Can Dayquil (Dextromethorphan) and Nyquil (Dextromethorphan and Acetaminophen) cause liver damage?

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Last updated: April 25, 2025View editorial policy

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From the Guidelines

DayQuil and NyQuil can potentially harm your liver if taken incorrectly or in excessive amounts, but the risk is low if the daily dose of acetaminophen is limited to ≤4 g per day. According to the 2022 klca-ncc korea practice guidelines for the management of hepatocellular carcinoma 1, amounts of less than 4 g per day of acetaminophen are very unlikely to cause clinically significant hepatotoxicity. However, when other analgesics are added as a fixed dose combination, the dose of acetaminophen should be limited to ≤325 mg per dosage unit to reduce liver damage induced by acetaminophen.

Some key points to consider when taking DayQuil and NyQuil:

  • The recommended maximum daily dose of acetaminophen is 4 g for adults, and both DayQuil and NyQuil typically contain 325-650 mg per dose 1.
  • To protect your liver, never exceed the recommended dosage on the packaging, don't take multiple acetaminophen-containing products simultaneously, avoid alcohol while using these medications, and don't use them for more than 10 days without consulting a healthcare provider.
  • People with existing liver conditions, heavy alcohol users, and those taking other medications that affect the liver should be especially cautious and consult their doctor before using these products 1.
  • NSAIDs, which are sometimes combined with acetaminophen in cold and flu medications, can cause side effects such as nephrotoxicity, gastric ulcers or bleeding, and decompensation in patients with liver cirrhosis, and their use must be avoided as much as possible 1.

It's essential to follow the recommended dosage and guidelines to minimize the risk of liver damage when taking DayQuil and NyQuil. If you have concerns or questions, consult your healthcare provider for personalized advice.

From the FDA Drug Label

WARNINGS Liver warning: This product contains acetaminophen. Severe Liver damage may occur if you take • more than 6 caplets in 24 hours, which is the maximum daily amount • with other drugs containing acetaminophen • 3 or more alcoholic drinks everyday while using this product

Dayquil and Nyquil can hurt the liver if they contain acetaminophen and are taken in excess, with other acetaminophen-containing drugs, or with excessive alcohol consumption.

  • Severe liver damage may occur under these conditions. 2

From the Research

Dayquil and Nyquil Liver Damage

  • Dayquil and Nyquil are over-the-counter medications that contain acetaminophen, which can cause liver damage in certain individuals 3, 4.
  • Chronic abusers of alcohol may be particularly susceptible to hepatotoxicity from acetaminophen, as seen in a case report of two patients who experienced liver injury after ingesting Nyquil 3.
  • Patients with underlying liver disease are at higher risk of poor outcomes from acetaminophen overdose, and limited knowledge of acetaminophen may contribute to elevated rates of overdose and acute liver failure 5.

Acetaminophen and Liver Function

  • A randomized study found that acetaminophen in doses of 4 g/d did not affect liver function in alcoholic patients, but this does not rule out the possibility of acetaminophen-induced liver failure in patients with pre-existing liver disease or those who continue to drink 6.
  • The underlying mechanisms of acetaminophen-induced liver injury are still not fully understood, and the incidence of acetaminophen-associated hepatotoxicity has increased over the past few decades 4.

Safe Use of Acetaminophen in Liver Disease

  • A systematic review found that high-quality trials are not available to support the use of decreased acetaminophen doses in compensated cirrhosis patients, and acetaminophen can be a safe analgesic in patients with compensated hepatic dysfunction after careful analysis of patient-specific factors 7.
  • Patients with liver disease have critically low levels of knowledge of acetaminophen, putting them at risk of acetaminophen overdose and undermedication, and increasing education efforts regarding acetaminophen dosage and safety is essential to minimizing acetaminophen overdose rates and optimizing pain management 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Nyquil-associated liver injury.

The American journal of gastroenterology, 1989

Research

Limited Knowledge of Acetaminophen in Patients with Liver Disease.

Journal of clinical and translational hepatology, 2016

Research

Does acetaminophen affect liver function in alcoholic patients?

The Journal of family practice, 2003

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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