Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K45/00—Medicinal preparations containing active ingredients not provided for in groups A61K31/00 - A61K41/00
  • A61K45/06—Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/435—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with one nitrogen as the only ring hetero atom
  • A61K31/44—Non condensed pyridines; Hydrogenated derivatives thereof
  • A61K31/445—Non condensed piperidines, e.g. piperocaine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K33/00—Medicinal preparations containing inorganic active ingredients
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K33/00—Medicinal preparations containing inorganic active ingredients
  • A61K33/14—Alkali metal chlorides; Alkaline earth metal chlorides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P23/00—Anaesthetics
  • A61P23/02—Local anaesthetics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/02—Drugs for disorders of the nervous system for peripheral neuropathies

Definitions

• This invention relates to a method of controlling the duration of local anesthesia and a reagent system or kit for inducing and limiting the duration of local anesthesia.
• the present invention relates to anesthesia, especially local anesthetics. More particularly, this invention re- lates to a method for controlling the duration of local anesthesia, and to a reagent system or kit for inducing and limiting or reversing local anesthesia produced.
• Anesthetic agents are pharmacologically active agents that block nerve conduction when applied in therapeutically effective amounts. They can be used for local application, namely to a localized area, for example, by application to the skin or other dermal membrane, or for systemic applica ⁇ tion, e.g., by the intraperitoneal or intravenous routes of administration.
• the anesthetic agent may be applied locally by injec ⁇ tion, ointments, jellies, topical solutions and suspensions or other forms known for topical administration.
• Local anesthetics generally are esters or amides of benzoic acid, typically administered as an acid addition salt in dosages known to those skilled in the art.
• anesthesia involves injection of anesthetic agents including roughly 2 to 3% lidocaine, 2 to 3% mepivacaine, 0.5% marcaine or 3 to 4% prilocaine, usual- ly administered in aqueous solution in the form of a water- soluble acid-addition salt, typically the hydrochloride salt.
• vasoconstricting agents such as epinephrine, phenylphrine or levonordenphedrine may be administered conco itantly or separately with the local anesthetic agent in order to prolong the duration of the local anesthesia, reportedly by constriction of blood ves ⁇ sels, resulting in prolongation of the contact of the anesthetic with the nerve.
• Aqueous Lidocaine hydrochloride in sodium bicarbonate has been used in spinal and epidural anesthesia to speed up the onset of anesthesia to reduce the burning upon injec ⁇ tion and to lengthen the duration of the action.
• the local anesthesia may last longer than needed. This is debilitat- ing and restrictive to the patient's normal activity.
• a local anesthesia can be reversed or limited by the subse ⁇ quent administration of an inorganic or organic salt re ⁇ versing agent in a fluid which is preferably an aqueous solution having a pH equal to or greater than about pH 7, preferably a pH of about 7 to about 8.5.
• the upper limit of the pH is not critical except that, in practice, the upper limit of the pH is affected by the nature of the salt, and any buffer, the concentration of base used to adjust the pH.
• This invention thus provides a method of limiting duration of local anesthesia or reversing the anesthesia.
• This method is comprised of the steps of (a) administering an effective amount of an anesthetic agent to a local area of the subject; and (b) subsequently administering an ef ⁇ fective amount of a reversing agent which is an inorganic or organic salt in a fluid having a pH equal to or greater than pH 7.
• the reversing agent limits the duration of anesthesia activity.
• the reversing agent can be in buffered solution or the anesthetic agent can be applied in conjunction with a vasoconstrictor to prolong the anesthetic action, or both.
• This invention also includes a reagent system for use in the method which comprises (a) first container contain ⁇ ing an anesthetic agent and (b) a second container contain ⁇ ing a reversing agent which is an inorganic or organic salt in a fluid having a pH of at least about 7, and preferably about pH 7 To 8.5.
• the reversing agent is preferably administered in the form of a pharmaceutically acceptable pyrogen free mixture, preferably an aqueous solution in a concentration of about 4.0% to about 8.4% by weight, though concentrations sub- stantially greater than 8.4% and substantially less than 4.0% will also reverse the duration of the local anesthe ⁇ sia.
• the amount of reversing agent administered depends on the size and body weight of the pa ⁇ tient, the area to be anesthetized, the route of adminis- tration and the concentration of anesthetic agent, but is typically approximately 1.8 to 6.0 cubic centimeters of a mixture of the foregoing concentration.
