Steven Bradshaw and colleagues explain the management of that all too common of problems--headaches

Headaches are a universal human experience that can be disabling.¹ Because they occur often, it is important to be familiar with the main types of headache and their management.

Primary and secondary headaches

Headaches are described as being either primary or secondary. Primary headaches include migraine, cluster, and tension-type headaches; they have no underlying causes that are readily identifiable. Clinical diagnoses, therefore, are based on features in the history, such as those defined by the International Headache Society (boxes 1 to 4).¹ Secondary headaches are related to specific conditions (box 5).

Migraine

Migraine is a common condition that causes considerable pain and disability. A few attacks per year is typical, and certain foods act as triggers--notably cheese and chocolate, which contain tyramine.² There are two types of attack: (a) migraine with aura--the throbbing headache is preceded by a prodromal stage where sensory disturbances are present--and (b) migraine without aura--the first symptom is the headache. Migraines last between 4 and 72 hours. Most patients have both types of attack. Treatment regimens, consisting of acute treatment and prophylactic treatment, do not differ significantly (box 6).

Treatment for acute attacks

Simple analgesics and anti-emetics

Over the counter drugs--such as aspirin and paracetamol, preferably in soluble form to increase absorption rate--are effective in most mild migraine attacks. Delayed gastric emptying, due to reduced peristalsis, often occurs in an attack: combination therapy with metoclopramide or domperidone promotes absorption of the drug--for example, Paramax contains 500 mg paracetamol and 5 g metoclopramide.³ When given intravenously, metoclopramide and the other dopamine receptor antagonists, chlorpromazine and prochlorperazine, are capable of stopping attacks, but their precise mechanism of action is unknown.⁴

Other anti-emetics, including the histamine antagonists cyclizine and buclizine, may be useful in treating the nausea associated with migraine.

Non-steroidal anti-inflammatory drugs (NSAIDs)

Naproxen, ibuprofen, flurbiprofen, diclofenac, and other non-steroidal anti-
inflammatory drugs (NSAIDs) are effective first line acute treatments. The NSAID tolfenamic acid (Clotam) is specifically licensed for the treatment of acute migraine attacks.³ Diclofenac may be given orally, intramuscularly, or as a suppository--
particularly useful for attacks where severe vomiting is a feature.

5-HT₁ agonists

5-HT₁ agonists are widely used in the treatment of migraine. They are thought to modulate central pain mechanisms by reducing levels of the transmitter substance calcitonin gene related peptide.⁵ The triptan class of drugs, of which sumatriptan (Imigran) was the first to be licensed, are 5-HT₁ agonists; they are possibly the most effective agents at relieving the symptoms of an acute migraine.

Sumatriptan can be used in the initial headache phase of the attack and is the preferred treatment for patients who do not respond to conventional analgesics; administration can be oral, via an intranasal spray, or by subcutaneous injection. The latter two methods avoid first pass metabolism: therapeutic blood levels are achieved quickly.

Rizatriptan (Maxalt) is newer and, when given orally, acts faster than sumatriptan.⁵ "Melt" wafers of rizatriptan are may be helpful in cases of nausea with migraine, as they can be taken without fluids, reducing the likelihood of vomiting. Side effects include chest pain and paraesthesia.

Triptans are contraindicated in patients with ischaemic heart disease and should not be given with ergotamine.² Other triptans have also become available, including almotriptan, naratriptan, and zolmitriptan.

Ergotamine

Although the mode of action is not fully understood, ergotamine is still used to manage acute attacks. It is a vasoconstriction causing * adrenoceptor agonist. It is also a high affinity agonist at 5-HT₁ receptors. Its therapeutic value is limited by its poor absorption and unpleasant side effects: abdominal pains, nausea and vomiting, and muscle cramps.

Because of its vasoactive properties, ergotamine is contraindicated in patients with peripheral vascular disease and Raynaud's phenomenon. Overdose of ergotamine can cause peripheral gangrene: its use is best avoided, except in severe and difficult to control cases. Its use by doctors is in rapid decline.

