Medication Guide App

Balacet Side Effects

Generic Name: acetaminophen / propoxyphene

Note: This page contains information about the side effects of acetaminophen / propoxyphene. Some of the dosage forms included on this document may not apply to the brand name Balacet.

Not all side effects for Balacet may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to acetaminophen / propoxyphene: oral tablet

In addition to its needed effects, some unwanted effects may be caused by acetaminophen / propoxyphene. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking acetaminophen / propoxyphene:

  • Abdominal or stomach pain
  • chills
  • clay-colored stools
  • dark urine
  • dizziness
  • fever
  • headache
  • itching
  • loss of appetite
  • nausea
  • rash
  • unpleasant breath odor
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin
Incidence not known
  • Bloating
  • bloody or black, tarry stools
  • bloody or cloudy urine
  • change in consciousness
  • chest pain or discomfort
  • confusion
  • cough
  • decreased urine output
  • difficult or troubled breathing
  • dilated neck veins
  • drowsiness
  • extreme fatigue
  • fainting
  • fast, slow, pounding, or irregular heartbeat or pulse
  • fever with or without chills
  • general feeling of discomfort or illness
  • hives
  • hoarseness
  • irregular, fast, slow, or shallow breathing
  • itching
  • joint pain, stiffness, or swelling
  • light-colored stools
  • loss of consciousness
  • low blood pressure or pulse
  • muscle aches and pains
  • muscle tremors
  • pain or discomfort in the arms, jaw, back, or neck
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pale or blue lips, fingernails, or skin
  • rapid, deep breathing
  • redness of the skin
  • restlessness
  • right upper stomach pain and fullness
  • runny nose
  • severe stomach pain
  • shakiness and unsteady walk
  • shivering
  • shortness of breath
  • sore throat
  • stomach cramps
  • sudden decrease in the amount of urine
  • sweating
  • swelling of the eyelids, face, fingers, lips, hands, lower legs, or feet
  • thoughts of suicide
  • tightness in the chest
  • trouble sleeping
  • troubled breathing or swallowing
  • unconsciousness
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • very slow breathing
  • very slow heartbeat
  • vomiting of blood or material that looks like coffee grounds
  • weight gain
  • wheezing

If any of the following symptoms of overdose occur while taking acetaminophen / propoxyphene, get emergency help immediately:

Symptoms of overdose
  • Agitation
  • bluish color of the fingernails, lips, skin, palms, or nail beds
  • convulsion
  • coughing that sometimes produces a pink frothy sputum
  • decreased awareness or responsiveness
  • depression
  • difficult, fast, or noisy breathing, sometimes with wheezing
  • dilated pupils
  • hostility
  • increased sweating
  • irritability
  • lethargy
  • muscle tremors
  • muscle twitching
  • pale skin
  • pounding or rapid pulse
  • rapid weight gain
  • rapid, deep breathing
  • severe sleepiness
  • sleepiness or unusual drowsiness
  • slow to respond
  • slurred speech
  • weight loss

Some of the side effects that can occur with acetaminophen / propoxyphene may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Relaxed and calm feeling
Incidence not known
  • Abnormal behavior
  • blurred or loss of vision
  • constipation
  • diarrhea
  • disturbed color perception
  • double vision
  • false or unusual sense of well-being
  • halos around lights
  • indigestion
  • muscular pain, tenderness, wasting, or weakness
  • night blindness
  • nightmares or unusually vivid dreams
  • overbright appearance of lights
  • seeing, hearing, or feeling things that are not there
  • swelling of the eye
  • tunnel vision

For Healthcare Professionals

Applies to acetaminophen / propoxyphene: oral tablet

Nervous system

Nervous system side effects of propoxyphene have included dizziness, sedation, stupor, delirium, somnolence, ataxia, coma, syncope, and respiratory depression. The sedative effects of propoxyphene have been associated with a 60% increased risk of hip fracture in elderly patients.


Other side effects including propoxyphene dependence have been reported (although the abuse liability of propoxyphene is less than that of some other narcotic analgesics). Withdrawal symptoms (after either abrupt cessation or fast tapering) have been reported to include agitation, restlessness, anxiety, insomnia, tremor, tachycardia, hallucinations, psychosis, abdominal cramps, vomiting, sweating, and seizures.