• the inorganic or organic salt of the reversing agent is preferably the salt of a weak acid, and strong base, or weak base.
• the method and reagent can optionally be used in con ⁇ junction with a vasoconstrictor to prolong the duration of the action.
• the anes- thetic agent is lidocaine or mepivacaine, preferably in the form of the hydrochloride acid-addition salt, and the re ⁇ versing agent is sodium bicarbonate, calcium gluconate or calcium chloride.
• the method of this invention relates to limiting the duration of local anesthesia or reversing anesthesia in a subject, comprising the steps of (a) administering an effective amount of an anesthetic agent to a local area of a subject to produce anesthesia; and
• subject according to the present invention is intended to include all warm-blooded mammals, preferably humans.
• anesthesia agent refers to non- toxic and for injection, pyrogen free substance known to be suitable for inducing local anesthesia in warm-blooded mammals and includes a large class of known compounds which generally are esters or amides of benzylic acid deriva ⁇ tives, typically administered for convenience in the form of an aqueous solution of an acid addition salt.
• Anesthe ⁇ tics useful for this purpose include lidocaine, bupivi- caine, chloroprocaine, editocaine, mepivacaine, prilocaine, procaine and tetracaine, all of which are commercially supplied for use as local anesthetics in the form of the hydrochloride acid-addition salt typically in aqueous solu ⁇ tion.
• Other useful amines or amides suitable as local anesthetics include benoxinate, proparacaine, dibucaine, diclonine and pramoxine.
• Less suitable are local anesthe ⁇ tics of low solubility including benzocaine and small quan ⁇ tities of the toxins tetrodotoxin and saxitoxin. Also less suitable because of its addictive properties is cocaine.
• local anesthesia is commonly understood by the skilled artisan to mean an anesthesia having an effect only to one spot or part and not general.
• anesthe- tic agent amounts known to be effective for topical application. Such amounts depend on the agent to be used, the location of administrat on and the form of the anesthe ⁇ tic.
• lidocaine is commercially available as the hydrochloride and is used in preparations in about 0.5 to about 20% by weight, volume, some with and some without epinephrine for infiltration, about 1 to 2% for block and about 5% for topical mucosal anesthesia.
• Bupivicaine is used commercially as the hydrochloride in solutions from about 0.25 to about 0.75%; chloroprocaine is used as the hydrochloride in solutions of about 1 to 3%.
• Ediocaine is used as the hydrochloride in solutions of about 1 to 2%.
• Mepivicaine is used in solutions of about from 1 to 3% with or without levonordenphedrine as a vasoconstrictor.
• Prilocaine is used as the hydrochloride in solution at about 4% with or without epinephrine as a vasoconstrictor.
• Procaine is used as the hydrochloride in solutions of about 0.25 to 0.5% for infiltration, 0.5% to 2% for peripheral nerve block and 10% for spinal anesthesia.
• Tetracaine is used in solutions as the hydrochloride of about 5% as an ointment and about 2% for application to the mucous mem ⁇ branes or throat.
• Tetracaine for injection is available in solutions or ampules containing the dry salt, as well as ointments of 5% and creams of 1%.
• non-toxic used here means that the agent should not cause any permanent damage to the nerve struc ⁇ ture.
• its systemic toxicity should be low because the anesthetic agent is eventually absorbed from the site of application.
• anesthetic agent is preferably not irritating to the tissue to which it is applied.
• pyrogen free when applied to the agents used for injection means that the mixture in question does not contain substances known to cause a pyrogenic response. Pyrogens can be removed from any mixtures by methods known in the art.
• the local anesthetic is administered in a solution from about 0.5 to 5% and in other mixtures of up to 20% or 30% or more by weigh /volume.
• the amount admin ⁇ istered for any local anesthesia depends on the route or locale for administration.
• the amount used generally is no more than 6 cubic centimeters ( "cc" ) of a 2% solution.
• the salt is administered in a concentration of from about 2% to 10% in an amount of about 0.5 to 6cc.
• the anesthesia is applied locally in known ways in ⁇ cluding surface anesthesia, infiltration, field block anes- thesia, a nerve block anesthesia, intravenous regional anesthesia, spinal anesthesia and epidural anesthesia.
