Tachyphylaxis in local anesthetics

A successful peripheral nerve block not only involves a proper technique, but also a thorough knowledge and understanding of the physiology of nerve conduction and pharmacology of local anesthetics (LAs). This article focuses on what happens after the block. Pharmacodynamics of LAs, underlying mechanisms of clinically observable phenomena such as differential blockade, tachyphylaxis, C fiber resistance, tonic and phasic blockade and effect of volume and concentration of LAs. Judicious use of additives along with LAs in peripheral nerve blocks can prolong analgesia...

STUDY OBJECTIVE: To describe the use and adverse effects of chloroprocaine for epidural analgesia in young infants for infusion durations greater than 3.5 hours. DESIGN: A retrospective cohort review of the electronic medical record over a 14-month period. SETTING: The level IV neonatal intensive care unit of a 414-bed free-standing children's hospital. PATIENTS: Eighteen infants (mean age, 1.7 ± 1.8 months [0.03-6...

The intrathecal infusion of drugs to provide analgesia for terminally ill children with refractory pain is a rarely utilized but very effective technique. A number of pharmacological agents, most commonly opioids and local anesthetics, have been administered intrathecally for this purpose. However, tachyphylaxis and neuraxial opioid-related side effects can limit their utility. The alpha-2 agonist clonidine is commonly used to augment local anesthetic techniques for postsurgical pain in children and for the management of refractory cancer pain in adults, but there is only a single report of the use of clonidine intrathecally in a terminally ill child...

A profound tachyphylaxis of the acute nocifensive flinching (pain) response to subcutaneous injection of endothelin-1 (ET-1) into the hind paw footpad is shown by the reduced response to a second injection. Flinching from the second injection was 20% +/- 5%, 57% +/- 18%, 79% +/- 35%, and 100% +/- 17% of that from the first injection (both 200 micromol/L, 2 nmol) at respective intervals of 24, 30, 48, and 72 h. Inhibition of afferent impulses by local anesthesia of the sciatic nerve, reducing initial flinching to 6%-13% of control, did not affect the tachyphylaxis for the second injection at 24 h...

BACKGROUND: Severe pain in the head and neck is associated with a lowered quality of life and conventional pain therapy often does not provide adequate relief. The aims of this study were to investigate the efficacy, pain relief, benefits and adverse effects of intracisternal or high cervical (IHC) administration of bupivacaine in patients with severe pain in the head, neck and face regions. METHODS: Between 1990 and 2005, 40 patients (age 27-84 years) were treated with continuous IHC infusions of bupivacaine for various non-cancer (n=15) or cancer-related (n=25) refractory pain conditions (duration 1 month-18 years) in the head, neck, mouth and shoulder regions...

The present study was undertaken to investigate the effects of intravenous (i.v.) administration of rat hemopressin (rHP), 30-1000 microg/kg, on systemic arterial pressure (SAP), cardiac output (CO) and systemic vascular resistance (SVR) in the anesthetized rat. Bolus i.v. injections of rHP produced mild decreases in SAP that were dose-dependent. Since CO was not altered, the decreases in SAP reflect reductions in SVR. The systemic vasodilator response to rHP was not subject to tachyphylaxis. The systemic vasodilator response to rHP was abolished by L-nitro-arginine methylester (L-NAME) but was not altered by meclofenamate...

PURPOSE: To report the anesthetic management of labour pain and Cesarean section in a patient with urticaria pigmentosa at risk for systemic mastocytosis. CLINICAL: A 37-yr-old patient with a history of urticaria pigmentosa and an allergic reaction to a local anesthetic agent was seen in consultation at 36 weeks gestation. She previously tested negative for an allergy test to lidocaine. Recommendations to avoid systemic mastocytosis included: avoidance of histamine-releasing drugs, using lidocaine for labour epidural, and regional anesthesia in case of a Cesarean section...

BACKGROUND: Epidural administration of local anesthetics may lead to effective pain relief. However, tachyphylaxis or other problems following prolonged epidural anesthesia may develop and in many cases difficulties exist in the maintenance of the similar degree of sensory blockade. The present study was therefore performed to investigate the analgesic effect of continuous postoperative epidural infusion of ropivacaine with fentanyl in comparison with that of bupivacaine or ropivacaine alone...

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...

This report describes a pregnant woman with common bile duct stones whose colic was successfully treated by prolonged continuous epidural infusion of ropivacaine. A 32-year-old woman in the 26th week pregnancy complained of severe abdominal pain due to common bile duct stones. We adopted ropivacaine for infusion into the epidural space using patient controlled analgesia system considering fetoplacental circulation. We administered the solution successfully for 3 weeks, but we observed that the effectiveness of ropivacaine became reduced...

Switching from bupivacaine to lidocaine may improve intrathecal morphine analgesia in advanced cancer patients, possibly because of different spinal mechanisms limiting the hyperalgesic processes.

