Acetaminophen, caffeine, and isometheptene

Avoid drinking alcohol. Alcohol may increase your risk of liver damage while taking acetaminophen.

Avoid coffee, tea cola, diet pills, energy drinks or other sources of caffeine while taking this medicine. They can add to the side effects of the caffeine in the medication.

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.

Other drugs may interact with acetaminophen, caffeine, and isometheptene, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Applies to acetaminophen / caffeine / isometheptene mucate: oral capsule, oral tablet

Hepatic

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]

Hepatic side effects including severe and sometimes fatal dose dependent hepatitis have been reported in alcoholic patients with the use of acetaminophen. 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]

General

General side effects including caffeinism have been reported. Caffeinism is a syndrome characterized by anxiety, restlessness, and sleep disorders (similar to anxiety states). Caffeine may cause anxiety and panic in panic disorder patients and may aggravate PMS.[Ref]

Consumption of higher doses of caffeine (>600 mg/day) has been reported to have lead to caffeinism. It has also been reported that chronic, heavy caffeine ingestion may be associated with depression.[Ref]

Other

Other side effects including an increased incidence of fibrocystic breast disease have been reported with caffeine use.[Ref]

In one study of the effects of caffeine, 634 women with fibrocystic breast disease (compared to 1066 women without the disease), the occurrence of fibrocystic breast disease was positively associated with average daily consumption of caffeine. Women who consumed 31 to 250 mg/day of caffeine were reported to have a 1.5 times increase in odds to have the disease. Women who consumed over 500 mg/day of caffeine were reported to have a 2.3 times increase in odds.[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 have been rare with the use of acetaminophen, except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with the use of acetaminophen. In clinical trials of caffeine citrate, five cases of necrotizing enterocolitis were reported among the 46 infants exposed to the caffeine citrate injection.[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. 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, but are rare. Acetaminophen associated bullous erythema and purpura fulminans have also been reported. Acetaminophen has been associated with a risk of rare but potentially fatal serious skin reactions know as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP).[Ref]

Respiratory

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

Cardiovascular

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]

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

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

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