• Surface anesthesia involves topical application to the . mucous membranes such as those found in the nose, mouth, throat, tracheo-bronchial tree, esophagus and the genito- urinary tract.
• Infiltration anesthesia consists of an injection of the anesthetic directly into the tissue to be incised or mechanically stimulated. This anesthesia can be superficial so as to include only the skin or include deeper structures including intraabdominal organs when they are infiltrated.
• Field block anesthesia is produced by subcutaneous injection of the local anesthetic to inter ⁇ rupt nerve transmission proximal to the site to be anesthe- tized.
• Nerve block anesthesia involves injection of the anesthetic into or about individual or peripheral nerves or nerve plexus to produce greater areas of anesthesia than the previous methods.
• Intravenous regional anesthesia involves injection of the solution into a vein of an ex- tremity previously exsanguinated and kept exsanguinated.
• Spinal anesthesia involves injection of the anesthetic into the lumbar subarachnoid space.
• Epidural anesthesia involves injection of the anesthetic into the epidural space.
• the anesthesia can then be reversed or limited by the adminis ⁇ tration of an effective amount of a non-toxic, preferably pyrogen free inorganic or organic salt reversing agent in a fluid having a pH equal to or greater than about pH 7, preferably a pH of about 7 to about 9 and more preferably a pH of about 7 to 8.5.
• the upper limit of the pH of the reversing agent is not critical. However, in practice, the upper limit of pH is determined by the nature of the salt, any buffer or base present, and the concentration of the foregoing. Additionally, the sensitivity of the skin to basic substances is such that a pH of not more than 10 and preferably not more than 9 is preferred.
• organic or organic salt when used with reference to the reversing agent refers to a non-toxic, preferably water soluble, salt in a preferably pyrogen free mixture which is capable of being adjusted to a pH of at least 7 and preferably at least about a pH of 7.0 and more preferably a pH of 8.
• the salt is preferably an alkali or alkaline earth metal salt of an inorganic and organic acid.
• the salt should either be the salt of a weak acid and strong base, or of a weak acid and a weak base. Typical cations of the salt are sodium, potassium, calcium and magnesium.
• Typical anions are monovalent inor ⁇ ganic anions such as fluoride, bromide and chloride; multi- valent organic anions such as carbonate, hydrogen carbon ⁇ ate; and multivalent inorganic anions such as sulfate and phosphate.
• Non-toxic inorganic anions of organic acids include anions of mono-like and dibasic organic acids such as the acetate, gluconate and monoordicarboxylic acids.
• Preferred reversing agents are sodium bicarbonate, calcium gluconate and calcium chloride.
• the salt in order to maintain the salt at the desired pH, can be administered in a buffer which will maintain the mixture containing the salt at a pH of at least 7 and preferably a pH of at least 7.8 and more preferably a pH from about 7 to 8.5.
• Typical buffers are those known in the art and include inorganic and organic buffers including phosphate, citrate, bicarbonate and the like.
• affecting the duration of local anesthesia and “to reverse or limit” the duration of anesthesia means that the administration of the inorgan ⁇ ic or organic salt serves to significantly reduce the duration of anesthesia over that which would occur in the absence of the reversing agent. This affecting of the duration of anesthesia may involve merely shortening the duration of action or totally reversing the anesthesia upon the administration.
• the amount of reversing agent adminis ⁇ tered determines whether the anesthesia is limited or to ⁇ tally reversed. The amount of reversing agent necessary is dependent on whether limitation or reversal is desired, the half life of the anesthetic agent by the route of adminis ⁇ tration used and the timing of the administration of the reversing agent. Appropriate dosages in amounts will be apparent to one skilled in the art or can be determined by simple routine experimentation.
• an amount necessary to reverse or limit the anesthesia that has been induced refers to an amount necessary to reverse or limit the anesthesia that has been induced. As indicated, this amount can be determined by a person skilled in the art and typically is a molar amount or concentration at least equal to or less than the molar amount of the anes ⁇ thetic agent that has been injected or the remaining unme- tabolized anesthetic agent in the area of application.
• the anesthetic agent can be administered concomitantly with a vasoconstrictor to pro ⁇ long the duration of action.
• vasoconstrictor used here means an agent capable of causing constriction of blood vessels including various sympathomimetic drugs such as epinephrine, norepinephrine, levonordenphedrine and dopamine.