Substance abuse with cocaine is associated with multiple cardiovascular conditions, including myocardial infarction, dissection, left ventricular hypertrophy, arrhythmias, sudden death, and cardiomyopathy. Cocaine has effects to potentiate the physiologic actions of catecholamines and has direct effects on voltage-dependent sodium ion channels related to local anesthetic properties. The effects of cocaine can be augmented with concomitant alcohol consumption. Acute myocardial ischemia caused by cocaine may be related to in situ thromboisis and/or coronary vasospasm...

BACKGROUND: Tachyphylaxis to sciatic nerve blockade in rats correlates with hyperalgesia. Spinal inhibition of nitric oxide synthase with N(G)nitro-L-arginine methyl ester (L-NAME) has been shown to prevent hyperalgesia. Given systemically, L-NAME also prevents tachyphylaxis. The action of L-NAME in preventing tachyphylaxis therefore may be mediated at spinal sites. We compared systemic versus intrathecal potency of L-NAME in modulating tachyphylaxis to sciatic nerve block. METHODS: Rats were prepared with intrathecal catheters...

UNLABELLED: We conducted this retrospective study to document the efficacy and safety, and demonstrate the spectrum of indications for subcutaneously tunneled epidural catheters in the management of prolonged pain in pediatric patients. The charts of 25 patients with prolonged pain that was unresponsive to conventional opioid therapy (10: end stage malignancy, 8: extensive abdominal surgery, 7: trauma, etc.) and who received thoracic, lumbar, or caudal tunneled epidural catheters between 1995 and 1999 were reviewed for efficacy and catheter-related complications (infection or bleeding at the insertion site, toxicity related to local anesthetics, tachyphylaxis and respiratory depression)...

First, the fundamentals of impulse transmission and pain perception are revised. The role of the primary afferent nociceptors is explained. Dental pain is described as a form of acute pain and the mechanism of nociception is fundamental. Peripheral and central sensitization can evolve. The second part covers the pharmacological aspects. Local anesthetics reduce impulse transmission by interfering with the mechanism of normal depolarisation. Binding to specific receptors located at the nerve membrane, more specifically on the sodium channel, results in decreased or eliminated permeability to sodium ions and leads to interruption of nerve conduction...

The activity on intraocular pressure (IOP) of SR121463, a selective non-peptide arginin-vasopressin (AVP) V2 receptor antagonist, was investigated in a rabbit model of ocular hypertension. We first demonstrated that, in vitro, SR121463 displayed high competitive affinity for rabbit vasopressin V2 receptors (Ki = 2.1 +/- 1.2 nM). In vivo, SR121463 was instilled once (at concentrations ranging from 0.1 to 3%), or for 10 days (20 instillations) at 1% concentration, in the eye of ocular hypertensive rabbits (intraocular injection of 0...

Tachyphylaxis to local anesthetics is defined as a decrease in duration, segmental spread or intensity of a regional block despite repeated constant dosages. However, there is disagreement about the incidence of tachyphylaxis. In contrast to tachyphylaxis, pseudotachyphylaxis denotes time dependent variations in pain or circadian changes in the duration of local anesthetic action. Tachyphylaxis appears neither to be linked to structural or pharmacological properties of the local anesthetics nor to the technique or mode of their administration...

Procaine, a classical local anesthetic, produces, at low concentration (2-200 microM), excitation in a distinct population of small sensory neurons isolated from newborn rats (2D) and cultured for 1-5 days. The excitation or inward current (>50 pA) induced by procaine was observed in 59 out of 78 neurons. Nearly all these procaine-sensitive neurons (56 of 59) were also sensitive to capsaicin while 8 procaine-insensitive neurons responded to capsaicin (1 microM). In procaine-sensitive neurons tested for responsiveness to noxious heat, a 10 s temperature ramp from 24 to 48 degrees C induced an inward current of 413 +/- 47 pA (SEM, n = 27) and this current was enhanced, in the presence of procaine, about 3-fold (2...

In a randomised double-blind study, 45 patients, scheduled for major orthopaedic surgery under continuous spinal anaesthesia, received for relief of postoperative pain patient-controlled analgesia with either sufentanil 2 micrograms.ml-1, bupivacaine 0.0625% or a mixture of both by the intrathecal route. The mean (SD) consumption of sufentanil and bupivacaine during the first 12 h was 65.5 (27.1) micrograms and 18.2 (4.8) mg, respectively. Combining bupivacaine and sufentanil reduced the consumption of both to approximately 40% as compared to the administration of each component separately...

Bradykinin has been strongly implicated as a mediator of cardiac nociception. During coronary artery occlusion, the content of bradykinin in coronary sinus blood increases. In non-cardiac tissues nociception to bradykinin exhibits tachyphylaxis, however, this phenomenon has not been rigorously studied in the heart. This raises the question that repeated coronary occlusions may also result in tachyphylaxis, thereby reducing cardiac sensation on subsequent ischemic stimulation. We therefore examined the hypothesis that repetitive episodes of myocardial ischemia and of epicardial application of bradykinin demonstrate tachyphylaxis...