In order to examine whether repeated sciatic nerve blocks showed tachyphylaxis and continuity of sciatic nerve with spinal cord affected development of tachyphylaxis when assayed in vivo by duration of depression compound action potentials (CAP), rats were anesthetized with halothane, ventilated, monitored and supported with stable hemodynamics and temperature. Posterior tibial nerve distally and sciatic nerve in thigh were exposed, placed on bipolar silver electrodes for stimulation and recording respectively. Three sequential sciatic nerve blocks were performed between these electrodes using 0.15 ml of 3% chloroprocaine. Nine rats were chosen to observe the effects of repeated sciatic nerve blocks on CAP. In another 18 rats, a second investigator exposed the sciatic nerve near its origin at spinal cord and randomly performed nerve cut and sham (n=9), and closed the incision blinding the electrophysiologic investigator. The results showed that electrical stimulated tibial nerve induced sciatic nerve Aalpha/beta, Adelta, C fiber mediated CAP waves. CAP amplitudes were remained stable during whole experimental procedure. CAP amplitudes were decreased completely with 3% chloroprocaine blocked sciatic nerve and recovered fully. The duration of CAP depression were reduced with repeated blocks. There were no selective blocked effects on Aalpha/beta, Adelta, C fiber mediated CAP. With sciatic nerve cut proximally, there was no statistical significant tachyphylaxis with 3% chloroprocaine repeated blocked sciatic nerve, and the duration of first and third blocked Adelta fiber mediated CAP was 108+/-20 and 92+/-14 min respectively (P>0.05). In normal rats the duration of first and third blocked Adelta fiber mediated CAP was 110+/-20 and 75+/-16 min respectively (P<0.05). It was suggested that tachyphylaxis to local anesthetics can occur in rats repeated blocked sciatic nerve when assayed in vivo by duration of depression CAP. The continuity of sciatic nerve with spinal cord is one of the important factors affecting the development of tachyphylaxis.
Anesthetics, Local/*administration & dosage ; Nerve Block ; Procaine/administration & dosage ; Procaine/analogs & derivatives ; Sciatic Nerve ; *Tachyphylaxis/physiology

OBJECTIVETo compare lidocaine tincture and microemulsion for their transdermal permeation.

METHODSThe experimental model for percutaneous administration of lidocaine preparations in vitro was prepared using modified Franz diffusion cell.

RESULTSThe accumulated infiltration amount of lidocaine microemulsion in unit area was higher than that in its cream or tincture preparations.

CONCLUSIONThe transdermal permeation of lidocaine microemulsion in vitro can be more efficient than that of the tincture preparation, and the permeation is linearly dependent on the dose administered within a certain range.

Administration, Cutaneous ; Anesthetics, Local ; administration & dosage ; Drug Compounding ; Drug Delivery Systems ; Emulsions ; administration & dosage ; Lidocaine ; administration & dosage ; Skin Absorption

AIMTo examine the quantitative relationship between solution specific conductivity and the permeability of tetracaine HCl, and to investigate the effect of receptor solution specific conductivity on the iontophoretic transport.

METHODSAn in vitro study was carried out to determine the iontophoretic permeability of tetracaine hydrochloride through rat skin. Iontophoretic flux of tetracaine hydrochloride through excised rat skin was determined using Valia-Chien two-chamber diffusion cells with a constant d.c. current and Ag/AgCl electrodes. The specific conductivities of donor and receptor solution were also measured.

RESULTSIontophoretic flux of tetracaine hydrochloride increased with a decrease of anion (chloride ion) concentration in receptor. And the iontophoretic permeability (ER, ER is the enhancement ratio, and ER = iontophoretic flux/passive flux) for tetracaine hydrochloride was directly related to the conductivity of receptor solution when other conditions were held constant. Linear regressions confirmed that ER was related to inverse of overall specific conductivity of donor and receptor solution [1/(ks.d + ks.r), ks.d and ks.r are the specific conductivity of donor and receptor solution].