• epinephrine is administered in a dilution of 1:100,000 mixed with a solution of lidocaine and sup ⁇ plied in 1.8 cc capsules.
• the reversing salt is preferably administered in a non-toxic, pryogen free fluid mixture.
• fluid means any vehicle suitable for topical administration including solutions in suspen ⁇ sions for injections, ointments, jellies, topical solutions in suspensions and other forms known for topical adminis ⁇ tration.
• anesthetic agent is adminis- tered by injection
• the reversing solution to achieve its optimal effectiveness should also be administered by injection.
• the fluid of the reversing solution is conveniently water.
• the reversing agent is administered by the same means and route as the anesthesia.
• the salt is present, depending upon the solubility of the salt, in an amount of approximately 1 molar in aqueous solution.
• a 1 molar, or meq/ml (84 mgs/ml) solution has a pH of about 7.8.
• Such a solution is conveniently contained in an individual dosage unit of a size of approximately 1.8 cc where application to the oral cavity is concerned.
• the pH of the reversing mixture is equal to or greater than about 7 and more preferably about 7 to 8.5 or 9.0.
• Use of a reversing salt having a pH of greater than 9 tends to be less effective and thus is not as desirable as use of a reversing solution at a pH of about 7 to 8.9.
• the reversing mixture can be a simple mixture of a vehicle and the salt.
• the reversing solution can contain a buffer to maintain the pH at the desired level.
• the amount of the solution used is about 0.6 to 6.6 cc when the reversing agent is present in a concentration of 4.0 to 8.4% by weight.
• the re ⁇ versing agent is administered at a concentration of 2% to 10% by weight/volume in an amount of about 0.5 to 6cc.
• the reversing agent is sodium bi- carbonate in a solution of about 8% by weight and having a pH of about 7 to 9.
• Another feature of this invention is a reagent system for use in inducing and reversing the local anesthesia.
• Such system conveniently includes a container such as a carpule which contains the local anesthetic agent, a con ⁇ tainer or carpule of sodium bicarbonate for reversing the anesthesia, and optionally a container or carpule contain- ing other substances to be used in conjunction therewith, for example, calcium ion for relieving any conduction block produced by the anesthetic.
• the system may alternatively include other known containers suitable for delivering their contents to the site of anesthesia.
• the reagent system of the invention is comprised of carpule containing the local anesthetic and a vasoconstrictor and a carpule containing sodium bicarbonate solution for reversing the local anesthesia.
• the solutions for use in this invention can contain additional additives known for use in sterile pharmaceuti ⁇ cal solutions and suspensions including, but not limited, to stabilizers, antimicrobial agents, suspending agents and other ingredients known to enhance the use and shelf life of the products of this invention.
• Experiment Design Subjects received injections to right or left arms at several sites.
• the first injection usually 0.5 cc - 0.6 cc was followed by a second injection of the same volume to the same site as the initial injection.
• the second injec ⁇ tion was placed within 5 to 20 minutes of the first in ec- tion.
• Pin prick tests were done every 5 minutes until sensa ⁇ tion returned at all sites (usually by 6 hours) . Tests were conducted double blind.
• Solution B was positive after 1 hour 25 minutes or reversal achieved in less than half the control time.
• Solution B was positive after 1 hour or reversal achieved in less than half the control time.
• Solution B was positive after 1 hour and 55 minutes resulting in a reversal of about roughly one-half time than the control time.
• Solution B was positive after 1 hour 20 minutes or resulting in a reversal in half the time of the control.
• Solution B achieved a faster reversal than Solu ⁇ tion A. Both Solution B and Solution A achieved reversal in about one third to one half less time than the control (Solution E) .
• Solution C achieved a slightly faster reversal than Solution B. Both Solution C and Solution B achieved reversal in less time than the control (Solution E) .
• Solution C achieved the fastest reversal.
• Solutions B and D achieved a reversal in greater time than the control solution (E) .
• Solution C achieved the fastest reversal. Solutions A, B and D achieved a faster reversal than the control Solution E.

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• 1991
  • 1991-12-23 US US07/812,409 patent/US5192527A/en not_active Expired - Lifetime
• 1992
  • 1992-06-26 WO PCT/US1992/005336 patent/WO1993000932A1/en not_active Ceased
  • 1992-06-26 JP JP50224593A patent/JP3578455B2/ja not_active Expired - Lifetime
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