I did some research and found the following on Midrin:
Generic ingredients: Isometheptene mucate, Dichloralphenazone, Acetaminophen
Why is this drug prescribed?
Midrin is prescribed for the treatment of tension headaches. It is also used to treat vascular headaches such as migraine.
Most important fact about this drug
Midrin can be used only after the headache starts. It does not prevent headaches.
How should you take this medication?
You should start taking Midrin at the first sign of a migraine attack.
Do not take more than the maximum dose of Midrin.
Take this medication exactly as prescribed by your doctor.
--If you miss a dose...
Take this medication only as needed.
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor immediately. Only your doctor can determine whether it is safe for you to continue taking Midrin.
Side effects may include:
Short periods of dizziness, skin rash
Why should this drug not be prescribed?
Unless directed to do so by your doctor, do not take Midrin if you have the eye condition called glaucoma or severe kidney disease, high blood pressure, a physical defect of the heart, or liver disease, or if you are currently taking antidepressant drugs known as MAO inhibitors, including Nardil and Parnate.
Special warnings about this medication
Take Midrin cautiously if you have high blood pressure or any abnormal condition of the blood vessels outside of the heart, or have recently had a cardiovascular attack such as a heart attack or stroke.
Possible food and drug interactions when taking this medication
Avoid alcoholic beverages.
If Midrin is taken with certain other drugs, the effects of either drug could be increased, decreased, or altered. It is especially important to check with your doctor before combining Midrin with the following:
Acetaminophen-containing pain relievers such as Tylenol
Antidepressants classified as MAO inhibitors, including Nardil and Parnate
Antihistamines such as Benadryl
Central nervous system depressants such as Halcion, Valium and Xanax
Special information if you are pregnant or breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding your baby, check with your doctor before taking Midrin.
Relief of Migraine Headache
The usual dosage is 2 capsules at once, followed by 1 capsule every hour until the headache is relieved; do not take more than 5 capsules within a 12-hour period.
Relief of Tension Headache
The usual dosage is 1 or 2 capsules every 4 hours up to a maximum of 8 capsules a day.
I have a problem with my blood and it generally starts my migraine headaches. I take a Beta Blocker, Nadolol, to reduce the effect on my migraines. It doesn't entirely prevent my migraines, but it does reduce their severity. I don't get as serious throbbing.
I found on another site how Midrin works:
ACTIONS: Isometheptene Mucate, a sympathomimetic amine, acts by constricting dilated cranial and cerebral arterioles, thus reducing the stimuli that lead to vascular headaches. Dichloraiphenazone, a mild sedative, reduces the patient's emotional reaction to the pain of both vascular and tension headaches. Acetaminophen raises the threshold to painful stimuli, thus exerting an analgesic effect against all types of headaches.
Other medications that work simarlarily are Triptans. They don't include Acetaminophen or sedatives like Midrin but do constrict dilated blood vessels.