CONCLUSIONThe results suggest that specific conductivity of receptor solution may be a important factor for the iontophoretic permeability of a solute.

Administration, Cutaneous ; Anesthetics, Local ; administration & dosage ; pharmacokinetics ; Animals ; Iontophoresis ; Male ; Rats ; Rats, Sprague-Dawley ; Skin Absorption ; Tetracaine ; administration & dosage ; pharmacokinetics

In order to examine whether repeated sciatic nerve blocks showed tachyphylaxis and continuity of sciatic nerve with spinal cord affected development of tachyphylaxis when assayed in vivo by duration of depression compound action potentials (CAP), rats were anesthetized with halothane, ventilated, monitored and supported with stable hemodynamics and temperature. Posterior tibial nerve distally and sciatic nerve in thigh were exposed, placed on bipolar silver electrodes for stimulation and recording respectively. Three sequential sciatic nerve blocks were performed between these electrodes using 0.15 ml of 3% chloroprocaine. Nine rats were chosen to observe the effects of repeated sciatic nerve blocks on CAP. In another 18 rats, a second investigator exposed the sciatic nerve near its origin at spinal cord and randomly performed nerve cut and sham (n=9), and closed the incision blinding the electrophysiologic investigator. The results showed that electrical stimulated tibial nerve induced sciatic nerve Aalpha/beta, Adelta, C fiber mediated CAP waves. CAP amplitudes were remained stable during whole experimental procedure. CAP amplitudes were decreased completely with 3% chloroprocaine blocked sciatic nerve and recovered fully. The duration of CAP depression were reduced with repeated blocks. There were no selective blocked effects on Aalpha/beta, Adelta, C fiber mediated CAP. With sciatic nerve cut proximally, there was no statistical significant tachyphylaxis with 3% chloroprocaine repeated blocked sciatic nerve, and the duration of first and third blocked Adelta fiber mediated CAP was 108+/-20 and 92+/-14 min respectively (P>0.05). In normal rats the duration of first and third blocked Adelta fiber mediated CAP was 110+/-20 and 75+/-16 min respectively (P<0.05). It was suggested that tachyphylaxis to local anesthetics can occur in rats repeated blocked sciatic nerve when assayed in vivo by duration of depression CAP. The continuity of sciatic nerve with spinal cord is one of the important factors affecting the development of tachyphylaxis.
Anesthetics, Local ; administration & dosage ; Animals ; Nerve Block ; Procaine ; administration & dosage ; analogs & derivatives ; Rats ; Sciatic Nerve ; Tachyphylaxis ; physiology

ObjectiveTo evaluate the analgesic effect of intrarectal local anesthesia (IRLA) versus that of periprostatic nerve block anesthesia (PPNB) in initial transrectal ultrasound-guided prostate biopsy (TRUS-PB) for patients with different prostate volumes (PV).

METHODSA total of 253 patients undergoing initial TRUS-PB in our hospital from January 2014 to November 2017 were divided into three PV groups (<50 ml, 50－100 ml, and >100 ml), each again randomized into three subgroups (control, IRLA, and PPNB) with the random number table method. The pain during the procedure was assessed based on the Visual Analogue Scale (VAS) scores and the blind method was used by the biopsy operator, VAS valuator and data analyst.

RESULTSAmong the patients with PV <50 ml, the VAS scores in the blank control, IRLA, and PPNB subgroups were 4.39±0.87, 3.51±0.84 and 3.43±1.07, respectively, remarkably higher in the control than in the IRLA and PPNB groups (P<0.05), but with no statistically significant differences between the latter two (P>0.05). Among those with PV of 50－100 ml, the VAS scores in the three subgroups were 4.50±1.05, 4.38±1.13 and 3.38±1.44, respectively, markedly higher in the control and IRLA than in the PPNB group (P<0.05), but with no statistically significant differences between the former two groups (P>0.05). Among those with PV >100 ml, the VAS scores in the three subgroups were 5.19±1.05, 5.00±1.25 and 4.19±0.91, respectively, remarkably higher in the former two groups than in the latter (P<0.05), but with no statistically significant differences between the former two groups (P>0.05).

