Acetaminophen Side Effects

As of June 30, 2024, the most commonly reported side effects of acetaminophen include toxicity, overdose, vomiting, suicide and nausea. This represents side effects information reported to the FDA from 1969 to 2024.

According to the FDA Adverse Events Reporting System (FAERS) Public Dashboard, the FDA received over 14,400 reports of side effects in 2023 alone from individuals taking acetaminophen. Of these side effects, toxicity was the most frequently reported reaction. Vomiting, pain and nausea were other frequently reported side effects. Suicide (attempted or completed) and overdose (accidental or intentional) also make up a significant percentage of reported side effects.

Disclaimer: Reports sent to the FDA don’t necessarily mean the drug caused an adverse event. Consult a health care professional before stopping or changing medication.

More than 75% of all reported cases included severe side effects, and over 20% of the reported cases resulted in death after taking acetaminophen. While these stats may seem alarming, these numbers represent only those cases reported to the FDA — a very small percentage of people taking acetaminophen.

“I would strongly recommend consulting with a provider before using these medications if you need to take them for a prolonged duration,” Dr. Su Hlaing Hnin, a board-certified internal medicine physician with Medical Offices of Manhattan, told Drugwatch. “I would also recommend seeing a provider to find out the cause of the pain and get an appropriate evaluation and management.”

Acetaminophen Boxed Warnings

Prescribed acetaminophen carries an FDA boxed warning for potential liver injury if patients take more than the recommended dose. There are no warnings on over the counter (OTC) versions of the drug. On June 14, 2024, the FDA issued a proposed administrative order to require a warning on OTC acetaminophen products about potentially serious skin reactions.

Adults report nausea, vomiting, headaches and insomnia as the most common side effects of acetaminophen. The most common side effects for pediatric patients include nausea, vomiting, constipation, itching and agitation.

Many people can safely take acetaminophen with no side effects. When common reactions do occur, they typically last for one or two days. Intravenous and rectal administration of acetaminophen may increase the likelihood of adverse reactions.

Serious side effects of acetaminophen include overdose or hepatotoxicity, also known as liver damage.

“It can damage the liver at high doses or with long-term use,” Dr. Taher Saifullah, founder of the Spine and Pain Institute in Los Angeles, told Drugwatch. He warned that overdosing on acetaminophen is highly toxic to the liver.

While acetaminophen is widely available and largely considered safe, these serious side effects can be life-threatening.

There are also potential risks associated with taking acetaminophen during pregnancy, including a possible increased risk of children developing neurological conditions such as ADHD and autism. As of June 2024, there are several hundred related legal cases against drug manufacturers pending in federal court. If you are pregnant or planning to become pregnant, discuss those risks with your health care provider before taking products containing acetaminophen.

Acetaminophen and Liver Damage

In 2018, the FDA lowered the recommended dosage instructions on acetaminophen to reduce the chance of overdose and liver damage. The maximum daily dose of acetaminophen is 4,000 mg. It’s important to note that taking multiple medications containing acetaminophen makes tracking totals difficult, which can lead to you taking more than the recommended limit.

Certain conditions can also increase the chance of developing liver damage from acetaminophen. If you have a history of liver disease or consume three or more alcoholic drinks per day, discuss the risks of taking acetaminophen with your health care provider.

Some cases of liver damage may resolve on their own, but in other cases, the condition can result in multiple organ failure or death. If you suspect liver damage while taking acetaminophen, seek medical attention as soon as possible, as a health care provider can treat liver damage if caught early.

Treatment options for liver damage include activated charcoal, intravenous fluids or oral n-acetylcysteine. Do not try to treat an acetaminophen overdose or liver damage at home; a doctor or other medical professional must administer these medications. Treatment is most effective when it starts within eight hours of the initial overdose.

Acetaminophen Overdose

An acetaminophen overdose occurs in four stages that can last for several weeks in total. The first stage occurs in the first 24 hours after the overdose. You may feel clammy or sweaty and have little appetite. Nausea, vomiting and cramping are common symptoms.

The second phase of acetaminophen overdose occurs between 18 and 72 hours after ingestion. Initial symptoms continue and may be accompanied by a rapid heart rate and low blood pressure.

The third phase is the most serious. Occurring between 72 and 96 hours after the initial overdose, this is when signs of liver failure may develop. Symptoms of liver failure include bleeding, jaundice, low blood pressure and diminished brain function. Liver and other organ failure during this phase can result in death.
After medical treatment, the final stage of acetaminophen overdose is recovery, which can last from four days to three weeks. Your symptoms gradually resolve during this time.

Acetaminophen and Skin Reactions

Severe skin reactions are possible, although rare, for people taking acetaminophen. Serious reactions include Stevens-Johnson syndrome, toxic epidermal necrolysis and acute generalized exanthematous pustulosis, a condition that causes sudden pustules on the skin.

Unlike a mild rash or itching, these skin reactions are serious and can be fatal. They may start with flu-like symptoms and progress to skin necrosis. Seek medical attention immediately if you suspect you are having a serious skin reaction to acetaminophen.

If you are concerned with possible acetaminophen side effects, nonsteroidal anti-inflammatory medications (NSAIDs) are a popular alternative to acetaminophen for pain relief. They are widely available without a prescription and safe for many people.

But NSAIDs also have side effects, and some people cannot take them safely.

“If you’re experiencing chronic pain, consult a doctor to develop a personalized treatment plan,” Dr. Saifullah said. “[Over-the-counter] meds might play a role, but they shouldn’t be the only solution.”