannabis and NyQuil.

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