CONCLUSIONSEither IRLA or PPNB can be recommended for initial TRUS-PB in patients with PV <50 ml, PPNB for those with PV of 50－100 ml, and PPNB with other painkillers for those with PV >100 ml.

Administration, Rectal ; Aged ; Anesthesia, Local ; methods ; Anesthetics, Local ; administration & dosage ; Biopsy ; Humans ; Male ; Nerve Block ; methods ; Pain Measurement ; Pain, Procedural ; etiology ; prevention & control ; Prospective Studies ; Prostate ; pathology

AIMTo study the effect of lidocaine-dodecanol binary eutectic system on the transdermal permeation of lidocaine.

METHODSBinary eutectic mixture of different proportions of lidocaine and dodecanol were prepared and the patch containing the binary eutectic mixture was developed. The solubilities of pure lidocaine and lidocaine from the binary eutectic system were determined in pH 7.9 phosphate buffer. The transdermal flux of lidocaine from the patches containing the binary eutectic system and pure lidocaine were measured using Franz-type single diffusion cell.

RESULTSThe melting point of the lidocaine-dodecanol binary eutectic system was markedly lower than that of pure lidocaine. The steady state transdermal flux of lidocaine from the patch of the binary eutectic system was six times as much as that of pure lidocaine patch.

CONCLUSIONThe lidocaine-dodecanol binary eutectic system could produce high thermodynamic activity of the drug and the high driving force for transdermal permeation of lidocaine.

Administration, Cutaneous ; Anesthetics, Local ; administration & dosage ; pharmacokinetics ; Animals ; Dodecanol ; administration & dosage ; chemistry ; Drug Combinations ; Drug Stability ; Guinea Pigs ; Lidocaine ; administration & dosage ; pharmacokinetics ; Skin Absorption ; Solubility

This study describes the successful use of modified dorsolumbar epidural anesthesia with a fixed volume of anesthetic in a bovine referral center. Among the 130 Holstein cattle scheduled for flank surgery, 90 cattle received a mixed anesthetic consisting of 1 ml of xylazine hydrochloride and 3 ml of lidocaine hydrochloride by modified dorsolumbar epidural anesthesia. Eighteen cattle with dehydration and/or lameness received a mixed anesthetic containing 0.5 ml of xylazine and 3 ml of lidocaine. Infiltration anesthesia was performed in 22 cattle whose epidural space could not be reached in order to perform the flank surgery. The surgeries began about 12 min after the administration of the anesthetic and lasted for about 36 min. The modified method using a fixed volume of anesthetic was successfully introduced and effectively used in a bovine referral center. This modified method will allow veterinarians to save time and effort, thus lowering the cost of each surgery.
Anesthesia, Epidural/methods/*veterinary ; Anesthetics, Local/*administration & dosage ; Animals ; Cattle/*surgery ; Epidural Space ; Female ; Lidocaine/*administration & dosage ; Lumbar Vertebrae ; Xylazine/*administration & dosage

OBJECTIVETo prepare lidocaine nanoemulsion and investigate its transdermal delivery ability in vitro.

METHODSThe optimal Km (surfactant/cosurfactant) value and the component proportion were determined by pseudoternary phase diagrams combined with Origin software analysis. The diameter and distribution range were detected by Zeta particle size analysis instrument, and the morphology of the nanoemulsion was observed by electron microscope. The permeation flux of lidocaine was determined in vitro using the modified Franz diffusion cell combined with HPLC, and the cumulative transdermal absorption amount and the apparent skin transdermal velocity were compared among nanoemulsion, gel and tincture containing 5% lidocaine. The permeation mode of lidocaine nanoemulsion was analyzed.

