Dihydroergotamine belongs to a family of medications called ergot alkaloids. It is used to help relieve the pain of migraine headaches. These medications work by constricting blood vessels in the head. This relieves the dilation (widening) of blood vessels, which is related to migraine headache pain.

Dihydroergotamine is most effective if used at the first sign of a migraine headache with or without aura (warning signs that occur prior to the onset of a migraine headache). It is not effective for other types of headache. Relief is often obtained within thirty minutes of using the medication. Extra medication may be given if some relief is not obtained after the initial dose. (See the following section for maximum doses.)

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

The recommended dose of dihydroergotamine is one spray in each nostril (total of 2 sprays) at the first sign or symptom of a migraine headache, or as early as possible after the onset of migraine headache pain. If the migraine has not improved sufficiently after about 15 minutes, one additional spray can be used in each nostril (total of 2 more sprays).

One bottle of dihydroergotamine nasal spray contains 4 sprays. No more than 4 sprays (2 in each nostril, i.e., one bottle) should be used for any migraine attack. No more than 8 sprays (2 bottles) should be used in any 24-hour period. No more then 24 sprays (6 bottles) should be used in any 7-day period.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor.

The spray should be used in the following manner (see package insert for illustrated details):

• Start to prepare the sprayer only when you have a migraine attack.
• Slowly lift and bend back the lip of the blue seal to show the rubber stopper. Try not to break the blue seal.
• Completely remove the seal and metal collar in one piece, if possible. If the two should break apart, carefully continue removing the metal collar. The collar has a sharp edge - handle it with care.
• Gently pull the rubber stopper out of the bottle. Be careful not to spill the contents.
• Gently remove the transparent plastic protective cover from the bottom of the sprayer. Insert the sprayer into the bottle and tighten firmly onto the bottle in a clockwise direction.
• Holding the bottle upright, gently remove the blue plastic protective cap from the top of the sprayer.
• Prior to use, the sprayer must be primed (pumped 4 times in the air).
• Hold your head straight.
• Insert the sprayer into one nostril and pump the sprayer once to release the medication. Repeat in the other nostril (a total of 2 sprays).
• Don't blow your nose.
• Wait about 15 minutes. If you have not already experienced sufficient relief, or to obtain optimal efficacy and long-lasting relief, repeat the spray once in each nostril. Discard the bottle and sprayer after use or within 8 hours of preparation.
• Lie down in a quiet, dark room for a while after you use this medication. This may help with your treatment.

Store the product at room temperature.

Each mL of clear, colourless to faintly yellow solution contains dihydroergotamine mesylate USP 4 mg. Nonmedicinal ingredients: caffeine, dextrose, and water.

Do not use dihydroergotamine if you:

• are allergic to any of the ingredients
• are pregnant
• are breast-feeding
• are taking any of the following medications
• protease inhibitors (e.g., ritonavir, nelfinavir, indinavir)
• macrolide antibiotics (e.g., erythromycin, clarithromycin, troleandomycin)
• antifungal agents (e.g., ketoconazole, itraconazole)
• have coronary artery disease
• have diseases of blood circulation
• have uncontrolled high blood pressure
• have severely impaired liver function
• have severely impaired kidney function

There may be other conditions where the doctor may not want you to use this medication. Be sure to tell all health care professionals involved in your care about all your medical conditions.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who uses this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people using this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Stop using the medication and seek immediate medical attention if any of the following occur:

• chest pain
• cough, fever, sneezing, or sore throat
• feeling of heaviness in chest
• irregular heartbeat
• itching of the skin
• numbness and tingling of face, fingers, or toes
• pain in arms, legs, or lower back
• pain in back, chest, or left arm
• pale bluish-coloured or cold hands or feet
• shortness of breath or troubled breathing
• weak or absent pulses in legs

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are using this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Dependence: If you take dihydroergotamine for extended periods of time you may become dependent upon it and require progressively increasing doses for relief of headaches or to prevent the increasing unpleasant effects which may follow withdrawal of the medication.

Drowsiness/reduced alertness: You should not undertake activities requiring mental alertness, such as operating equipment or driving a vehicle, until you determine your response and sensitivity to this medication.

Overdose: It is important to stay within the limits of the recommended dosage of this medication and avoid excessive or prolonged use. An overdose of ergotamine is dangerous, and may cause the following effects:

• cold and pale skin
• confusion
• depression
• diarrhea
• dizziness
• drowsiness
• headache
• itching
• muscle pain
• nausea
• pain like that of angina
• rapid and weak pulse
• rise and/or fall of blood pressure (usually in that order)
• slow or fast heart rate
• thirst
• tingling and numbness of the extremities
• unconsciousness
• vomiting

If an overdose is suspected, seek medical help immediately.

Pregnancy: Dihydroergotamine may cause harm when taken during pregnancy. If you become pregnant while using this medication, contact your doctor immediately.

Breast-feeding: Dihydroergotamine passes into breast milk and may cause symptoms of vomiting, diarrhea, weak pulse, and unstable blood pressure in nursing infants. If you are breast-feeding you should not take this medication.

Children: The safety and effectiveness of this medication for children less than 16 years of age have not been established. It is not recommended for use by children.

There may be an interaction between dihydroergotamine and any of the following:

• alpha-/beta-agonists (e.g., epinephrine, pseudoephedrine)
• amoxapine
• antifungal agents (e.g., ketoconazole, itraconazole)
• aprepitant
• beta-blockers (e.g., atenolol, metoprolol, propranolol, sotalol)
• bromocriptine
• cobicistat
• conivaptan
• diltiazem
• doxepin
• dronedarone
• grapefruit juice
• HIV protease inhibitors (e.g., ritonavir, nelfinavir, indinavir)
• letermovir
• linezolid
• lithium
• macrolide antibiotics (e.g., erythromycin, clarithromycin, troleandomycin)
• mifepristone
• mirtazapine
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
• narcotic pain relievers (e.g., fentanyl, meperidine, tramadol)
• nicotine
• nitroglycerin
• other ergot medications (e.g., methysergide, ergonovine, ergoloid mesylates)
• protein kinase inhibitors (e.g., crizotinib, imatinib, ribociclib)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, escitalopram, fluoxetine)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
• trazodone
• tricyclic antidepressants (e.g. amitriptyline, imipramine)
• "triptan" migraine medications (e.g., eletriptan, rizatriptan, sumatriptan)
• tryptophan
• verapamil
• vilazodone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.