Guideline is: if using pain meds 3-5x/week and you have increase in frequency of headaches, it's good change from overuse. No test except to stop the uspect med and wait. Change in pattern confirms the problem
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Neurology. 2006 Jul 11;67(1):109-13.

Medication-overuse headache in patients with cluster headache.

Paemeleire K, Bahra A, Evers S, Matharu MS, Goadsby PJ.

Headache Group, Institute of Neurology, Queen Square, London, UK.

OBJECTIVE: Medication-overuse headache (MOH) in cluster headache (CH) patients is incompletely described, perhaps because of the relatively low prevalence of CH. METHODS: The authors describe a retrospective series of 17 patients (13 men, 4 women) with CH who developed MOH in association with overuse of a wide range of monotherapies or varying combinations of simple analgesics (n = 9), caffeine (n = 1), opioids (n = 10), ergotamine (n = 3), and triptans (n = 14). The series includes both episodic (n = 7) and chronic (n = 10) CH patients. RESULTS: A specific triptan-overuse headache diagnosis was made in 3 patients, an opioid-overuse headache diagnosis was made in 1 patient, and an ergotamine-overuse headache diagnosis was made in 1 patient. IN APPROXIMATELY HALF OF THE PATIENTS (N = 8), THE MOH PHENOTYPE WAS A BILATERAL, DULL, AND FEATURELESS DAILY HEADACHE. IN THE OTHER 9 PATIENTS, THE MOH WAS CHARACTERIZED BY AT LEAST ONE ASSOCIATED FEATURE, MOST COMMONLY NAUSEA (N = 6), EXACERBATION WITH HEAD MOVEMENT (N = 5), OR THROBBING CHARACTER OF THE PAIN (N = 5). The common denominator in 15 patients was a personal or family history, or both, of migraine. The 2 other patients gave a family history of unspecified headaches. Medication withdrawal was attempted and successful in 13 patients. CONCLUSIONS: Medication-overuse headache is a previously underrecognized and treatable problem associated with cluster headache (CH). CH patients should be carefully monitored, especially those with a personal or family history of migraine.

PMID: 16832088 [PubMed]
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Curr Pain Headache Rep. 2008 Apr;12(2):122-7.
Medication-overuse headache in patients with cluster headache.

Paemeleire K, Evers S, Goadsby PJ.

Headache Clinic, Department of Neurology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. koen.paemeleire@ugent.be

Cluster headache (CH) is associated with the most severe pain of the primary headache disorders. Barriers to optimal care include misdiagnosis, diagnostic delay, undertreatment, and mismanagement. Medication-overuse headache (MOH) may further complicate CH and may present as increased CH frequency or development of a background headache, which may be featureless or have some migrainous quality. A personal or familial history of migraine appears to be strongly associated with the development of MOH in CH, at least with the phenotype of background headache. Patients with CH, especially those with a personal and/or family history of migraine, must be carefully monitored for MOH, and medication withdrawal should be considered if a CH patient presents with features of MOH.

PMID: 18474192 [PubMed]