Acetaminophen / phenylephrine Side Effects
For the Consumer
Applies to acetaminophen / phenylephrine: capsules, tablets
Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur while taking acetaminophen / phenylephrine:
Constipation; diarrhea; dizziness; drowsiness; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); dark urine; difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; mood or mental changes; seizures; severe dizziness, lightheadedness, or headache; severe drowsiness; stomach pain; tremor; vision changes; yellowing of skin or eyes.
For Healthcare Professionals
Applies to acetaminophen / phenylephrine: oral capsule, oral powder for reconstitution, oral tablet, oral tablet chewable, oral tablet effervescent
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 side effects with acetaminophen are rare except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with the use of acetaminophen.
Gastrointestinal side effects of phenylephrine have included nausea.[Ref]
One study has suggested that acetaminophen may precipitate acute biliary pain and cholestasis. The mechanism for this side effect may be related to inhibition of prostaglandins and alterations in the regulation of the sphincter of Oddi.[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]
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]
Hypersensitivity side effects including anaphylaxis and fixed drug eruptions have been reported rarely in association with acetaminophen use.[Ref]
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.[Ref]
Dermatologic side effects including erythematous skin rashes associated with acetaminophen have been reported, but are rare. Acetaminophen associated bullous erythema and purpura fulminans have been reported. One case of toxic epidermal necrolysis associated with acetaminophen administered to a pediatric patient has been reported. Acetaminophen has been associated with a risk of rare but potentially fatal serious skin reactions known as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP).[Ref]
Respiratory side effects have included a case of eosinophilic pneumonia which has been associated with acetaminophen.
Respiratory side effects of phenylephrine have included respiratory difficulty.[Ref]
Two cases of 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 have included at least two cases of hypotension which have been reported following the administration of acetaminophen.
Cardiovascular side effects of phenylephrine have included palpitations, arrhythmias, and cardiovascular collapse with hypotension.[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]
Metabolic side effects including metabolic acidosis have been reported following a massive overdose of acetaminophen.[Ref]
Nervous system side effects of phenylephrine have included headache, dizziness, nervousness, restlessness, tremor, insomnia, convulsions, and central nervous system depression.[Ref]
Psychiatric side effects of phenylephrine have included hallucinations, fear, and anxiety.[Ref]
Genitourinary side effects of phenylephrine have included dysuria.[Ref]
General side effects of phenylephrine have included pallor and weakness.[Ref]
1. Gursoy M, Haznedaroglu IC, Celik I, Sayinalp N, Ozcebe OI, Dundar SV "Agranulocytosis, plasmacytosis, and thrombocytosis followed by a leukemoid reaction due to acute acetaminophen toxicity." Ann Pharmacother 30 (1996): 762-5
2. Bolesta S, Haber SL "Hepatotoxicity associated with chronic acetaminophen administration in patients without risk factors." Ann Pharmacother 36 (2002): 331-3
3. "Product Information. Ah-Chew D (phenylephrine)." WE Pharmaceuticals Inc, Ramona, CA.
4. Lee WM "Medical progress: drug-induced hepatotoxicity." N Engl J Med 333 (1995): 1118-27
5. Eguia L, Materson BJ "Acetaminophen-related acute renal failure without fulminant liver failure." Pharmacotherapy 17 (1997): 363-70
6. Halevi A, BenAmitai D, Garty BZ "Toxic epidermal necrolysis associated with acetaminophen ingestion." Ann Pharmacother 34 (2000): 32-4
7. Bougie DW, Benito AI, Sanchez-Abarca LI, Torres R, Birenbaum J, Aster RH "Acute thrombocytopenia caused by sensitivity to the glucuronide conjugate of acetaminophen." Blood 109 (2007): 3608-9
8. Shoenfeld Y, Shaklai M, Livni E, Pinkhas J "Thrombocytopenia from acetaminophen." N Engl J Med 303 (1980): 47
9. Kondo K, Inoue Y, Hamada H, Yokoyama A, Kohno N, Hiwada K "Acetaminophen-induced eosinophilic pneumonia." Chest 104 (1993): 291-2
10. Brown G "Acetaminophen-induced hypotension." Heart Lung 25 (1996): 137-40
11. Koulouris Z, Tierney MG, Jones G "Metabolic acidosis and coma following a severe acetaminophen overdose." Ann Pharmacother 33 (1999): 1191-4
12. "Product Information. Alka-Seltzer Plus Cold and Sinus (acetaminophen-phenylephrine)." Bayer, West Haven, CT.
Not all side effects for acetaminophen / phenylephrine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
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