Systemic alpha-adrenergic blockade with phentolamine: a diagnostic test for sympathetically maintained pain.

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Raja SN, Treede RD, Davis KD, Campbell JN

Systemic alpha-adrenergic blockade with phentolamine: a diagnostic test for sympathetically maintained pain.

Anesthesiology. 1991 Apr;74(4):691-8. doi: 10.1097/00000542-199104000-00012.

PubMed ID

1848966 [ View in PubMed

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Abstract

The diagnosis of sympathetically maintained pain (SMP) is typically established by assessment of pain relief during local anesthetic blockade of the sympathetic ganglia that innervate the painful body part. To determine if systemic alpha-adrenergic blockade with phentolamine can be used to diagnose SMP, we compared the effects on pain of local anesthetic sympathetic ganglion blocks (LASB) and phentolamine blocks (PhB) in 20 patients with chronic pain and hyperalgesia that were suspected to be sympathetically maintained. The blocks were done in random order on separate days. Patients rated the intensity of ongoing and stimulus-evoked pain every 5 min before, during, and after the LASB and PhB. Patients and the investigator assessing pain levels were blinded to the time of intravenous administration of phentolamine (total dose 25-35 mg). The pain relief achieved by LASB and PhB correlated closely (r = 0.84), and there was no significant difference in the maximum pain relief achieved with the two blocks (t = 0.19, P greater than 0.8). Nine patients experienced a greater than 50% relief of pain and hyperalgesia from both LASB and PhB and were considered to have a clinically significant component of SMP. We conclude that alpha-adrenergic blockade with intravenous phentolamine is a sensitive alternative test to identify patients with SMP.

DrugBank Data that Cites this Article

Drugs

Phentolamine

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Phentolamine	Alpha-1 adrenergic receptors (Protein Group)	Protein group	Humans	Yes	Antagonist	Details
Phentolamine	Alpha-2 adrenergic receptors (Protein Group)	Protein group	Humans	Unknown	Antagonist	Details