Acetaminophen and phenyltoloxamine

Name: Acetaminophen and phenyltoloxamine

What happens if I miss a dose?

Since this medicine is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What should I avoid while taking acetaminophen and phenyltoloxamine?

Avoid drinking alcohol. It may increase your risk of liver damage while taking acetaminophen, and can increase certain side effects of phenyltoloxamine.

Ask a doctor or pharmacist before using any other cold, allergy, pain, or sleep medication. Acetaminophen (sometimes abbreviated as APAP) is contained in many combination medicines. Taking certain products together can cause you to get too much acetaminophen which can lead to a fatal overdose. Check the label to see if a medicine contains acetaminophen or APAP.

This medicine may cause blurred vision or impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

For the Consumer

Applies to acetaminophen / phenyltoloxamine: oral liquid, oral tablet, oral tablet extended release

For Healthcare Professionals

Applies to acetaminophen / phenyltoloxamine: oral liquid, oral tablet, oral tablet extended release

Hepatic

Hepatic side effects including severe and sometimes fatal dose dependent hepatitis has been reported with the use of acetaminophen in alcoholic patients. Hepatotoxicity has been increased during fasting. Several cases of hepatotoxicity from chronic acetaminophen therapy at therapeutic doses have also been reported despite a lack of risk factors for toxicity.[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.

A 19-year-old female developed hepatotoxicity, reactive plasmacytosis and agranulocytosis followed by a leukemoid reaction after acute acetaminophen toxicity.[Ref]

Gastrointestinal

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.[Ref]

Gastrointestinal side effects including nausea, vomiting, and abdominal pain have been reported frequently with the use of butalbital. Gastrointestinal side effects are rare with acetaminophen use, except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with the use of acetaminophen.[Ref]

Renal

Acute tubular necrosis 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]

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

Hypersensitivity

Hypersensitivity side effects, including anaphylaxis and fixed drug eruptions, have been reported rarely in association with acetaminophen use.[Ref]

Hematologic

Hematologic side effects including rare cases of thrombocytopenia associated with acetaminophen have been reported. Acute thrombocytopenia has also been reported as having been caused by sensitivity to acetaminophen glucuronide, the major metabolite of acetaminophen. Methemoglobinemia with resulting cyanosis has also been observed in the setting of acute overdose.

Hematologic side effects such as hemolytic anemia, thrombocytopenia, and agranulocytosis have been rarely caused by antihistamines.[Ref]

Dermatologic

Dermatologic side effects including erythematous skin rashes associated with acetaminophen have been reported, but are rare. 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 two cases of hypotension have been reported following the administration of acetaminophen.

Cardiovascular side effects from the use of antihistamines have included hypotension, tachycardia, and palpitations.[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]

Metabolic

Metabolic side effects including metabolic acidosis have been reported following a massive overdose of acetaminophen.[Ref]

In the case of metabolic acidosis, causality is uncertain as more than one drug was ingested. The case of metabolic acidosis followed the ingestion of 75 grams of acetaminophen, 1.95 grams of aspirin, and a small amount of a liquid household cleaner. The patient also had a history of seizures which the authors reported may have contributed to an increased lactate level indicative of metabolic acidosis.[Ref]

Some side effects of acetaminophen / phenyltoloxamine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Usual Adult Dose for Cold Symptoms

Acetaminophen-phenyltoloxamine 325 mg-30 mg oral tablet:
1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-50 mg oral tablet:
1/2 to 1 tablet orally every 4 hours not to exceed 5 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-55 mg oral tablet:
1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 600 mg-66 mg oral tablet, extended release:
1 to 2 tablets orally every 8 to 12 hours not to exceed 6 tablets daily.

Acetaminophen-phenyltoloxamine 635 mg-55 mg oral tablet and Acetaminophen-phenyltoloxamine 650 mg-60 mg oral tablet:
1/2 to 1 tablet orally every 6 hours not to exceed 4 tablets daily. Not to exceed 10 days use.

Usual Adult Dose for Pain

Acetaminophen-phenyltoloxamine 325 mg-30 mg oral tablet:
1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-50 mg oral tablet:
1/2 to 1 tablet orally every 4 hours not to exceed 5 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-55 mg oral tablet:
1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 600 mg-66 mg oral tablet, extended release:
1 to 2 tablets orally every 8 to 12 hours not to exceed 6 tablets daily.

Acetaminophen-phenyltoloxamine 635 mg-55 mg oral tablet and Acetaminophen-phenyltoloxamine 650 mg-60 mg oral tablet:
1/2 to 1 tablet orally every 6 hours not to exceed 4 tablets daily. Not to exceed 10 days use.

Usual Pediatric Dose for Influenza

Acetaminophen-phenyltoloxamine 325 mg-30 mg oral tablet:
12 years or older: 1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-50 mg oral tablet:
6 to 11 years: 1/2 tablet orally every 4 hours not to exceed 2.5 tablets daily.
12 years or older: 1/2 to 1 tablet orally every 4 hours not to exceed 5 tablets daily.

Acetaminophen-phenyltoloxamine 500 mg-55 mg oral tablet:
6 to 11 years: 1/2 to 1 tablet orally every 4 hours not to exceed 4 tablets daily.
12 years or older: 1 or 2 tablets orally every 4 hours not to exceed 8 tablets daily.

Acetaminophen-phenyltoloxamine 600 mg-66 mg oral tablet, extended release:
6 to 11 years: 1/2 to 1 tablet orally every 12 hours not to exceed 2 tablets daily.
12 years or older: 1 to 2 tablets orally every 8 to 12 hours not to exceed 6 tablets daily.

Acetaminophen-phenyltoloxamine 635 mg-55 mg oral tablet and Acetaminophen-phenyltoloxamine 650 mg-60 mg oral tablet:
6 to 11 years: 1/2 tablet orally every 6 hours not to exceed 2 tablets daily. Not to exceed 5 days use.
12 years or older: 1/2 to 1 tablet orally every 6 hours not to exceed 4 tablets daily. Not to exceed 10 days use.

Acetaminophen / phenyltoloxamine Breastfeeding Warnings

One small study has reported that following a 1000 mg dose of acetaminophen to nursing mothers, nursing infants receive less than 1.85% of the weight-adjusted maternal oral dose.

Acetaminophen is excreted into human milk in small concentrations. One case of a rash has been reported in a nursing infant. Acetaminophen is considered compatible with breast-feeding by the American Academy of Pediatrics. There are no data on the excretion of phenyltoloxamine into human milk.

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