Prevention of post-herpetic neuralgia: acyclovir and prednisolone versus epidural local anesthetic and methylprednisolone.

BACKGROUND: Treatment of herpes zoster (HZ) includes the use of acyclovir with or without steroids. An alternative therapy is the epidural administration of local anesthetics with or without steroids. This trial compared the efficacy of these two treatment regimens in the prevention of post-herpetic neuralgia (PHN). METHODS: Six hundred adults over 55 years of age with a rash of less than 7 days duration, and severe pain due to HZ, were enrolled and randomized to receive either intravenous acyclovir (10 mg/kg three times daily) for 9 days+prednisolone (60 mg per day with progressive reduction) for 21 days, or 6-12 ml bupivacaine (0.25%) every 6-8 or 12 h+methylprednisolone 40 mg every 3-4 days by epidural catheter during a period ranging from 7 to 21 days. Efficacy was evaluated at 1, 3, 6 and 12 months. PHN was assessed as pain and/or allodynia, and "abnormal sensations" (hypoesthesia, burning, itching, etc.). Statistical analysis was performed based on the intent-to-treat population. RESULTS: In the 485 patients who completed the study, the incidence of pain after 1 year was 22.2% (51 patients of 230) after acyclovir+steroids, and 1.6% (4 patients of 255) after epidural analgesia+steroids. The incidence of abnormal sensations was 12.2% (28 patients) after acyclovir+steroids, and 4.3% (11 patients) in group B. CONCLUSIONS: Epidural administration of local anesthetic and methylprednisolone is significantly more effective in preventing PHN at 12 months compared to intravenous acyclovir and prednisolone.

Topical axonal transport blocker vincristine prevents nerve injury-induced spinal neuron sensitization in rats.

The effect of vincristine (Vin, a fast axonal transport blocker) to prevent any alteration in the excitability of dorsal horn neurons, following peripheral nerve injury, was investigated on 31 rats: 20 with chronic constriction injury (CCI) of the sciatic nerve and 11 sham preparations. In 15 of the 20 CCI rats, a small piece of gelfoam soaked with Vin was applied to the sciatic nerve before ligation (Vin+); in the remaining 5 rats the nerve was ligated without Vin (Vin-). The 11 sham rats were 7 Vin+ and 4 Vin-. The dorsal horn neuronal activity was recorded after 2-3 postoperative (PO) weeks. In the CCI Vin- rats, the neurons showed increased spontaneous activity and hyperresponsiveness to noxious stimulus with prolonged afterdischarges, events considered to signal central neuron sensitization. In the CCI Vin+ rats, the neuronal spontaneous and stimulated activity values were significantly lower (p < 0.001) than in the CCI Vin- rats being comparable to normal values. In sham Vin+ and Vin- rats, the neuronal activities had normal values. Given the crucial role attributed to central neuron sensitization for the development of neuropathic pain, the possibility that vincristine, by blocking the axonal transport, exerts a preventive action on this syndrome is discussed.

[Postoperative intravenous analgesia]. / Analgesia postoperatoria endovenosa.

The authors report the results of two clinical studies on postoperative pain relief with PCA. In the first clinical study 44 patients, undergoing gynecologic surgery, were assigned at random to two groups. The first was treated by PCA (infusor Baxter) with morphine i.v. (basal bolus 0.05 mg/kg, loading doses 1 mg every 6-15'), the second with 10 mg morphine i.m. at the end of surgery and then on demand with a lock-out of 6h at least. In the 2nd clinical study, 40 elder patients submitted to orthopedic surgery, were assigned at random to two groups treated with PCA (morphine i.v., basal bolus 0.07 mg/kg, bolus PCA 0.007 mg/kg lock-out 15') and with continuous infusion (i.c.) (basal bolus 0.07 mg/kg, i.c. 0.02 mg/kg/h). Our data were analyzed with Student's "t" unpaired test and showed lower doses of the drug in the groups PCA (1st study PCA 25.98 mg/48h, i.m. 45.45 mg/48h, 2nd study PCA 0.155 mg/kg/12h, i.c. 0.311 mg/kg/12h) and lower rate of side effects in the same groups. Side effects were well controlled using symptomatic drugs. We proposed to our patients, at the end of observation, a questionnaire about general conditions, sleep, pain evaluation using a descriptive scale and retrospective evaluation. Patients and nurses agree PCA. Nursing staff expressed a positive opinion and patients said they benefitted from PCA. As reported, PCA appears from our results, valid and safe in postoperative pain relief.

