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Last reviewed on RxList: 11/30/2016
Cephadyn Side Effects Center

Last reviewed on RxList 4/19/2016

Cephadyn (butalbital and acetaminophen) is a combination of a barbiturate and a pain reliever and fever reducer used to treat tension headaches. Cephadyn is not for treating headaches that come and go. Common side effects of Cephadyn include:

  • headache
  • dizziness
  • drowsiness
  • shaky feeling
  • drunk feeling
  • vomiting
  • constipation
  • heartburn
  • trouble swallowing
  • numbness or tingly feeling
  • dry mouth
  • sweating or urinating more than usual
  • leg pain
  • tired muscles
  • stuffy nose
  • ear pain
  • ringing in your ears, or
  • itching

The dose of Cephadyn is one tablet every four hours as needed. Total daily dosage should not exceed 6 tablets. Cephadyn may interact with MAO inhibitors, cold or allergy medicine, sedatives, narcotics, sleeping pills, muscle relaxers, and medicine for seizures, depression or anxiety. Tell your doctor all medications and supplements you use. During pregnancy, Cephadyn should be used only if prescribed. This drug can cause seizures in a newborn if the mother takes the medication late in pregnancy. Tell your doctor if you are pregnant or plan to become pregnant while using Cephadyn. This medication passes into breast milk and may harm a nursing baby. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Our Cephadyn (butalbital and acetaminophen) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Cephadyn Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • fast or pounding heart rate, feeling short of breath;
  • feeling like you might pass out;
  • confusion, depression;
  • feeling restless, excited, or agitated;
  • seizure (convulsions); or
  • nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects include:

  • headache, dizziness, drowsiness, shaky feeling;
  • drunk feeling;
  • vomiting, constipation;
  • heartburn, trouble swallowing;
  • numbness or tingly feeling;
  • dry mouth;
  • sweating or urinating more than usual;
  • leg pain, tired muscles;
  • stuffy nose, ear pain, ringing in your ears; or
  • mild itching.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Cephadyn (butalbital and acetaminophen)

Cephadyn Professional Information


Frequently Observed

The most frequently reported adverse reactions are drowsiness, lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, abdominal pain, and intoxicated feeling.

Infrequently Observed

All adverse events tabulated below are classified as infrequent.

Central Nervous System

headache, shaky feeling, tingling, agitation, fainting, fatigue, heavy eyelids, high energy, hot spells, numbness, sluggishness, seizure. Mental confusion, excitement or depression can also occur due to intolerance, particularly in elderly or debilitated patients, or due to overdosage of butalbital.

Autonomic Nervous System: dry mouth, hyperhidrosis.

Gastrointestinal: difficulty swallowing, heartburn, flatulence, constipation.

Cardiovascular: tachycardia.

Musculoskeletal: leg pain, muscle fatigue.

Genitourinary: diuresis.

Miscellaneous: pruritus, fever, earache, nasal congestion, tinnitus, euphoria, allergic reactions.

Several cases of dermatological reactions, including toxic epidermal necrolysis and erythema multiforme, have been reported.

The following adverse drug events may be borne in mind as potential effects of the components of this product. Potential effects of high dosage are listed in the OVERDOSAGE section.

Acetaminophen: allergic reactions, rash, thrombocytopenia, agranulocytosis.

Drug abuse and depedence

Abuse and Dependence


Barbiturates may be habit-forming: Tolerance, psychological dependence, and physical dependence may occur especially following prolonged use of high doses of barbiturates. The average daily dose for the barbiturate addict is usually about 1500 mg. As tolerance to barbiturates develops, the amount needed to maintain the same level of intoxication increases; tolerance to a fatal dosage, however, does not increase more than two-fold. As this occurs, the margin between an intoxication dosage and fatal dosage becomes smaller. The lethal dose of a barbiturate is far less if alcohol is also ingested. Major withdrawal symptoms (convulsions and delirium) may occur within 16 hours and last up to 5 days after abrupt cessation of these drugs. Intensity of withdrawal symptoms gradually declines over a period of approximately 15 days. Treatment of barbiturate dependence consists of cautious and gradual withdrawal of the drug. Barbiturate dependent patients can be withdrawn by using a number of different withdrawal regimens. One method involves initiating treatment at the patient's regular dosage level and gradually decreasing the daily dosage as tolerated by the patient.

Read the entire FDA prescribing information for Cephadyn (butalbital and acetaminophen)

Related Resources for Cephadyn

© Cephadyn Patient Information is supplied by Cerner Multum, Inc. and Cephadyn Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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