PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ANESTHETICS, LOCAL”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Progress in the development of ultra-long-acting local anesthetics.

BACKGROUND AND OBJECTIVES: Local anesthetic agents with a duration of action longer than the currently available local anesthetics could have widespread clinical application for the treatment of both chronic and acute pain. Over the last several decades, several different approaches have been used in the development of ultra-long-acting agents. There are currently promising preparations in development which may prove clinically useful in the near future. METHODS: A Medline search was conducted for relevant articles published in peer-reviewed journals between 1971 and 1996. Investigations related to prolongation of the effect of local anesthetics either by alterations in the local anesthetic molecule, use of new or novel agents, or use of new delivery systems were reviewed. In addition, bibliographies of relevant articles were searched to capture any articles that were missed by the Medline search. RESULTS: Over the last several decades, numerous attempts have been made to prolong the duration of action of local anesthetics. Initially, research focused on alterations in the local anesthetic molecule or the identification of new agents with local anesthetic action. Recently, the focus of much of the work has shifted to new drug-delivery systems such as polymers and liposomes. CONCLUSIONS: Although encouraging results have been reported in the literature, there is currently no agent or delivery system that has shown reliable and practical prolongation of local anesthetic effect in humans. There have been several encouraging reports in animals that have shown local anesthetic effects lasting up to several days, but these results must be validated and then performed in human studies before a clinically useful agent is found. Further research is warranted.

Anesthetics, Local↗
PubMed1999

Digital image analysis of erythema development after experimental thermal injury to human skin: effect of postburn topical local anesthetics (EMLA).

UNLABELLED: Local anesthetics inhibit edema and improve circulation in experimental burns. We evaluated the effect of topical local anesthetics on human skin burns in volunteers using computerized color analysis that allowed repeated noninvasive quantitative measurements. A standardized partial-thickness burn (1 cm2) was induced in one forearm of 10 healthy volunteers and in the opposite forearm a week later. The burned areas were treated with lidocaine/prilocaine cream (EMLA; Astra, Sweden) or a placebo cream for 1 h. The experimental skin area was photographed before and 1, 2, 4, and 12 h postburn. Digitized images were evaluated using normalized red-green-blue and Hue-Saturation-Intensity. Differences in erythema between skin treated with EMLA and placebo were not significant during the first 4 h postburn. However, 12 h postburn, a pronounced decrease in the degree of erythema was observed in EMLA-treated skin compared with placebo-treated skin. We conclude that topical local anesthetics administered for 1 h postburn significantly reduces the duration of erythema after a mild thermal injury, which suggests a potential use in clinical practice in the treatment of minor skin burns. IMPLICATIONS: Burn injury constitutes a serious type of tissue damage that activates inflammatory mechanisms, often causing pain, disfiguration, or malfunction. We treated burns using an anesthetic cream and demonstrated a reduction in burn-induced inflammation by using computer-based color image analysis.

Administration, Topical↗
PubMed1984

Local anesthetics in dental practice.

Local anesthetics are the most widely used drugs in dentistry today. Knowledge of the pharmacology and toxicology of these agents will result in their intelligent and judicious use. The choice of local anesthetic should be individualized for each patient. The duration of the dental procedure should be weighed against the duration of action of the local anesthetic; a decision should be made as to whether a vasoconstrictor is needed to prolong its action. However, if the duration of numbness is too long, the possibility of self-mutilation must be considered in certain patients (for example, children and the mentally retarded). In other patients with whom postoperative pain is expected, it may be beneficial to administer a long-acting local anesthetic such as bupivacaine for control of postoperative pain. The total dose of local anesthetic and vasoconstrictor must be determined for each patient based upon body weight; the maximal dosages for each agent should be known. Small children or frail individuals will require below average dosages. The use of a vasoconstrictor may constitute the limiting factor to the total number of local anesthetic cartridges that can be administered safely over a given period of time. Certain medical problems, such as cardiovascular system impairments or hyperthyroidism, may influence the choice of anesthetic and the quantity of vasoconstrictor. An understanding of the physicochemical properties of local anesthetics is also important to a rational process of selection. There are several causes for failure to achieve profound regional anesthesia. These include inflammation and/or infection, anatomic variation, intravascular injection, accessory innervation, and deflection of the needle. Inflammation and infection reduce the efficacy of a local anesthetic by reducing its bioavailability. Local anesthetics with low pKa values (for instance, mepivacaine) are the most effective in this clinical situation. Other causes of inadequate regional anesthesia are primarily related to technique of administration and can be circumvented by the use of the periodontal ligament injection. A comprehensive review of this technique and its application has been presented by the Council on Dental Materials and Equipment of the American Dental Association. Occasionally, a clinician may be unsuccessful at achieving regional anesthesia despite these additional measures. Highly anxious dental patients or patients with a genuine tolerance to local anesthetics normally pose the most problems. Transitional block or threshold block phenomena should also be suspected in these situations.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesia, Dental↗
PubMed1989

[Tachyphylaxis to local anesthetics].

