Lobac Side Effects
Generic name: acetaminophen / phenyltoloxamine / salicylamide
Medically reviewed by Drugs.com. Last updated on Aug 13, 2022.
Note: This document contains side effect information about acetaminophen / phenyltoloxamine / salicylamide. Some dosage forms listed on this page may not apply to the brand name Lobac.
Applies to acetaminophen/phenyltoloxamine/salicylamide: oral capsule.
Serious side effects of Lobac
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Signs of bleeding like throwing up or coughing up blood; vomit that looks like coffee grounds; blood in the urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a cause or that get bigger; or bleeding you cannot stop.
- Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
- A fast heartbeat.
- A heartbeat that does not feel normal.
- Very bad dizziness or passing out.
- Ringing in ears.
- Not able to pass urine or change in how much urine is passed.
- Change in balance.
- Not able to focus.
- Blurred eyesight.
- A very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause very bad health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
Other side effects of Lobac
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Feeling sleepy.
- Feeling nervous and excitable.
- Upset stomach or throwing up.
- Dry mouth.
- Not hungry.
- Trouble sleeping.
- Muscle weakness.
- Stomach cramps.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
For Healthcare Professionals
Applies to acetaminophen/phenyltoloxamine/salicylamide: oral capsule, oral tablet.
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.[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.
Gastrointestinal side effects are rare with acetaminophen use, except in alcoholics and after overdose. Gastric distress, diarrhea, intestinal cramps, dryness of the mouth, throat, and nose, xerostomia, and nausea have been reported with the use of phenyltoloxamine. Nausea, vomiting, heartburn, anorexia, and diarrhea have been reported with the use of salicylamide.[Ref]
Renal side effects have been rare with acetaminophen and have included acute tubular necrosis and interstitial nephritis. 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 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.
One 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.
However, a recent cohort study of analgesia use of initially healthy men concluded that moderate use of analgesics including acetaminophen was not associated with increased risk of renal disease.[Ref]
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 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. Urticaria has been reported with the use of phenyltoloxamine. Flushing, sweating, and rash has been reported with the use of salicylamide.[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]
Cardiovascular side effects including two cases of hypotension have been reported following the administration of acetaminophen. Hypotension has also been reported with the use of phenyltoloxamine.[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]
Nervous system side effects including drowsiness and convulsions have been reported with the use of phenyltoloxamine. Dizziness, drowsiness, lightheadedness, faintness, and headache have been reported with the use of salicylamide.[Ref]
Other side effects including disturbed coordination, inability to concentrate, dizziness, insomnia, tremors, and nervousness have been reported with the use of phenyltoloxamine. Mild salicylism has been reported with the use of salicylamide.[Ref]
Musculoskeletal side effects including muscular weakness have been reported with the use of phenyltoloxamine.[Ref]
Ocular side effects including blurred vision have been reported with the use of phenyltoloxamine.[Ref]
More about Lobac (acetaminophen / phenyltoloxamine / salicylamide)
Related treatment guides
1. Zimmerman HJ, Maddrey WC "Acetaminophen (paracetamol) hepatotoxicity with regular intake of alcohol: analysis of instances of therapeutic misadventure." Hepatology 22 (1995): 767-73
2. 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
3. Singer AJ, Carracio TR, Mofenson HC "The temporal profile of increased transaminase levels in patients with acetaminophen-induced liver dysfunction." Ann Emerg Med 26 (1995): 49-53
4. "Product Information. Ed-Flex (acetaminophen / phenyltoloxamine / salicylamide)." Edwards Pharmaceuticals Inc (2022):
5. Eguia L, Materson BJ "Acetaminophen-related acute renal failure without fulminant liver failure." Pharmacotherapy 17 (1997): 363-70
6. Kawada A, Hiruma M, Noguchi H, Ishibashi A "Fixed drug eruption induced by acetaminophen in a 12-year-old girl." Int J Dermatol 35 (1996): 148-9
7. Halevi A, BenAmitai D, Garty BZ "Toxic epidermal necrolysis associated with acetaminophen ingestion." Ann Pharmacother 34 (2000): 32-4
8. Filipe PL, Freitas JP, Decastro JC, Silva R "Drug eruption induced by acetaminophen in infectious mononucleosis." Int J Dermatol 34 (1995): 220-1
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
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.