Acute respiratory effects of sublingual buprenorphine: comparison with intramuscular morphine.

In this randomized, double-blind, placebo study, the respiratory effects of a single dose of sublingual buprenorphine (0.4 mg) were examined and compared with those induced by one dose of intramuscular morphine (10 mg) in a population of women, aged 25-65 years, admitted at the Hospital for Elective Surgery because of uterine fibromyomatosis. Some indices of control of breathing (P0.1, VT/TI, VE, VA, TI, TE, TI/TTot, RR), gas exchange parameters (D[A-a]O2, VD/VT, PAO2) and blood gases (PaO2, PaCO2) were measured in basal condition and at 30, 60, 90, 180 and 360 min after the administration of the drugs. No significant changes of the respiratory function were observed in patients who have received sublingual buprenorphine. In the morphine-group, however, mild PaO2 decrease and PaCO2 increase were found at 60 and 90 min (p less than 0.05), without any reduction of the respiratory drive activity, as shown by P0.1, VT/TI and VE. The significant FRC reduction, observed in the morphine-group (p less than 0.05), could have induced both TE shortening and RR increase with larger dead space ventilation and consequent fall of VA (p less than 0.05). These results suggest that the administration of one dose of sublingual buprenorphine (0.4 mg) does not cause any detrimental respiratory effect; on the other hand, an appreciable, although clinically trivial, worsening of the respiratory function results from intramuscular morphine (10 mg), in the absence of any obvious respiratory depression.

Buprenorphine vs. morphine via the epidural route: a controlled comparative clinical study of respiratory effects and analgesic activity.

Twelve patients with intense or very intense pain of the non-incident type, secondary to neoplasia, were divided at random into two groups and treated with an epidural dose of 3 mg of morphine in 10 ml of glucose solution (6 patients = group M) or with 0.3 mg of buprenorphine in the same vehicle (6 patients = group B). None of the patients had previously been treated with opioids by any route. After first determining basal values, the following assessments were carried out: (1) evaluation of the analgesic effect of the drugs with checks at 30 min and at 1, 2, 3, 4, 6 and 18 h after administration, using a visual analogue scale, a numerical rating scale and a simple descriptive scale; and (2) evaluation of effects on respiration by means of checks at 30 and 90 min and at 6 and 18 h, on control of breathing indices (P0.1; VE; VA; Ti/Ttot; VT/Ti; RR), gas exchange indices (delta(A-a)O2; VD/VT; pAO2; R) and blood gas and acid-base indices (paO2; paCO2; pH; HCO3-). The data obtained were analyzed statistically using analysis of variance and Student's t test. The study results showed very similar analgesic efficacy for both treatments at a single dosage level of morphine (3 mg) compared to buprenorphine (0.3 mg), which was approximately 3 times greater than an equivalent parenteral dose of morphine (10 mg). Analysis of the results revealed statistically, though not clinically, significant changes in respiratory function indices, only in the buprenorphine-treated group. The effects of buprenorphine on respiratory function, when administered epidurally at the above dosage, are less favourable than those of morphine in the early measurements, probably because of its greater systemic absorption; nevertheless, the risk of delayed respiratory depression appears to be less after buprenorphine than after morphine.

[Early diagnosis of pheochromocytoma in pregnancy]. / Diagnosi precoce di feocromocitoma in gravidanza.

The authors report a case of pheochromocytoma revealed by a de novo appeared hypertension in a young female patient at her 3rd trimester of pregnancy. An early diagnosis and an appropriate medical management allowed a successful maternal outcome. Since maternal and fetal prognosis of pheochromocytoma associated with pregnancy is strictly related to an antepartum diagnosis, the importance of suspecting pheochromocytoma as underlying cause of de novo appearing hypertension (or hypertension of unknown origin) during pregnancy is emphasized. Biochemical tests (plasma and/or urinary catecholamine or metabolite determination) are recommended as the most suitable approach to the screening of pheochromocytoma in pregnancy.