psd-502 and Neuralgia

Topical capsaicin has been reported to be beneficial for the treatment of neurogenic pain. However, due to the burning pain associated with topical capsaicin, many patients discontinue treatment before therapeutic benefits are obtained. This study assessed the efficacy of EMLA (eutectic mixture of 2.5% prilocaine and 2.5% lidocaine) to block pain induced by the topical application of 1% capsaicin. Nine healthy subjects (five males and four females) participated in the study. High dose topical capsaicin (1%) was applied to a 2.5 x 2.5 cm region of both volar forearms for 6 h. One arm was pretreated (for 2 h) and cotreated with EMLA, and the other arm served as vehicle control. Average and peak pain ratings were recorded at 15-min intervals using a 0 (no pain) to 10 (worst possible pain) scale. Average and peak pain ratings were significantly lower at the EMLA site during the first 15-30 min of capsaicin treatment. However, for the remaining 5.5 h of capsaicin treatment, the pain ratings at the EMLA and vehicle sites were not significantly different. The 6 h treatment with high dose topical capsaicin (1%) produced significant desensitization to heat stimuli that was not affected by EMLA treatment. EMLA fails to produce a long lasting attenuation of the pain induced by topical application of 1% capsaicin. These results argue against the use of EMLA to block pain to topical capsaicin during the treatment of neurogenic pain.

Topics: Administration, Topical; Adult; Anesthetics, Local; Capsaicin; Drug Tolerance; Female; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Male; Middle Aged; Neuralgia; Pain Threshold; Prilocaine

The analgesic effects of single and repeated applications of a eutectic mixture of local anaesthetics (EMLA) cream on both spontaneous and evoked pains were evaluated in 11 patients with post-herpetic neuralgia (PHN). Detection thresholds, pain thresholds and the responses to suprathreshold mechanical and thermal stimuli were quantitatively determined at baseline, 30 min after the first application and after a series of daily applications over six consecutive days (duration of application: 5 h/day). In the acute situation, EMLA produced an overall anaesthetic effect without significantly reducing spontaneous ongoing pain and mechanical allodynia. Repeated applications significantly reduced paroxysmal pain and both the dynamic and static subtypes of mechanical hyperalgesia. The effects on spontaneous ongoing pain were more variable. They were inversely correlated to the magnitude of the thermal deficit at baseline, and were significant only in patients with dynamic mechano-allodynia. Pathophysiological implications of these results are discussed.

Topics: Aged; Aged, 80 and over; Anesthetics, Combined; Anesthetics, Local; Female; Herpesviridae Infections; Hot Temperature; Humans; Hyperalgesia; Lidocaine; Lidocaine, Prilocaine Drug Combination; Male; Middle Aged; Neuralgia; Pain; Pain Threshold; Prilocaine; Sensation

EMLA cream is an acronym for eutectic mixture of local anesthetics. It contains lidocaine and prilocaine creams. A eutectic preparation, applied topically, penetrates into the dermis after an application period of 1 to 2 hours. This case report describes the successful treatment with EMLA cream of post-herpetic neuralgia, which was resistant to other modes of therapy, and briefly discusses the pharmacology of EMLA cream.

Topics: Administration, Topical; Aged; Anesthetics, Local; Drug Combinations; Female; Herpesviridae Infections; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Methemoglobinemia; Neuralgia; Pain Measurement; Prilocaine

Topics: Aged; Dermatitis, Allergic Contact; Drug Combinations; Drug Hypersensitivity; Female; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Neuralgia; Ointments; Patch Tests; Prilocaine

Topics: Anesthetics, Local; Drug Combinations; Herpes Zoster; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Neuralgia; Prilocaine

The analgesic efficacy of 5% of EMLA cream (5 or 10 g) when applied for 24 h periods was evaluated in 5 female and 7 male patients (mean age 69 years, range 50-85 years) with refractory post-herpetic neuralgia (PHN). Mean visual analogue pain intensity scores for all patients were significantly improved 6 h after application (P less than 0.05). In a subgroup of patients with facial PHN receiving EMLA cream, 5 g (n = 4), there were significant improvements in pain intensity scores at 6 h (P less than 0.05). 8 h (P less than 0.01) and 10 h (P less than 0.01) after application. Plasma lignocaine and plasma prilocaine concentrations were well below potentially toxic levels in all patients after application.

Topics: Administration, Topical; Aged; Aged, 80 and over; Analgesics; Drug Combinations; Female; Herpes Zoster; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Male; Middle Aged; Neuralgia; Prilocaine