Tetracaine Mepivacaine

Presentation Transient radicular irritation causes transient pain in the back, buttocks, and lower extremities, without formal neurological signs or symptoms. It can follow single-dose intrathecal anesthesia. Lidocaine has been reported as the predominant culprit. However, transient radicular irritation has also been reported with bupivacaine, mepivacaine, tetracaine, and prilocaine. Osmolarity, the addition of dextrose, and speed of injection do not contribute, and even reducing the concentration of hdocaine does not alter the incidence (220,221). 

Na+ Anticonvulsant drugs Class I antiarrhythmics Diuretic drugs Local anesthetic drugs Carbamazepine, phenytoin, valproic acid lA Disopyramide, procainamide, quinidine IB Lidocaine, mexiletine, phenytoin, tocainide IC Encainide, flecainide, propafenone Amiloride Bupivacaine, cocaine, lidocaine, mepivacaine, tetracaine... 

Some other anesthetics with similar structures are prilocaine, tetracaine, ropivacaine, bupivacaine, chloroprocaine, and mepivacaine ... 

The local anesthetics can be broadly categorized on the basis of the chemical nature of the linkage contained within the intermediate alkyl chain group. The amide local anesthetics include lidocaine (7.5), mepivacaine (7.6), bupivacaine (7.7), etidocaine (7.8), prilocaine (7.9), and ropivacaine (7.10) the ester local anesthetics include cocaine (7.11), procaine (7.12), benzocaine (7.13), and tetracaine (7.14). Since the pharmacodynamic interaction of both amide and ester local anesthetics with the same Na" channel receptor is essentially idenhcal, the amide and ester functional groups are bioisosterically equivalent. However, amide and ester local anesthetics are not equal from a pharmacokinetic perspective. Since ester links are more susceptible to hydrolysis than amide links. 

The choice of local anesthetic for infiltration, peripheral nerve blocks, and central neuraxis (spinal/epidural) blockade is usually based on the duration of action required. Procaine and chloroprocaine are short-acting lidocaine, mepivacaine, and prilocaine have an intermediate duration of action and tetracaine, bupivacaine, levobupivacaine, and ropivacaine are long-... 

Because of cocaine s toxicity and addictive properties, a search began for synthetic substitutes for cocaine. In 1905, procaine was synthesized and became the prototypic local anesthetic for half a century. Newer derivatives include mepivacaine and tetracaine (Figure 13.1). Briefly, the SAR of local anesthetics revolves around their hydrophobicity. Association of the drug at hydrophobic sites, such as the sodium channel, is believed to prevent the generation and conductance of a nerve impulse by interfering with sodium permeability (i.e., elevating the threshold for electrical excitability). 

Henn Brattsand (1966), using the trypan-blue test, reported that intradermal irritancy of mepivacaine in rabbits was less than with tetracaine, whether the solution contained adrenaline or not. 

Luduena FP, Hoppe JO (1952) Local anaesthetic activity, toxicity and irritancy of 2-alkoxy analogs of procaine and tetracaine. J Pharm Exp Ther 104 40-53 Luduena FP, Hoppe JO, Coulston F, Drobeck HP (1960) The pharmacology and toxicology of mepivacaine, a new local anesthetic. Toxicol Appl Pharmacol 2 295-315 Luduena FP, Bogado EF, Tullar BF (1972) Optical isomers of mepivacaine and bupivacaine. Arch Int Pharmacodyn 200 359-369... 

The tests allow judgement of the propensity of local anesthetics to induce symptoms of hepatic porphyria. The local anesthetics lidocaine, bupivacaine, etido-caine, mepivacaine, prilocaine and pyrocaine belong to this group, but procaine, butacaine, oxybuprocaine, proxymethacaine and tetracaine had no (or very slight) porphyrinogenic effect. 

Some distinction must be made between the main groups of local anesthetics as to the frequency of complications. Hypersensitivity reactions, for example, are relatively less common with the aminoamides, such as bupivacaine, cinchocaine, etidocaine, lidocaine, mepivacaine, prilocaine, and ropivacaine, than with the amino-esters. However, the systemic toxic effects of individual local anesthetics differ bupivacaine, cinchocaine, and tetracaine are the most toxic. Furthermore, the individual characteristics of the patient (for example age, sex, body weight, and cardiac, renal, and hepatic function) are important (SEDA-17,134). 

