ConRx Pain Reliever Side Effects
Generic Name: acetaminophen / aspirin / caffeine
Note: This page contains information about the side effects of acetaminophen / aspirin / caffeine. Some of the dosage forms included on this document may not apply to the brand name ConRx Pain Reliever.
For the Consumer
Applies to acetaminophen / aspirin / caffeine: capsules, tablets
Other dosage forms:
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 / aspirin / caffeine:
Heartburn; nausea; upset stomach.
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; fainting; hearing loss; ringing in the ears; symptoms of liver problems (eg, dark urine, pale stools, persistent loss of appetite, right-upper stomach pain, yellowing of the skin or eyes); unusual tiredness.
For Healthcare Professionals
Applies to acetaminophen / aspirin / caffeine: oral powder for reconstitution, oral tablet
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 with the use of acetaminophen.
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 hepatotoxicity and hepatitis have been reported.
In alcoholic patients, severe and sometimes fatal dose dependent hepatitis has been reported with acetaminophen use. Hepatotoxicity has been increased during fasting.
Cases of aspirin induced hepatotoxicity and cholestatic hepatitis, particularly at high doses, have been reported rarely.[Ref]
Endoscopically identifiable gastric mucosal lesions occur in most patients who receive a single dose of aspirin. Clinically evident gastrointestinal bleeding has been reported in as many as 3% of treated elderly patients. Anorectal ulceration and rectal stenosis have been reported in patients who abuse aspirin containing rectal suppositories. One case controlled study has suggested that an association between aspirin (and other NSAID) consumption and appendicitis may exist.[Ref]
Gastrointestinal side effects have been common and have included epigastric distress (in as many as 83% of patients treated with regular aspirin), abdominal discomfort or pain, endoscopically identifiable gastric mucosal lesions, nausea, and vomiting. More serious gastrointestinal effects include hemorrhage, peptic ulcers, perforation, and esophageal ulcerations.
In clinical trials of caffeine citrate, five cases of necrotizing enterocolitis were reported among the 46 infants exposed to the caffeine citrate injection.
Gastrointestinal side effects have been rare with the use of acetaminophen, except in alcoholics and after overdose.[Ref]
General side effects including caffeinism have been reported. Consumption of higher doses of caffeine (>600 mg/day) has been reported to have lead to caffeinism. Caffeinism is a syndrome characterized by anxiety, restlessness, and sleep disorders (similar to anxiety states). It has also been reported that chronic, heavy caffeine ingestion may be associated with depression. Caffeine may cause anxiety and panic in panic disorder patients and may aggravate PMS.
In general, many side effects noted with aspirin use are dose-related.[Ref]
The mechanism of an aspirin induced decrease in renal function may be related to inhibition of renal prostaglandin synthesis with consequent decreases in renal blood flow. Vasodilating renal prostaglandins may be particularly important in patients who exhibit arterial underfilling (i.e. heart failure, cirrhosis). The administration of high doses of NSAIDs to such patients has produced acute renal failure in rare instances.
Acetaminophen: 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 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 of aspirin have included reduction in glomerular filtration rate (particularly in patients who are sodium restricted or who exhibit diminished effective arterial blood volume, such as patients with advanced heart failure or cirrhosis), interstitial nephritis, papillary necrosis, elevations in serum creatinine, elevations in blood urea nitrogen, proteinuria, hematuria, and renal failure.
Renal side effects have been rare with acetaminophen use 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 side effects of aspirin have included bronchospasm, rhinitis, conjunctivitis, urticaria, angioedema, and anaphylaxis. Approximately 10% to 30% of asthmatics are aspirin sensitive (with the clinical triad of aspirin sensitivity, bronchial asthma, and nasal polyps).
Hypersensitivity reactions such as anaphylaxis and fixed drug eruptions have rarely been reported in association with acetaminophen use.[Ref]
The mechanism of aspirin induced hypersensitivity may be related to an up-regulation of the 5-lipoxygenase pathway of arachidonic acid metabolism with a resulting increase in the products of 5-lipoxygenase (such as leukotrienes).[Ref]
Hematologic side effects of aspirin (in addition to predictable antiplatelet effects which may result in hemorrhage) have included increased blood fibrinolytic activity. In addition, hypoprothrombinemia, thrombocytopenia, thrombocyturia, megaloblastic anemia, and pancytopenia have been reported rarely. Aplastic anemia has also been reported.
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 from the use of aspirin including Stevens-Johnson syndrome and a lichenoid eruption have been reported rarely.
Dermatologic side effects associated with acetaminophen includes the 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). Erythematous skin rashes associated with acetaminophen have been reported, but are rare. Acetaminophen associated bullous erythema and purpura fulminans have been reported.[Ref]
Respiratory side effects including hyperpnea, pulmonary edema, and tachypnea have occurred in patients receiving aspirin.
A case of acetaminophen induced eosinophilic pneumonia has been reported.[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 of aspirin have been reported rarely and have included salicylate induced variant angina, ventricular ectopy, conduction abnormalities, and hypotension, particularly during salicylate toxicity.
