Throwing a few recent articles at you:

Headache. 2009 Feb;49(2):286-91.
Intravenous lidocaine in the treatment of refractory headache: a retrospective case series.

Marmura M, Rosen N, Abbas M, Silberstein S.

Jefferson Headache Center-Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA.

BACKGROUND: New treatments are needed to treat chronic daily headache (CDH) and chronic cluster headache (CCH). New treatments are needed to treat this population and intravenous (IV) lidocaine is a novel treatment for CDH. OBJECTIVE: The aim of this study was to examine the use of IV lidocaine for refractory CDH patients in an inpatient setting. METHODS: This was an open-label, retrospective, uncontrolled study of IV lidocaine for 68 intractable headache patients in an inpatient setting. We reviewed the medical records of patients receiving IV lidocaine between February 6, 2003 and June 29, 2005. RESULTS: Pretreatment headache scores averaged 7.9 on an 11-point scale and posttreatment scores averaged 3.9 representing an average change of 4. Average length of treatment was 8.5 days. Lidocaine infusion was generally well tolerated with a low incidence of adverse events leading to discontinuation of treatment. CONCLUSIONS: This study suggests benefit of lidocaine treatment and the need for further prospective analyses. The mechanism of lidocaine in treating headache is unknown.

PMID: 19222600 [PubMed]
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Headache. 2007 Dec 7 [Epub ahead of print]
Clomiphene Citrate for Treatment Refractory Chronic Cluster Headache.

Rozen T.

Michigan Head Pain and Neurological Institute, Ann Arbor, MI, USA.

A treatment refractory chronic cluster headache patient is presented who became cluster-free on clomiphene citrate. The author has previously reported a SUNCT patient responding to clomiphene citrate. Hypothalamic hormonal modulation therapy with clomiphene citrate may become a new preventive choice for trigeminal autonomic cephalalgias. The possible mechanism of action of clomiphene citrate for cluster headache prevention will be discussed.

PMID: 18070056
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Headache. 2008 Feb;48(2):286-90. Epub 2007 Dec 7.
Clomiphene citrate for treatment refractory chronic cluster headache.

Rozen T.

Michigan Head Pain and Neurological Institute, Ann Arbor, MI 48104, USA.

A treatment refractory chronic cluster headache patient is presented who became cluster-free on clomiphene citrate. The author has previously reported a SUNCT patient responding to clomiphene citrate. Hypothalamic hormonal modulation therapy with clomiphene citrate may become a new preventive choice for trigeminal autonomic cephalalgias. The possible mechanism of action of clomiphene citrate for cluster headache prevention will be discussed.

Publication Types:
Review

PMID: 18070056 [PubMed]
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Eur J Neurol. 2007 Jun;14(6):694-6.

The use of gabapentin in chronic cluster headache patients refractory to first-line therapy.

Schuh-Hofer S, Israel H, Neeb L, Reuter U, Arnold G.

Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.sigrid.schuh-hofer@gmx.net

Chronic cluster headache (CCH) is a rare but challenging condition. About 20% of CCH patients get refractory to treatment. Gabapentin has recently been reported to be efficacious in the treatment of CCH. To test the potential of gabapentin as second-line drug, we prospectively studied the efficacy of gabapentin as add-on drug in eight patients suffering from CCH refractory to first-line treatment. Six of eight CCH patients responded to treatment. After the end of the study phase, the patients' clinical course was further followed up until January 2006. The longest period of being continuously pain-free under gabapentin treatment was 18 months. In some individuals, increasing doses were needed with time. We conclude that gabapentin may be offered as treatment trial in patients refractory to first-line treatment. However, patients may fail to respond to treatment and drug tolerance may occur with time.

PMID: 17539953 [PubMed
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Notice the line: this med stopped a small number of cycles totally....

Headache 2001 Sep;41(8):813-6 

Olanzapine as an Abortive Agent for Cluster Headache.

Rozen TD.

Department of Neurology, Jefferson Headache Center/Thomas Jefferson University Hospital, Philadelphia, Pa.

OBJECTIVE: To evaluate olanzapine as a cluster headache abortive agent in an open-label trial. BACKGROUND: Cluster headache is the most painful headache syndrome known. There are very few recognized abortive therapies for cluster headache and fewer for patients who have contraindications to vasoconstrictive drugs. METHODS: Olanzapine was given as an abortive agent to five patients with cluster headache in an open-label trial. THE INITIAL OLANZAPINE DOSE WAS 5 MG, AND THE DOSE WAS INCREASED TO 10 MG IF THERE WAS NO PAIN RELIEF. THE DOSAGE WAS DECREASED TO 2.5 MG IF THE 5-MG DOSE WAS EFFECTIVE BUT CAUSED ADVERSE EFFECTS. To be included in the study, each patient had to treat at least two attacks with either an effective dose or the highest tolerated dose. RESULTS: Five patients completed the investigation (four men, one woman; four with chronic cluster, one with episodic cluster). Olanzapine reduced cluster pain by at least 80% in four of five patients, and TWO PATIENTS BECAME HEADACHE-FREE AFTER TAKING THE DRUG. Olanzapine typically alleviated pain within 20 minutes after oral dosing and treatment response was consistent across multiple treated attacks. The only adverse event was sleepiness. CONCLUSIONS: Olanzapine appears to be a good abortive agent for cluster headache. IT ALLEVIATES PAIN QUICKLY AND HAS A CONSISTENT RESPONSE ACROSS MULTIPLE TREATED ATTACKS. IT APPEARS TO WORK IN BOTH EPISODIC AND CHRONIC CLUSTER HEADACHE.

PMID 11576207 PubMed

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Olanzapine has a brand name of "Zyprexa" and is a antipsychotic. Don't be put off by this primary usage. Several of the drugs used to treat CH are cross over applications, that is, drugs approved by the FDA for one purpose which are found to be effective with unrelated conditions--BJ.

Bob, once again, thank you for the valuable information.  I've not heard of lidocaine being used via IV.