A 46-year-old woman had an epidural placed at L4/5 (259). As there was insufficient block 20 minutes after injection of 300 mg mepivacaine, the epidural catheter was removed and an intrathecal injection of 0.5% tetracaine 2 ml dissolved in 5% glucose was performed. She was then placed in the hthotomy position for 30 minutes. One day postoperatively she developed pain and numbness in her left leg, and the numbness spread to the lower back, buttocks, and thighs. The symptoms disappeared after 4 days. 

Takenami T, Kondou Y, Kimotsuki H, Okamoto H, Hoka S. A case of transient neurologic symptoms following epidural mepivacaine and spinal tetracaine. J Anesth 2002 16(4) 336-8. 

Also analyzed acebutolol, acepromazine, acetaminophen, acetazolamide, acetophenazine, albuterol, amitriptyline, amobarbital, amoxapine, antipsrrine, atenolol, atropine, azata-dine, baclofen, benzocaine, bromocriptine, brompheniramine, brotizolam, bupivacaine, buspirone, butabarbital, butalbital, caffeine, carbamazepine, cetirizine, chlorqyclizine, chlordiazepoxide, chlormezanone, chloroquine, chlorpheniramine, chlorpromazine, chlorpropamide, chlorprothixene, chlorthalidone, chlorzoxazone, cimetidine, cisapride, clomipramine, clonazepam, clonidine, clozapine, cocaine, codeine, colchicine, qyclizine, (yclo-benzaprine, dantrolene, desipramine, diazepam, diclofenac, diflunisal, diltiazem, diphenhydramine, diphenidol, dipheno late, dipyridamole, disopyramide, dobutamine, doxapram, doxepin, droperidol, encainide, ethidium bromide, ethopropazine, fenoprofen, fentanyl, flavoxate, fluoxetine, fluphenazine, flurazepam, flurbiprofen, fluvoxamine, fii-rosemide, glutethimide, glyburide, guaifenesin, haloperidol, homatropine, hydralazine, hydrochlorothiazide, hydrocodone, hydromorphone, hydro g chloroquine, hydroxyzine, ibuprofen, imipramine, indomethacin, ketoconazole, ketoprofen, ketorolac, labetalol, le-vorphanol, lidocaine, loratadine, lorazepam, lovastatin, loxapine, mazindol, mefenamic acid, meperidine, mephenytoin, mepivacaine, mesoridazine, metaproterenol, methadone, methdilazine, methocarbamol, methotrexate, methotrimeprazine, methoxamine, methyl-dopa, methylphenidate, metoclopramide, metolazone, metoprolol, metronidazole, midazolam, moclobemide, morphine, nadolol, nalbuphine, naloxone, naphazoline, naproxen, nifedipine, nizatidine, norepinephrine, nortriptyline, oxazepam, oxycodone, oxymetazo-line, paroxetine, pemoline, pentazocine, pentobarbital, pentoxifylline, perphenazine, pheniramine, phenobarbital, phenol, phenolphthalein, phentolamine, phenylbutazone, phenyltoloxamine, phenytoin, pimozide, pindolol, piroxicam, pramoxine, prazepam, prazosin, probenecid, procainamide, procaine, prochlorperazine, procyclidine, promazine, promethazine, propafenone, propantheline, propiomazine, propofol, propranolol, protriptyline, quazepam, quinidine, quinine, racemethorphan, ranitidine, remoxipride, risperidone, salicylic acid, scopolamine, secobarbital, sertraline, sotalol, spironolactone, sulfinpyrazone, sulindac, temazepam, terbutaline, terfenadine, tetracaine, theophylline, thiethyl-perazine, thiopental, thioridazine, thiothixene, timolol, tocainide, tolbutamide, tolmetin, trazodone, triamterene, triazolam, trifluoperazine, triflupromazine, trimeprazine, trimethoprim, trimipramine, verapamil, warfarin, xylometazoline, yohimbine, zopiclone... 

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