Tachyphylaxis to local anesthetics is defined as decrease in duration, segmental spread, or intensity of a regional block after repeated doses of equal size, i.e. to maintain a given level of effect the dose has to be increased. In contrast, time-dependent variations in pain or circadian changes in the duration of local anesthetic action only simulate the occurrence of tachyphylaxis (pseudotachyphylaxis). Tachyphylaxis appears neither to be linked to structural (ester vs amide) or pharmacological properties of the local anesthetics (short- vs long-acting) nor to technique (surface anesthesia, conduction block, spinal, caudal, or epidural anesthesia, brachial plexus block) or mode of administration (intermittent vs continuous). There is even disagreement about the clinical significance of tachyphylaxis because some authors found it in almost every patient, others less often whereas a third group did not find tachyphylaxis at all. The mechanisms underlying tachyphylaxis are open to debate. Changes in pharmacokinetics (local alterations of disposition and absorption; decrease of perineural pH) and pharmacodynamics (antagonistic effects of nucleotides or increased sodium concentration; increase in afferent input) have been implicated. None of the theoretical considerations presented are strong enough to explain tachyphylaxis. However, results from isolated nerve preparations suggest that pharmacokinetics rather than pharmacodynamics might play a role in the development of tachyphylaxis.

Anesthetics, Local↗
PubMed1997

[Do "lefthanders" make better local anesthetics? The relevance of stereoisomerism in clinical practice as shown by new local anesthetics].

S-Ropivacaine is a new, long-acting amide local anaesthetic. It is the first local anaesthetic to be on the market as a single isomer. Its pharmacodynamic and pharmacokinetic profile is similar to that of bupivacaine. In vitro and in vivo experiments have shown ropivacaine to be less cardiotoxic than bupivacaine. When given epidurally, both local anaesthetics are equally effective in producing sensory block, but motor block seems to be less pronounced in the case of ropivacaine. This pharmacodynamic profile suggests that ropivacaine has a greater margin of safety and should be a valuable candidate in applications where motor blockade is to be avoided, e.g. for postoperative epidural analgesia and for epidural analgesia in obstetrics.

Amides↗
PubMed1999

Percutaneous penetration of local anesthetic bases: pharmacodynamic measurements.

Local anesthetics do not penetrate readily through human skin if applied in their salt form; however, if applied in their base form various effects may be observed, such as a decrease in pricking pain and a change in burning, itch, and thermal sensations. These effects occur after skin penetration and may be attributed to the action of the anesthetics on nociceptors and thermoreceptors, i.e., on C and Adelta nerve fiber respectively. As there is little known about the time course of the pharmacodynamic response of cutaneously applied local anesthetic bases, this study was conducted to characterize various local anesthetics pharmacodynamically by measuring thermal thresholds over time with a thermal sensory analyzer. The results show that the investigated local anesthetics affect thermal thresholds to a different extent, with tetracaine and lidocaine being most efficient. From the response versus time profiles of all eight study subjects various response parameters were obtained: only the cold sensation parameters proved suitable for characterization of the local anesthetics, possibly because cold receptors are located in the epidermis and can easily be reached. Lag times of onset are short and the maximum anesthetic effect is reached within 2-3 h. Cold sensation parameters correlate linearly with the solubility of the local anesthetic bases in medium chain triglycerides and with the drug flux of 50% saturation, indicating that medium chain triglycerides may have similar properties with regard to the local anesthetics solubility as the stratum corneum lipids.

Anesthetics, Local↗
PubMed1988

Inhibition of platelet aggregation by an irreversible local anesthetic.

Three known local anesthetic agents were examined for their ability to inhibit platelet aggregation induced by adenosine diphosphate or epinephrine. Drug-treated platelet-rich plasma samples were filtered through agarose gel to remove free drug, and the ability of the platelets to aggregate was again determined. One of the local anesthetics contained a "one-armed" nitrogen mustard structure and appeared to produce an irreversible inhibition of aggregation. The other two agents gave a block of aggregation that was reversed upon gel filtration.

Adenosine Diphosphate↗
PubMed1976

[Studies on the pharmacodynamics and compatibility of the local anesthetic carticain].

Two local anesthetics were compared with a placebo with regard to subjective tolerance and influence on driving capacity in a double blind test in eight male probands. Neither performance, the ability to respond, reactivity, nor fine motor coordination were reduced or impaired five to sixty minutes after a submucous injection of 3.6 ml of the local anesthetics tested. There were no changes of self-evaluation in the sense of a changed active-passive polarity.

Anesthesia, Dental↗
PubMed1999

Comparison between dopamine transporter affinity and self-administration potency of local anesthetics in rhesus monkeys.

Local anesthetics bind to dopamine transporters and inhibit dopamine uptake in rodent brain. Additionally, local anesthetics are self-administered in rhesus monkeys. The present study determined binding affinities of cocaine and five local anesthetics at dopamine transporters in rhesus monkey brain, and compared binding affinities to published self-administration potencies in rhesus monkeys. The affinity order at dopamine transporters was cocaine > dimethocaine > tetracaine > procaine > or = chloroprocaine > lidocaine. The correlation between dopamine transporter affinities and self-administration potencies was significant. Binding affinities were also determined at sodium (Na2+) channels in rhesus monkey brain. There was not a significant correlation between Na2+ channel affinities and self-administration potencies Local anesthetics with high dopamine transporter and low Na2+ channel affinities were self-administered, whereas those with either high or low affinity at both sites were not consistently self-administered. These data suggest that affinity at dopamine transporters is related to the reinforcing effects of local anesthetics in rhesus monkeys, and Na2+ channel effects may interfere with the reinforcing effect of these drugs.

Anesthetics, Local↗