There's a wide variety of medications used for Migraine, most of which are prescribed off-label. If cyproheptadine (Periactin) has been prescribed for you, or if you and your doctor have been considering it, here's some information that should be helpful.

Type of medication:

Cyproheptadine (Periactin) is an antihistamine that decreases the histamines in our bodies that creates sneezing, watery eyes and runny noses along with other allergy symptoms. It is also prescribed off-label as a Migraine and headache preventive.
 

Precautions:

• It is very important to talk with the doctor before giving cold and/or allergy medication to children.
• Using allergy and/or cold medications improperly could lead to death in very young children. It is not recommended to use this medication in children younger than four-years-old.
• If you are allergic to cyproheptadine do not use this medication.
• Do not use this medication if you have narrow-angle glaucoma or have a stomach ulcer or blockage.
• Do not use this medication if you have an enlarged prostate or urination problems.
• Do not use this medication if you are having an asthma attack or if you are elderly and/or have a debilitating disease.
• Taking cyproheptadine may reduce your reaction time and/or impair your thinking. Care needs to be taking when driving or operating machinery.
• Certain side effects may be increased if you drink alcohol and take cyproheptadine at the same time.
• If you have used MAO inhibitors such as Furoxone, Marplan, Nardil, Azilect, Eldepryl, Emsam, Zelapar or Parnate in the previous two weeks, do not use cyproheptadine. Doing so may create a dangerous medication interaction which could lead to potentially serious side effects. 

Pregnancy and Breastfeeding:

• FDA Pregnancy Category B. Animal studies have not been able to show any proof of fetal harm.   
• Although there is no proof that cyproheptadine passes through breast milk, the makers of this medication recommend that nursing mothers stop nursing, or stop taking the medication due to the potentially harmful effects in babies who nurse, taking into consideration the health of the mother.

Other medical conditions:

Be sure to let your doctor know of other medical problems you may have, including:

• asthma
• narrow-angle glaucoma
• heart disease
• high blood pressure
• an overactive thyroid
• a stomach ulcer or blockage
• urination issues or an enlarged prostate
• bladder neck blockage
• if you have a incapacitating disease or are elderly
• peptic ulcer disease
• problems with your  liver

Other medications:

Make sure your doctor knows about ALL the medications you take. The following medications are contraindicated (should not be taken with) when taking cyproheptadine;

• potassium chloride
• potassium citrate
• sodium phosphate/potassium phosphate
• urinary acidifiers

The following medications should be avoided when taking cyproheptadine;

• all Monoamine oxidase inhibitors or MAOI's
• potassium iodide
• pramlintide
• sodium oxybate

Medications that need to be monitored closely while taking cyproheptadine include;