Intravenous infusion of adenosine 5?-triphosphate alleviated a disabling postherpetic neuralgia

Abstract

the lateral site of the right leg as well as the dorsal and plantar sites of the right foot. The patient was initially treated at a dermatology clinic with oral valaciclovir (an antiviral agent) and diclofenac (an anti-inflammatory agent), and subsequently, with diclofenac alone for several weeks. Within a month of its onset, the pain in the leg and the dorsum of the foot subsided concomitantly with the skin rash healing. However, severe pain in the plantar site of the foot persisted.Three months after the initial onset, the patient presented at our pain clinic, in a wheelchair, because of intractable pain with severe tactile allodynia on the sole and on the heel of the right foot, which was so severe that it prevented her from walking normally. Resting spontaneous pain was moderate, being rated at 50 mm/ 100 mm on the visual analog scale (VAS). However, marked tactile allodynia was observed on the right heel, which was rated at 91/100 mm. Because of the severe touch-evoked allodynia, she could not stand on the right foot, nor could she wear a sock or shoe on the right foot. She could hardly walk, limping and relying mostly on the left foot, stepping on the right tiptoe, and she wore beach sandals. She was treated initially with oral amitriptyline and repeated (caudal) epidural blocks, which resulted in only a slight improvement in her pain status.Five months after the onset of pain, she was admitted to our hospital to study the mechanisms underlying her pain condition, and to seek potentially effective therapeutic measures. After obtaining institutional review board approval and written informed consent from the patient, we assessed various intravenous (IV) drugs for analgesic efficacy. Because the severe tactile allodynia was elicited most prominently when she was trying to walk, she was asked to rate her pain using VAS both at rest (for spontaneous pain) and when standing/stepping (for evoked tactile allodynia) before, during, and after administration of each test drug.

Analgesic effect of intravenous ATP on postherpetic neuralgia in comparison with responses to intravenous ketamine and lidocaine

“…Such slow onset-offset profiles of analgesic effects of intravenous infusion of ADO have been shown also in an animal nociceptive pain model [18]. These results may provide clinically important suggestions that a longerperiod infusion protocol (e.g., 2-3 h) [12], compared to a shorter-period infusion protocol (e.g., 1 h) [5][6][7][8][9], may provide better analgesia.…”

“…In our previous [12] and current reports, analgesic and antiallodynic effects of ATP seems to be slowly developing and long-lasting despite the extremely short plasma half-life of both ATP and ADO [10,15]. Such slow onset-offset profiles of analgesic effects of intravenous infusion of ADO have been shown also in an animal nociceptive pain model [18].…”

“…Compared to ketamine, ATP may be more feasible for clinical use because of its much less annoying side-effect profiles and its longer-lasting pain-relieving effects. Furthermore, pain relief lasting for months may occasionally be achieved with a single ATP infusion therapy [12], similarly to ADO or its analog [8,9,16,21]. ATP thus may deserve a trial in patients with devastating neuropathic pain refractory to other treatment modalities.…”

Clinical application of adenosine and ATP for pain control

“…When administered intravenously, however, ATP may act as adenosine at sites of action in both the peripheral and central nervous systems. Therefore, we have applied ATP to acute and chronic pain [7,8,21,66,67].…”

“…When administered intravenously, however, ATP inhibits pain behaviors in response to various noxious stimuli in animal acute nociceptive pain models [8,17]. Because ATP is rapidly broken down into adenosine in the bloodstream by ectonucleotidases, with its plasma halflife less than seconds [18,19], an intravenous dose of ATP may reach a site of action as adenosine and thus may exert antinociceptive rather than pronociceptive effects in both experimental and clinical pain conditions [7,8,20,21].…”