Prophylactic treatment

Prophylactic treatment aims to reduce the number of occurrences, the duration, and the severity of attacks: it should be considered if the patient has more than one attack per month. The need for treatment should be reviewed every six months.

The main classes of prophylactic agents used in migraine are ß blockers and pizotifen. Tricyclic antidepressants, such as amitriptyline, and certain anticonvulsants, particularly valproate and gabapentin (Neurontin), are also sometimes used, although this use is unlicensed.

The ß adrenoceptor antagonists propranolol, nadolol, metoprolol, and timolol are all effective for migraine prophylaxis. Propranolol is probably the most commonly used, and these drugs are well tolerated by most patients.

Other drugs have been used with variable success. The 5-HT₁ antagonist methysergide (Deseril) is specifically licensed for migraine prophylaxis. This drug works rapidly, but because of the risk of rare but dangerous adverse effects, including retroperitoneal, pleural, and cardiac fibrosis, it should only be used under hospital supervision.

Cyproheptadine (Periactin), an antihistamine with calcium channel blocking and serotonin antagonist properties, used to be popular for childhood migraine,⁶ but it has now largely been replaced by pizotifen. Most prophylactic drugs are mildly sedating and may cause weight gain. The calcium channel blockers verapamil and nifedipine are also occasionally used in migraine prophylaxis, and, although controversial, they are effective in some patients.

The successful management of migraine is not just about drugs. Conservative measures such as avoiding trigger factors and using relaxation techniques may also be useful.

Cluster headaches (migranous neuralgia)

This is an uncommon type of headache, of unknown cause, which is often misdiagnosed. Cluster headaches derive their name from their tendency to cluster over time. Each cluster lasts one to two months, with a painful headache once or twice a day, each lasting between 30 and 45 minutes. Patients typically experience one or two clusters per year.

The pain is usually located in the orbit and may be associated with local redness and swelling, nasal congestion, or crying. Effective treatment is rewarding for the patient and the doctor, though the mode of action of drugs is not clear.

Treatment of cluster headaches

Acute cluster headaches escalate to maximum pain within 15 minutes: drugs which act fast are needed. Inhaling 100% oxygen terminates 70% of attacks within 10 minutes and 90% within 15 minutes.⁷ Patients may keep a supply at home to treat their attacks. A 6 mg subcutaneous injection of sumatriptan, or intranasal administration, is equally effective. ²

Prophylaxis is required for chronic cluster headaches without remission and is generally effective. At the onset, a 7-10 day course of oral prednisolone (60-80 mg/day) often terminates the attack. A 2-4 mg dose of methysergide, three or four times daily, is an alternative. ⁴

Tension-type headaches

Tension-type headaches are the most common type of primary headache, and patients characteristically describe it as a tight band constantly pressing around the head without diurnal variation and with
few migraine-like features: it is very rarely associated with nausea, photophobia, or phonophobia.

The International Headache Society's criteria allow the presence of either photophobia or phonophobia. If both findings are present then a diagnosis of migraine should be considered.

Stress is a trigger for tension-type headaches.⁸ Food triggers occur in only 14% of patients with tension-type headaches: doctors should consider a diagnosis of migraine if a food trigger is thought to be present.⁴ The typical patient is a highly stressed person--for example, a student revising for finals or a workaholic business executive.

Treatment of tension-type headaches

Tension-type headaches respond to many of the prophylactic drugs used for migraine. For mild attacks, most patients successfully self medicate with over the counter remedies. For more frequent attacks, NSAIDs, triptan drugs, and careful use of muscle relaxants can be effective. Probably the best cure for tension-type headaches is to avoid stress and establish a regular sleep pattern.²

Conclusion

Successful treatment of primary headache depends on a specific diagnosis being made, good patient compliance, and an interested doctor. Current treatment strategies for headache include both conservative and medical therapies. Various drugs are used for both the treatment of acute attacks and for prophylaxis; the newer 5-HT₁ agonists have made a big impact on the lives of people who get headaches (box 6). There is certainly more to the treatment of primary headache than paracetamol.