In the U.S.—

In Canada—

• Vascular headache prophylactic

Methysergide (meth-i-SER-jide) belongs to the group of medicines known as ergot alkaloids. It is used to prevent migraine headaches and some kinds of throbbing headaches. It is not used to treat an attack once it has started. The exact way methysergide acts on the body is not known.

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For methysergide, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to methysergide or to other ergot medicines. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Methysergide is not recommended during pregnancy. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—This medicine passes into the breast milk and may cause unwanted effects such as vomiting, diarrhea, weak pulse, unstable blood pressure, and convulsions (seizures) in nursing babies.

Children—Methysergide can cause serious side effects in any patient. Therefore, it is especially important that you discuss with the child's doctor the good that this medicine may do as well as the risks of using it.

Older adults—Elderly people are especially sensitive to the effects of methysergide. This may increase the chance of side effects during treatment.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking methysergide, it is important that your health care professional know if you are using any other prescription or nonprescription (over-the-counter [OTC]) medicine, or if you smoke.

• Arthritis or
• Heart or blood vessel disease or
• Infection or
• Itching (severe) or
• Kidney disease or
• Liver disease or
• Lung disease—The chance of serious side effects may be increased

• High blood pressure or
• Stomach ulcer—Methysergide can make your condition worse

Take this medicine only as directed by your doctor. If the amount you are to take does not prevent your headaches from occurring as often as before, do not take more than your doctor ordered. Instead, check with your doctor. Taking too much of this medicine or taking it too frequently may cause serious effects such as nausea and vomiting; cold, painful hands or feet; or even gangrene.

If this medicine upsets your stomach, it may be taken with meals or milk. If stomach upset continues or is severe, check with your doctor.

Dosing—

The dose of methysergide will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of methysergide. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • For preventing migraine and other throbbing headaches:
    • Adults—2 milligrams (mg) (one tablet) two to four times a day.
    • Children—Use is not recommended.

Missed dose—

If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

If you have been taking this medicine regularly, do not stop taking it without first checking with your doctor. Your doctor may want you to reduce gradually the amount you are using before stopping completely. If you stop taking it suddenly, your headaches may return or worsen.

Your doctor will tell you how long you should take this medicine. Usually it is not taken for longer than 6 months at a time. If the doctor tells you to stop taking the medicine for a while, do not continue to take it. If your body does not get a rest from the medicine, it can have harmful effects.

This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Even if taken at bedtime, it may cause some people to feel drowsy or less alert on arising. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert .

If dizziness occurs, get up slowly after lying or sitting down. If the problem continues or gets worse, check with your doctor.

Since drinking alcoholic beverages may make headaches worse, it is best to avoid alcohol while you are suffering from them. If you have any questions about this, check with your doctor.

Since smoking may increase some of the harmful effects of this medicine, it is best to avoid smoking while you are using it. If you have any questions about this, check with your doctor.

This medicine may make you more sensitive to cold temperatures, especially if you have blood circulation problems. It tends to decrease blood circulation in the skin, fingers, and toes. Dress warmly during cold weather and be careful during prolonged exposure to cold, such as in winter sports. This is especially important for elderly people, who are more likely than younger adults to already have problems with their circulation.

Check with your doctor if a serious infection or illness of any kind occurs while you are taking methysergide, since an infection may make you more sensitive to the medicine's effects.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• Chest pain or tightness in chest;  convulsions (seizures);  difficult or painful urination;  dizziness (severe);  fever or chills ;  increase or decrease (large) in the amount of urine ;  leg cramps;  pain in arms, legs, groin, lower back, or side;  pale or cold hands or feet;  shortness of breath or difficult breathing ;  swelling of hands, ankles, feet, or lower legs  

Check with your doctor as soon as possible if the following side effects occur:

• More common
  • Abdominal or stomach pain;  itching;  numbness and tingling of fingers, toes, or face;  weakness in the legs 
  
  

• Less common or rare
  • Changes in vision;  clumsiness or unsteadiness ;  cough or hoarseness;  excitement or difficulty in thinking;  fast or slow heartbeat;  feeling of being outside the body;  hallucinations (seeing, hearing, or feeling things that are not there);  loss of appetite or weight loss;  mental depression;  nightmares;  raised red spots on skin;  redness or flushing of face;  skin rash;  unusual weight gain 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Diarrhea;  dizziness or lightheadedness, especially when you get up from a lying or sitting position;  drowsiness;  nausea or vomiting 
  
  

• Less common or rare
  • Constipation;  hair loss;  heartburn;  trouble in sleeping 
  
  

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this time check with your doctor if your headaches begin again or worsen.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.