Cluster Headache Treatment & Management
Pharmacologic management of cluster headache (CH) may be classified into 2 general approaches as follows:
Abortive/symptomatic (eg, oxygen, triptans, ergot alkaloids, and anesthetics)
Preventive/prophylactic (eg, calcium channel blockers, mood stabilizers, and anticonvulsants)
Olanzapine  and kudzu  have also been used to treat CH, but their effectiveness has not been determined. Antihistamines, such as chlorpromazine, do not appear to be helpful in relieving CH symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be given for pain relief.
Various procedures may be performed on trigeminal nerve or autonomic pathways, including alcohol injections and section or avulsion of nerves for chronic refractory cases. Surgical treatment may be initiated if the patient has contraindications to medications or if medications are not effective; it is employed only in strictly unilateral cases. Radiofrequency (RF) thermocoagulation of the trigeminal ganglion has had promising results in some patients with intractable pain.
Treatment guidelines are available from the American College of Emergency Physicians, the National Headache Foundation, and Institute for Clinical Systems Improvement. [12, 13, 14] Neurologic consultation may be useful if the diagnosis is in doubt or for management of difficult cases.
Management of pregnant patients
CH is rare during pregnancy, but when it does occur, episodes tend to have the same character and severity as in nonpregnant patients.  Treatment options for pregnant women are poorly documented. The first line of treatment is pure oxygen via a nonrebreather mask (see image below). Triptans and ergot alkaloids should be avoided. The use of selected preventive medications, which are rated pregnancy category B, should be discussed thoroughly with the patient and her obstetrician. 
Non-rebreather oxygen mask with reservoir for the acute treatment of cluster headache. Courtesy of Wikipedia Commons.
Abortive agents are given to stop or reduce the severity of an acute CH attack, whereas prophylactic agents are used to reduce the frequency and intensity of individual headache exacerbations. In view of the fleeting, short-lived nature of the attacks, effective prophylaxis should be considered the cornerstone of management. The prophylactic regimen should start at the onset of a CH cycle and continue until the patient is headache-free for at least 2 weeks. The agent then may be tapered slowly to prevent recurrences.
Oxygen (8 L/min for 10 minutes or 100% by mask) may abort the headache if used early. [17, 18] The mechanism of action is unknown.
5-Hydroxytryptamine-1 (5-HT1 ) receptor agonists, such as triptans or ergot alkaloids with metoclopramide, are often the first line of treatment. Stimulation of 5-HT1 receptors produces a direct vasoconstrictive effect and may abort the attack.
The triptan that has received the most study in the setting of CH is sumatriptan. [13, 17, 18] Subcutaneous injections can be effective, in large part because of the rapidity of onset. Studies have indicated that intranasal administration is more effective than placebo but not as effective as injections; there is no evidence that oral administration is effective. A typical dose is 6 mg subcutaneously, which may be repeated in 24
hours. Nasal spray (20 mg) may also be used.
Other triptans that may be considered for abortive treatment of CH are zolmitriptan, naratriptan, rizatriptan, almotriptan, frovatriptan, and eletriptan. In addition, researchers have begun to explore the possibility of using triptans for prophylaxis of CH. 
Dihydroergotamine can be an effective abortive agent. It is commonly given intravenously (IV) or intramuscularly (IM) and may be self-administered; it can also be given intranasally (0.5 mg bilaterally).  Dihydroergotamine tends to cause less arterial vasoconstriction than ergotamine tartrate and is more effective when given early in a cluster attack.
Parenteral opiates may be used if relief is inadequate. The short-lived and unpredictable character of CH precludes effective use of oral narcotics or analgesics, though oral regimens may sometimes be helpful for residual soreness. Abuse potential does exist. Narcotics are not generally recommended for aborting CH.
Intranasal civamide and capsaicin have yielded good results in clinical trials. Application of capsaicin to the nasal mucosa led to a clinically significant decrease in the number and severity of cluster headaches; nasal burning was the most common adverse effect.
Intranasal administration of lidocaine drops (1 mL of a 10% solution placed on a swab in each nostril for 5 minutes) is possibly helpful; however, it requires a specific and, for many patients, difficult technique.
Calcium channel blockers may be the most effective agents for CH prophylaxis.  They can be combined with ergotamine or lithium. Of the calcium channel blockers, verapamil may be the most useful, though others, including nimodipine and diltiazem, have also been reported to be effective.
Lithium has been suggested as an option because of the cyclical nature of CH, which is similar to that of bipolar disorders. It effectively prevents CH (particularly in its more chronic forms)  and treats bipolar mood disorder, another cyclic illness. Responses vary (with chronic CH patients generally being more responsive), but lithium is still a recommended first-line agent for CH. There is a tendency for the effect to wane after dramatic relief is seen in the first week.
Methysergide, though no longer available in the United States, is very effective for episodic and chronic CH prophylaxis. It can often reduce pain frequency, particularly in younger patients with episodic CH. If it yields no improvement after 3 weeks, it is unlikely to be beneficial. It should not be given continuously for longer than 6 months; a drug-free interval of 3-4 weeks must follow each 6-month course.
A few relatively small controlled studies have found anticonvulsants (eg, topiramate and divalproex) to be effective in the prophylaxis of CH, though the mechanism of action remains unclear.
Corticosteroids are extremely effective in terminating a CH cycle and in preventing immediate headache recurrence. High-dose prednisone is prescribed for the first few days, followed by a gradual taper. Simultaneous use of standard prophylactic agents (eg, verapamil) is recommended. The mechanism of action in CH is still subject to speculation.
Tricyclic antidepressants are more helpful as prophylaxis of other headache syndromes. Beta blockers may worsen bradycardia occurring during the cluster attack.