Acetaminophen / Dichloralphenazone / Isometheptene Mucate Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 14, 2023.

Applies to acetaminophen / dichloralphenazone / isometheptene mucate: oral capsule.

Precautions

Check with your doctor:

• If the medicine stops working as well as it did when you first started using it. This may mean that you are in danger of becoming dependent on the medicine. Do not try to get better relief by increasing the dose.
• If you are having headaches more often than you did before you started using this medicine. This is especially important if a new headache occurs within 1 day after you took your last dose of headache medicine, headaches begin to occur every day, or a headache continues for several days in a row. This may mean that you are dependent on the medicine. Continuing to take this medicine will cause even more headaches later on. Your doctor can give you advice on how to relieve the headaches.

Check the labels of all nonprescription (over-the-counter [OTC]) and prescription medicines you now take. Taking other medicines that contain acetaminophen together with this medicine may lead to an overdose. If you have any questions about this, check with your health care professional.

This medicine may cause some people to become drowsy, dizzy, or less alert than they are normally. These effects may be especially severe if you also take CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness) together with this medicine. Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; antiemetics (medicines that prevent or relieve nausea or vomiting), and anesthetics. If you are not able to lie down for a while, make sure you know how you react to this medicine or combination of medicines before you drive, use machines, or do anything else that could be dangerous if you are drowsy or dizzy or are not alert.

Do not drink alcoholic beverages while taking this medicine. To do so may increase the chance of liver damage caused by acetaminophen, especially if you drink large amounts of alcoholic beverages regularly. Also, because drinking alcoholic beverages may make your headaches worse or cause new headaches to occur, people who often get headaches should probably avoid alcohol.

Other side effects

Some side effects of acetaminophen / dichloralphenazone / isometheptene mucate may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Serious side effects

Along with its needed effects, acetaminophen / dichloralphenazone / isometheptene mucate may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur while taking acetaminophen / dichloralphenazone / isometheptene mucate:

Symptoms of dependence on this medicine

• headaches, more severe and/or more frequent than before

Symptoms of acetaminophen overdose

• diarrhea
• increased sweating
• loss of appetite
• nausea or vomiting
• pain, tenderness, and/or swelling in the upper abdominal (stomach) area
• stomach cramps or pain

For healthcare professionals

Applies to acetaminophen / dichloralphenazone / isometheptene mucate: oral capsule.

Hypersensitivity adverse events

Hypersensitivity side effects including transient dizziness and skin rash have been reported with the use of acetaminophen/dichloralphenazone/isometheptene. Hypersensitivity reactions, including anaphylaxis and fixed drug eruptions have been reported rarely in association with acetaminophen use.^[Ref]

Transient dizziness and skin rash can usually be eliminated by reducing the dose of acetaminophen/dichloralphenazone/isometheptene.^[Ref]

Hepatic

Hepatic side effects including severe and sometimes fatal dose dependent hepatitis have been reported with the use of acetaminophen in alcoholic patients. Hepatotoxicity has been increased during fasting.^[Ref]

Alcoholic patients may develop hepatotoxicity after even modest doses of acetaminophen. In healthy patients, approximately 15 grams of acetaminophen is necessary to deplete liver glutathione stores by 70% in a 70 kg person. However, hepatotoxicity has been reported following smaller doses. Glutathione concentrations may be repleted by the antidote N-acetylcysteine. One case report has suggested that hypothermia may also be beneficial in decreasing liver damage during overdose.

In a recent retrospective study of 306 patients admitted for acetaminophen overdose, 6.9% had severe liver injury but all recovered. None of the 306 patients died.

One study has suggested that acetaminophen may precipitate acute biliary pain and cholestasis. The mechanism of this effect may be related to inhibition of prostaglandin and alterations in the regulation of the sphincter of Oddi.

Cases of acute pancreatitis have been reported rarely with the use of acetaminophen.^[Ref]

Gastrointestinal

Gastrointestinal side effects have been rare with the use of acetaminophen except in alcoholics and after overdose.^[Ref]

Renal

Renal side effects including acute tubular necrosis and interstitial nephritis have been rare with the use of acetaminophen. Adverse renal effects have been most often observed after overdose, after chronic abuse (often with multiple analgesics), or in association with acetaminophen-related hepatotoxicity.^[Ref]

Acute tubular necrosis with acetaminophen use usually occurs in conjunction with liver failure, but has been observed as an isolated finding in rare cases. A possible increase in the risk of renal cell carcinoma has been associated with chronic acetaminophen use as well.

A recent case-control study of patients with end-stage renal disease suggested that long term consumption of acetaminophen may significantly increase the risk of end-stage renal disease particularly in patients taking more than two pills per day.^[Ref]

Hematologic

Hematologic side effects including rare cases of thrombocytopenia associated with acetaminophen have been reported. Methemoglobinemia with resulting cyanosis has also been observed in the setting of acute overdose.^[Ref]

Dermatologic

Dermatologic side effects including erythematous skin rashes associated with acetaminophen have been reported rarely. Acetaminophen associated bullous erythema and purpura fulminans have also been reported.^[Ref]

Respiratory

Respiratory side effects including a case of acetaminophen-induced eosinophilic pneumonia have been reported.^[Ref]

Cardiovascular

Cardiovascular side effects including at least two cases of hypotension have been reported following the administration of acetaminophen.^[Ref]

Two cases hypotension have been reported following the administration of acetaminophen. Both patients experienced significant decreases in blood pressure. One of the two patients required pressor agents to maintain adequate mean arterial pressures. Neither episode was associated with symptoms of anaphylaxis. Neither patient was rechallenged after resolution of the initial episode.^[Ref]

See also:

Further information

Acetaminophen/dichloralphenazone/isometheptene mucate side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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