Several cases of hypotension have been reported following the administration of acetaminophen.[Ref]
Metabolic side effects of aspirin have included dehydration and hyperkalemia. Respiratory alkalosis and metabolic acidosis, particularly during salicylate toxicity, have been reported. A case of hypoglycemia has also been reported in a patient on hemodialysis.[Ref]
Nervous system side effects in patients receiving aspirin have included agitation, cerebral edema, coma, confusion, dizziness, headache, cranial hemorrhage, lethargy, and seizures. Some investigators have reported that modest doses may result in decreased frequency selectivity and may therefore impair hearing performance, particularly in the setting of background noise.[Ref]
Regarding the use of aspirin, some investigators have suggested that tinnitus may be a less reliable indicator of salicylate toxicity than previously believed. Patients with high frequency hearing loss may have difficulty perceiving tinnitus. In a study of rheumatoid arthritis patients, those with tinnitus had no greater salicylate levels than those without tinnitus. Elderly patients may be less likely to perceive tinnitus than younger patients.[Ref]
Other side effect have also been reported. 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.
Reye's syndrome, although rare, has been associated with aspirin use in children with an acute viral illness. Reye's syndrome has also been reported even more rarely in adults.
Prolonged labor and pregnancy, decreased infant birth weight and stillborn births, antepartum and postpartum bleeding have occurred due to aspirin use by women during the third trimester of pregnancy.[Ref]
Reye's syndrome typically involves vomiting, neurologic dysfunction, and hepatic dysfunction during or shortly after an acute viral infection.[Ref]
Musculoskeletal side effects including rhabdomyolysis have occurred in patients receiving aspirin.[Ref]
Endocrine side effects of aspirin use have included hypoglycemia and hyperglycemia.[Ref]
Ocular side effects including cases of localized periorbital edema have been reported rarely in patients receiving aspirin.[Ref]
Oncologic side effects have been reported. Several epidemiologic studies have suggested that chronic aspirin use may decrease the risk of large bowel neoplasms. However, other studies have not found this beneficial effect.[Ref]
1. He J, Whelton PK, Vu B, Klag MJ "Aspirin and risk of hemorrhagic stroke: a meta-analysis of randomized controlled trials." JAMA 280 (1998): 1930-35
2. Petty GW, Brown RD, Whisnant JP, Sicks JD, O'Fallon WM, Wiebers DO "Frequency of major complications of aspirin, warfarin, and intravenous heparin for secondary stroke prevention: a population study." Ann Intern Med 130 (1999): 14-22
3. Lanas A, Serrano P, Bajador E, Esteva F, Benito R, Sainz R "Evidence of aspirin use in both upper and lower gastrointestinal perforation." Gastroenterology 112 (1997): 683-9
4. Boissel JP "Individualizing aspirin therapy for prevention of cardiovascular events." JAMA 280 (1998): 1949-50
5. 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
6. Zimmerman HJ, Maddrey WC "Acetaminophen (paracetamol) hepatotoxicity with regular intake of alcohol: analysis of instances of therapeutic misadventure." Hepatology 22 (1995): 767-73
7. Dickinson JP, Prentice CRM "Aspirin: benefit and risk in thromboprophylaxis." Qjm Mon J Assoc Physician 91 (1998): 523-38
8. Lee WM "Medical progress: drug-induced hepatotoxicity." N Engl J Med 333 (1995): 1118-27
9. "Multum Information Services, Inc. Expert Review Panel"
10. Sawynok J "Pharmacological rationale for the clinical use of caffeine." Drugs 49 (1995): 37-50
11. "Product Information. Bayer aspirin (aspirin)." Bayer, West Haven, CT.
12. Clementz GL, Dailey JW "Psychotropic effects of caffeine." Am Fam Physician 37 (1988): 167-72
13. Perneger TV, Whelton PK, Klag MJ "Risk of kidney failure associated with the use of acetaminophen, aspirin, and nonsteroidal antiinflammatory drugs." N Engl J Med 331 (1994): 1675-79
14. 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
15. Shoenfeld Y, Shaklai M, Livni E, Pinkhas J "Thrombocytopenia from acetaminophen." N Engl J Med 303 (1980): 47
16. Filipe PL, Freitas JP, Decastro JC, Silva R "Drug eruption induced by acetaminophen in infectious mononucleosis." Int J Dermatol 34 (1995): 220-1
17. Brown G "Acetaminophen-induced hypotension." Heart Lung 25 (1996): 137-40
18. Boyle CA, Berkowitz GS, LiVolsi VA, Ort S, Merino MJ, White C, Kelsey JL "Caffeine consumption and fibrocystic breast disease: a case-control epidemiologic study." J Natl Cancer Inst 72 (1984): 1015-9
Not all side effects for ConRx Pain Reliever may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
More about ConRx Pain Reliever (acetaminophen / aspirin / caffeine)
- Side Effects
- During Pregnancy
- Dosage Information
- Drug Interactions
- 0 Reviews – Add your own review/rating
- Drug class: analgesic combinations
Related treatment guides
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. Drugs.com 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.