Drug toxicity, multiple drug overdose, and narcotic overdose have also been reported with propoxyphene.

Sensorineural deafness has been reported following chronic abuse and/or large doses of propoxyphene-containing compounds. Optic atrophy has been reported following overdose.


Gastrointestinal side effects of acetaminophen are rare, except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with acetaminophen use. Nausea, vomiting, and constipation are relatively common effects of propoxyphene. Gastrointestinal bleeding and acute pancreatitis have also been reported with the use of propoxyphene.

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.

Elevated liver function tests, jaundice and hepatotoxicity have been reported in association with propoxyphene.

A case of ischemic colitis has been reported following an overdose of propoxyphene which was complicated by severe hypotension.


Cardiovascular side effects of propoxyphene have included arrhythmia, bradycardia, cardiac/respiratory arrest, congestive arrest, congestive heart failure (CHF), tachycardia, myocardial infarction (MI), hypotension, decreased blood pressure, elevated heart rate, abnormal heart rate, and dizziness. A variety of arrhythmias (including heart block) have been reported most often in association with overdose.

Some of the cardiotoxic effects reported in association with propoxyphene may be attributable to its major active metabolite, norpropoxyphene.


Renal side effects of acetaminophen have been rare and have included acute tubular necrosis and interstitial nephritis. Cases of severe hypoglycemia have been reported in patients with chronic renal failure who received propoxyphene.

Acute tubular necrosis associated with acetaminophen usually occurs in conjunction with liver failure, but has been observed as an isolated finding in rare cases. Adverse acetaminophen renal effects are most often observed after overdose, after chronic abuse (often with multiple analgesics), or in association with acetaminophen-related hepatotoxicity. A possible increase in the risk of renal cell carcinoma has been associated with chronic acetaminophen use as well.

A single case of nephrogenic diabetes insipidus has been reported following overdose of propoxyphene (however, other causes of diabetes insipidus in that patient were not rigorously excluded).

The adverse effects of propoxyphene may be more likely and more severe in patients with renal insufficiency.


Hypersensitivity side effects to acetaminophen have been reported rarely.

Hypersensitivity side effects to propoxyphene have also been reported.


Genitourinary side effects have included a case of retroperitoneal fibrosis in association with propoxyphene therapy.


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. Cases of hemolytic anemia, pancytopenia, and disseminated intravascular coagulation after administration (or abuse) of propoxyphene-containing compounds have been reported rarely.


General erythematous skin rashes associated with acetaminophen have been reported, but are rare. A rare case of bullous erythema associated with acetaminophen has been reported.

Dermatologic side effects including rashes have been reported in association with both propoxyphene and acetaminophen. Itch has also been reported with the use of propoxyphene.


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

Respiratory side effects including dyspnea have been reported with the use of propoxyphene.


Musculoskeletal side effects including myopathy and rhabdomyolysis have been reported after chronic oral use. Fibrous myopathy has also been reported in propoxyphene-abusing patients who administer the drug via intramuscular injection.


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.

The adverse effects of acetaminophen-propoxyphene may be more likely and more severe in patients with liver disease.

Hepatic side effects of acetaminophen including severe and sometimes fatal dose dependent hepatitis have been reported 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.

Hepatic side effects of propoxyphene have included elevated liver function tests, jaundice, hepatic steatosis, hepatomegaly, hepatocellular injury, and hepatotoxicity.


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 including metabolic acidosis have been reported following a massive overdose of acetaminophen.

Metabolic side effects including metabolic acidosis have been reported with the use of propoxyphene. Cases of severe hypoglycemia have been reported in patients with chronic renal failure.


Ocular side effects including eye swelling and vision blurred have been reported with the use of propoxyphene.


General side effects including drug tolerance and influenza type illness have been reported with the use of propoxyphene.


Psychiatric side effects including abnormal behavior, confusional state, hallucinations, and mental status change have been reported with the use of propoxyphene.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.