Capacet Side Effects
Generic Name: acetaminophen / butalbital / caffeine
Note: This page contains information about the side effects of acetaminophen / butalbital / caffeine. Some of the dosage forms included on this document may not apply to the brand name Capacet.
Not all side effects for Capacet 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 / butalbital / caffeine: oral capsule, oral solution, oral tablet
In addition to its needed effects, some unwanted effects may be caused by acetaminophen / butalbital / caffeine. 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 / butalbital / caffeine:More common
- shortness of breath
- Abdominal or stomach pain
- black, tarry stools
- bleeding gums
- blistering, peeling, or loosening of the skin
- blood in the urine or stools
- blurred vision
- change in the frequency of urination or amount of urine
- difficulty with breathing
- difficulty with swallowing
- dry mouth
- fast heartbeat
- fast, pounding, or irregular heartbeat or pulse
- flushed or dry skin
- fruit-like breath odor
- increased hunger
- increased thirst
- increased urination
- joint or muscle pain
- loss of appetite
- nausea or vomiting
- pinpoint red spots on the skin
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- red skin lesions, often with a purple center
- red, irritated eyes
- shakiness in the legs, arms, hands, or feet
- shortness of breath
- skin rash
- sore throat
- sores, ulcers, or white spots in the mouth or on the lips
- swelling of the feet or lower legs
- tightness in the chest
- trembling or shaking of the hands or feet
- troubled breathing
- unexplained weight loss
- unusual bleeding or bruising
- unusual tiredness or weakness
If any of the following symptoms of overdose occur while taking acetaminophen / butalbital / caffeine, get emergency help immediately:Symptoms of overdose
- Confusion as to time, place, or person
- dark urine
- difficult or painful urination
- difficult or troubled breathing
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
- general feeling of discomfort or illness
- holding false beliefs that cannot be changed by fact
- increased sweating
- irregular, fast or slow, or shallow breathing
- light-colored stools
- loss of appetite
- pale or blue lips, fingernails, or skin
- sudden decrease in the amount of urine
- trouble sleeping
- unable to sleep
- unpleasant breath odor
- unusual excitement, nervousness, or restlessness
- vomiting of blood
- yellow eyes or skin
Some of the side effects that can occur with acetaminophen / butalbital / caffeine 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
- continuing ringing or buzzing or other unexplained noise in the ears
- excess air or gas in the stomach or intestines
- false or unusual sense of well-being
- full feeling
- hearing loss
- heavy eyelids
- high energy
- hot spells
- pain in the leg
- passing gas
- stuffy nose
- tingling sensation
For Healthcare Professionals
Applies to acetaminophen / butalbital / caffeine: oral capsule, oral liquid, oral tablet
Nervous system side effects including drowsiness, lightheadedness, dizziness, sedation, and an intoxicated feeling have been reported frequently from the use of butalbital. Headache and seizures have been reported infrequently. Mental confusion, excitement, or depression have also been reported due to either intolerance (primarily in elderly or debilitated patients) or due to an overdose of butalbital.
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.
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.
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.
Gastrointestinal side effects are rare with acetaminophen use, except in alcoholics and after overdose. Nausea, vomiting, and abdominal pain have been reported frequently with the use of butalbital. In clinical trials of caffeine citrate, five cases of necrotizing enterocolitis were reported among the 46 infants exposed to the caffeine citrate injection.
Renal side effects are rare with acetaminophen and include 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.
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.
Hypersensitivity side effects including anaphylaxis and fixed drug eruptions have been reported rarely in association with acetaminophen use.
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.
Dermatologic side effects including acetaminophen associated bullous erythema and purpura fulminans have been reported. Erythematous skin rashes associated with acetaminophen have been reported rarely. Acetaminophen has been associated with a risk of rare but potentially fatal serious skin reactions know as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP).
Respiratory side effects including dyspnea have been reported frequently with the use of butalbital. A case of acetaminophen-induced eosinophilic pneumonia has also been reported.
Cardiovascular side effects including several cases of hypotension have been reported following the administration of acetaminophen.
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.
Other side effects have included a positive association with fibrocystic breast disease. 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.
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