Headache medications are drugs used to soothe discomfort that a patient may experience in the head. They may work by blocking pain, reducing inflammation or opening restricted blood vessels.  However, exactly how most of these medications exert their analgesic effects still remains unclear.

Headache medications may provide the following types of relief:

• Abortive therapy, where the medications provide symptomatic relief. Relieves common headache symptoms after they already have appeared. This may include pain that occurs in the head and other symptoms associated with certain types of headaches, such as nausea and vomiting that may occur with migraines. Examples of such drugs include triptans, aspirin, acetaminophen, ibuprofen and narcotic analgesics (opioids). Some are available over the counter, but others require a prescription.
  
  
• Preventive therapy. Used to treat migraines, tension headaches and cluster headaches that may occur frequently. These drugs are taken regularly in hopes of preventing headache symptoms before they appear if the headaches occur on a frequent and predictable schedule. Most of these medications require a prescription.

Many medications are used to treat headaches. Some of the most common are available over the counter (without a prescription). The drugs most often used to treat common headaches include:

• Aspirin. Another name for acetylsalicylic acid. Salicylate is a naturally occurring substance found in the bark of willow trees that was used for hundreds of years as a way to relieve pain. Aspirin was introduced to the U.S. market in 1899. It belongs to a class of medications known as nonsteroidal anti-inflammatory drugs (NSAIDs). This drug reduces the pain, inflammation, fever, redness, swelling and discomfort associated with medical disorders such as headaches, infections and arthritis. Aspirin also helps prevent blood from clotting, and has been shown to reduce the risk of heart attacks and certain forms of strokes.
  
  Scientists are unsure exactly how aspirin works, but it may act on the hypothalamus (part of the brain that regulates body temperature and other autonomic activities) and block the generation of pain impulses. It also reduces inflammation by inhibiting prostaglandin production, and this may also provide pain relief. Prostaglandins are hormone-like substances in the body that mediate a wide range of physiological functions.
  
  
• Acetaminophen. Medication used to relieve mild to moderate pain. It can also be used as a fever reducer, but it does not significantly reduce the stiffness, redness and inflammation associated with diseases such as arthritis. Acetaminophen first appeared as an over-the-counter drug in 1954. It belongs to the drug family called analgesics, and is often used as a painkiller by patients who cannot tolerate NSAIDs, such as aspirin or ibuprofen. Scientists are unsure exactly how acetaminophen works to relieve pain.
  
  
• Ibuprofen. An NSAID used to relieve many types of pain, including discomfort associated with headaches, muscle aches, arthritis, menstruation and many other conditions. It is usually taken in an over-the-counter formulation but is also available by prescription.

It is unknown exactly how ibuprofen works. However, it is believed that it works by inhibiting prostaglandin production.

Other drugs also may be taken to treat symptoms of specific types of headaches. For example, certain medications are known to be effective in treating symptoms related to migraines. These include:

• Triptans
• Dihydroergotamine mesylate
• Ergotamine tartrate and caffeine
• Isometheptene, dichloralphenazone and acetaminophen
• Butalbital compounds
• Metoclopramide

Finally, some classes of drugs used to treat other conditions are also known to be effective in preventing headaches before they start. These include:

• Anticonvulsants
  
• Antihistamines
  
• Blood pressure drugs (antihypertensives) including beta blockers and calcium channel blockers
  
• Corticosteroids
  
• Lithium (a preventive agent for cluster headaches)
  
• Tricyclic antidepressants

In some cases, certain headache medications (e.g., aspirin, acetaminophen) may be combined with caffeine or a sedative into a single drug for headache relief. Patients are advised to always follow their physician’s instructions regarding combining medications.

Though these medications often help relieve headache symptoms, they also can worsen symptoms if taken too frequently. The most effective method of treating headaches is to use these medications in conjunction with other preventive measures, such as eating a well-balanced diet, engaging in regular exercise, participating in relaxation therapy and making other health lifestyle changes.