Acetaminophen and chlorpheniramine Side Effects

Please note - some side effects for Acetaminophen and chlorpheniramine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Side Effects by Body System - for Healthcare Professionals

Applies to: 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.

Hepatic side effects of acetaminophen have included severe and sometimes fatal dose dependent hepatitis 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.

Gastrointestinal

Gastrointestinal side effects of acetaminophen have been rare, except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with the use of acetaminophen.

Gastrointestinal side effects of chlorpheniramine have included dry mouth and constipation in up to one-third of treated patients.

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.

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.

Renal side effects of acetaminophen 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.

Hypersensitivity

Hypersensitivity side effects of acetaminophen have included anaphylaxis and fixed drug eruptions.

Hematologic

Hematologic side effects of acetaminophen have included rare cases of thrombocytopenia. 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 of chlorpheniramine have included bone marrow suppression, thrombocytopenia, and aplastic anemia.

A fatal case of agranulocytosis has been reported in a patient taking chlorpheniramine, pseudoephedrine, acetaminophen, dextromethorphan, phenylpropanolamine, and aspirin. Chlorpheniramine was felt to be the cause.

Dermatologic

Dermatologic side effects of acetaminophen have included erythematous skin rashes. Bullous erythema and purpura fulminans have also been reported.

Respiratory

Respiratory side effects of acetaminophen have included a case of eosinophilic pneumonia.

Cardiovascular

Cardiovascular side effects of acetaminophen have included two cases of hypotension.

Cardiovascular side effects of chlorpheniramine have included hypotension, tachycardia, and palpitations.

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.

Metabolic

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.

Metabolic side effects of acetaminophen have included metabolic acidosis following a massive overdose.

Nervous system

Few cases of dyskinesias and tremors, often of the face, have been reported in patients whose chronic use of chlorpheniramine extended over a period of 3 to 10 years. Some of these cases were only partially relieved by discontinuation of the drug. Haloperidol was successful in relieving symptoms.

Nervous system side effects of chlorpheniramine have included depression resulting in drowsiness in 75% or more of treated patients. Dyskinesias have rarely been reported following chronic use of chlorpheniramine.

Ocular

Ocular side effects of chlorpheniramine have included blurred vision, diplopia, and dry eyes due to anticholinergic effects.

Genitourinary

Genitourinary side effects of chlorpheniramine have included dysuria, urinary hesitancy, and decreased urine flow.

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