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(Butalbital and acetaminophen) Tablets 50 mg/650 mg


Butalbital and acetaminophen is supplied in tablet form for oral administration:

Butalbital (5-allyl-5-isobutylbarbituric acid), a slightly bitter, white, odorless, crystalline powder, is a short to intermediate-acting barbiturate. It has the following structural formula:

Butalbital Structural Formula Illustration

C11H16N2O3       MW = 224.26

Acetaminophen (4-hydroxyacetanilide), a slightly bitter, white, odorless, crystalline powder, is a non-opiate, non-salicylate analgesic and antipyretic. It has the following structural formula:

Acetaminophen Structural Formula Illustration

C8H9NO2       MW = 151.16

Each Cephadyn Tablet contains:

Butalbital ............... 50 mg

(Warning: May be habit-forming.)

Acetaminophen .... 650 mg

In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, crospovidone, microcrystalline cellulose, povidone, pregelatinized starch, stearic acid with FD&C Blue #1 Lake as coloring.

What are the possible side effects of acetaminophen and butalbital?

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...

Read All Potential Side Effects and See Pictures of Cephadyn »

Last reviewed on RxList: 8/11/2011
This monograph has been modified to include the generic and brand name in many instances.

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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