RESULTSThe average drop size of lidocaine nanoemulsion was 29.8-/+14.4 nm, and 98% of the drop sizes ranged from 15.1 to 45.5 nm and 2% from 77.9 to 261.3 nm. The nanoemulsion drop showed a spherical morphology in a polydisperse system. The Kp value of the nanoemulsion (3.07-/+0.74 cm/h) was significantly higher than that of gel (1.27-/+0.35 cm/h) and tincture (0.97-/+0.18 cm/h), and the permeation rate of the nanoemulsion was 69.82-/+7.48 microg x cm(-2) x h(-1), which fitted the the Zero-order release dynamic procedure.

CONCLUSIONSThe component proportion of lidocaine nanoemulsion can be conveniently obtained through pseudoternary phase diagrams and Origin software analysis, and the drop size, distribution, morphology and system type can be determined by Malvern Zetasizer combined with electron microscopy. The results also indicate that the nanoemulsion system with high permeation rate may provide a new promising means for local anesthesia.

Administration, Cutaneous ; Anesthetics, Local ; administration & dosage ; metabolism ; Animals ; Emulsions ; Lidocaine ; administration & dosage ; metabolism ; Male ; Nanoparticles ; Particle Size ; Permeability ; Rats ; Rats, Wistar ; Skin Absorption ; drug effects

OBJECTIVETo determine the efficacy of 2% mepivacaine in conservative dentistry.

METHODSThe patients who needed cavity preparation or access to pulp chamber received local infiltration with 2% mepivacaine. Anesthesia time, anesthetic efficacy and cardiovascular system influences were assessed. 3% lidocaine with epinephrine served as control.

RESULTSIn experiment group, the anesthesia effects were quicker and anesthesia duration was longer than that in control group. Doctors highly appreciated the anesthetic efficacy. Two groups did not show any evident change in blood pressure and heart rate.

CONCLUSION2% mepivacaine is a safe and efficacious local anesthetic drug in conservative dentistry.

Adolescent ; Adult ; Anesthesia, Dental ; Anesthetics, Local ; Dental Pulp ; drug effects ; Female ; Humans ; Male ; Mepivacaine ; administration & dosage ; Middle Aged

AIMTo report a series of varicocelectomy performed under pure local anesthesia.

METHODSFrom July 1988 to June 2003, a total of 575 patients, aged between 15 and 73 years, underwent high ligation of the internal spermatic vein for treatment of a varicocele testis under a regional block in which a precise injection of 0.8 % lidocaine solution was delivered to involved tissues after exact anatomical references were made. A 100-mm visual analog scale (VAS) was used to assess whether the pain level was acceptable.

RESULTSThe surgeries were bilateral in 52 cases, and unilateral in 523 cases. All were successfully performed on an outpatient basis except in the case of two patients, who were hospitalized because their surgeries required general anesthesia. Overall, 98.6 % (567/575) of men could go back to work by the end of the first post-operative week and only 8 (1.4 %) men reported feeling physical discomfort on the eighth day. The VAS scores varied from 11 mm to 41 mm with an average of (18.5+/-11.3) mm that was regarded as tolerable.

CONCLUSIONThis study has shown varicocelectomy under local anesthesia to be possible, simple, effective, reliable and reproducible, and a safe method with minimal complications. It offers the advantages of more privacy, lower morbidity, with no notable adverse effects resulting from anesthesia, and a more rapid return to regular physical activity with minor complications.

Acetaminophen ; administration & dosage ; Adolescent ; Adult ; Aged ; Analgesics, Non-Narcotic ; administration & dosage ; Anesthesia, Local ; Anesthetics, Local ; administration & dosage ; Follow-Up Studies ; Humans ; Lidocaine ; administration & dosage ; Male ; Middle Aged ; Outpatients ; Pain, Postoperative ; drug therapy ; Postoperative Complications ; Varicocele ; surgery ; Vascular Surgical Procedures ; methods