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Dichloralphenazone is a general sedative-hypnotic that slows central nervous system (CNS) function, causing relaxation and pain relief. It is primarily indicated as a component of a drug that is used in the treatment of tension (muscle contraction) and vascular (migraine) headaches. Additional uses for dichloralphenazone include sedation and pain relief, and treatment for symptoms associated with insomnia.


The combination medication, including isometheptene, dichloralphenazone, and acetaminophen, is used to treat tension and vascular headaches . Although the combination does not prevent the occurrence of tension headaches or migraines, isometheptene, dichloralphena-zone, and acetaminophen act to relieve pain at its onset. The combination also relieves some symptoms associated with migraine such as altered vision and sensitivity to light and sound.


Dichloralphenazone is not indicated for routine use. The medication should be taken only at the onset of pain, tension headache symptoms, or at the first warning signs of migraine.

Recommended dosage

Dichloralphenazone is most commonly available in capsule form, and is prescribed by physicians in varying dosages. The usual dose for adults is one to two capsules. Under the supervision of a physician, treatment that includes dichloralphenazone may be appropriate for some children.

A double dose of dichloralphenazone should not be taken. If the first dose fails to relieve pain or symptoms associated with tension headache or migraine, the patient should follow instructions provided by the prescribing physician for taking supplemental doses every few hours. If pain persists for several days, this medication should not be taken without consulting the prescribing physician.


Dichaloralphenazone may cause drowsiness and sleepiness for several hours. Extreme caution should be used when driving or operating machinery.

A physician should be consulted before taking any form of dichloralphenazone with certain non-prescription medications. Patients taking dichloralphenazone should avoid alcohol and CNS depressants, including medicines that can make one drowsy or less alert such as antihistimines, sleep medications, and some pain medications. These medicines can exacerbate the side effects of dichloraphenazone.

Dichloralphenazone may not be suitable for persons with a history of seizures , stroke , asthma or other chronic lung diseases, liver disease, kidney disease, mental illness, high blood pressure, angina (chest pain), irregular heartbeats, or other heart problems. Patients should notify their physician if they smoke, consume a large amount of alcohol, have a history of drug use, are nursing, pregnant, or plan to become pregnant. The effect of dichloralphenazone during pregnancy has not been fully established. Patients who become pregnant while taking dichloralphenazone should contact their physician.

Side effects

Patients and their physicians should weigh the risks and benefits of dichloralphenazone before beginning treatment, as some forms of dichloralphenazone may be habit forming. Most patients tolerate combination medications with dichloralphenazone well. However, some people may experience a variety of mild to moderate side effects. A few possible side effects such as headache, upset stomach, and nausea mirror symptoms associated with tension headaches and migraine. Common side effects that do not usually require medical attention include:

  • dizziness or unsteadiness
  • sleepiness or drowsiness
  • feeling of warmth or heaviness
  • increased sweating
  • flushing
  • tingling feeling
  • diarrhea

Other, less common side effects of dichloralphenazone could indicate a potentially serious condition. The sudden onset of some severe side effects may indicate an allergic reaction. If any of the following serious side effects occur, the prescribing physician should be contacted immediately:

  • rash, lumps, or hives
  • redness or swelling of the face, lips, or eyelids
  • change in vision
  • wheezing and difficulty breathing
  • chest pain or tightness in the chest
  • irregular heartbeat
  • faintness or loss of consciousness sudden or severe stomach pain
  • persistent fever


Dichloralphenazone may have negative interactions with antibiotics, antidepressants, anticoagulants, anti-epileptic drugs (AEDs), anticonvulsants , antihistimines, asthma medications, and monoamine oxidase inhibitors (MAOIs). Patients should not take dichloralphenazone for several weeks after stopping treatment with MAOIs.

Dichloralphenazone should not be used in conjunction with other migraine treatment medications unless otherwise directed by a physician.



Lang, Susan. Headache Help: A Complete Guide to Understanding Headaches and the Medications That Relieve ThemFully Revised and Updated. New York: Houghton Mifflin, 2000.

Robbins, Lawrence. Management of Headache and Headache Medications. New York: Springer Verlag, 2000.


"Isometheptene, Dichloralphenazone, and Acetaminophen (Systemic)." Medline Plus Drug Information. National Library of Medicine. May 6, 2004 (May 22, 2004). <http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202306.html>.


ACHE (American Council for Headache Education). 19 Mantua Road, Mt. Royal, NJ 08601. (856) 423-0258. <http://www.achenet.org>.

National Headache Foundation. 428 W. St. James Place, 2nd Floor, Chicago, IL 60614. (703) 739-9384 or (888) NHF-5552. <http://www.headaches.org>.

Migraine Awareness Group. 113 South Saint Asaph Street, Suite 300, Alexandria, VA 22314. (703) 739-9384. <http://www.migraines.org>.

Adrienne Wilmoth Lerner