Anesthesia mepivacaine

Mepivacaine (carbocaine, polocaine) is an intermediate-acting amino amide pharmacologically similar to lidocaine. Mepivacaine, however, is more toxic to the neonate and thus is not used in obstetrical anesthesia. Mepivacaine is not effective as a topical anesthetic. 

The choice of local anesthetic and the amount and concentration administered are determined by the nerves and the types of fibers to be blocked, the required duration of anesthesia, and the size and health of the patient. For blocks of 2-4 hours, lidocaine (1-1.5%) can be used in the amounts recommended above (see Infiltration Anesthesia ). Mepivacaine (up to 7 mg/kg of a 1-2% solution) provides anesthesia that lasts about as long as that from lidocaine. Bupivacaine (2-3 mg/kg of a 0.25-0.375% solution) can be used when a longer duration of action is required. Addition of 5 pg/mL epinephrine slows systemic absorption and, therefore, prolongs duration and lowers the plasma concentration of the intermediate-acting local anesthetics. 

Mepivacaine hydrochloride [1722-62-9] similar in profile to Hdocaine, is used for infiltration, peripheral nerve blocks, and extradural anesthesia. It appears to be less toxic than Hdocaine in adults but more toxic in newborns. The duration of action is longer than that of Hdocaine because of its lower vasodilator activity. Mepivacaine has Htde topical activity. 

Spinal anesthesia Spinal anesthesia is the introduction of local anesthetics directly into the spinal fluid, which causes a sympathetic blockage, or loss of feeling as well as muscle relaxation resulting from the interaction of anesthetic with every spinal nerve tract. This method is used during major surgical interventions. As a rule, lidocaine, mepivacaine, and bupivacaine are used for this purpose. 

Epidural anesthesia This term is understood to be an introduction of local anesthetic into the spinal cord membrane of the intervertebral space. It is used during obstetrical and gynecological interventions that do not require a fast development of anesthesia. Drugs such as lidocaine, mepivacaine, bupivacaine, ethidocaine, and chloroprocaine are used for this purpose. 

Amide-type agents include articaine, lidocaine, bupivacaine, prilocaine, mepivacain and ropiva-caine. These are metabolized in the liver by microsomal enzymes with amidase activity. The amide group is preferred for parenteral and local use. If by accident rapidly administered intravascularly these agents, especially bupivacaine but also lidocaine, can produce serious and potentially lethal adverse effects including convulsions and cardiac arrest. They can more easily accumulate after multiple administrations. Intravenous lidocaine is sometimes used for regional anesthesia, for infiltration procedures, for the induction of nerve blockade and for epidural anesthesia. However, it is also used as an antiarrhythmic. Bupivacaine is a long-acting local anesthetic used for peripheral nerve blocks and epidural anesthesia. 

Clinical use Mepivacaine has been employed for all types of infiltration and conduction nerve block anesthesia using solutions of 1.0 and 1.5 % lasting for 1.5 to 3 h. Epidural anesthesia with 2.0 % mepivacaine has a rapid onset with a dense motor block. Hyperbaric solutions of mepivacaine have also been used for spinal anesthesia (Tetzlaff, 2000). Mepivacaine has been used for topical applications, but other LA such as lidocaine are more effective. 

PURPOSE AND RATIONALE Surface anesthesia is used to anesthetize the cornea and conjunctiva of the eye and the mucous membranes in the mouth. The classical pharmacological test is the blockade of the rabbit corneal reflex as described by Regnier (1923) that has become a standard test method for evaluating local anesthetics (FuBganger and Schaumann 1931 Ther 1953a Quevauviller 1971 Muschaweck et al. 1986). These pharmacological methods are only partially suitable to determine the irritancy potential of local anesthetic on mucus membranes. Luduena et al. (1960) compared the mucus membrane irritancy of mepivacaine and lidocaine by the eye irritation method according to Hoppe (1950) and Draize et al. (1944). 

Iontophoresis of mepivacaine and lidocaine with epinephrine have been reported in human cadaver bladders and in clinical trials by Lugnani et al. [41], The study reported that the active electrode must be sited close to the geometric center of the bladder cavity in order to anesthesize the entire bladder. Siting the electrode close to the wall resulted in anesthesia of only that section of the bladder. 

Two to three injection sites may be needed to provide adequate anesthesia. For minor surgical procedures of the eyelid, the volume of anesthetic required would be far less than the maximum dose of most local anesthetics (e.g., procaine, lidocaine, and mepivacaine)—approximately 500 mg as a 1% or 2% solution.A ring block or field block may be used to anesthetize around the area of the surgical site in a circumferential manner without injecting... 

Injection directly into the cerebrospinal fluid (CFS) ensures complete CNS bioavailability for drugs that cannot cross the blood-brain barrier. This dosage route is used to treat serious CNS infections such as meningitis and ventriculitis, and with such agents as mepivacaine and prilocaine for spinal anesthesia. Drugs injected intrathecally initially distribute into approximately 140 ml of CSF, thus producing high concentrations in the CNS with low risk of systemic toxicity. 

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). 

The incidence of transient radicular irritation with two different local anesthetics used for single-dose spinal anesthesia has been studied in 60 ambulatory patients given spinal anesthesia for knee arthroscopy (235). None of those who were given 1.5% mepivacaine 45 mg developed transient radicular irritation. Six of those given 2% lidocaine 60 mg developed transient radicular irritation, but all symptoms resolved by 1-5 days. The difference between the two groups was significant. 

In a careful meta-analysis, 29 randomized, controlled studies of the incidence of transient radicular irritation were identified (243). Lidocaine and mepivacaine were identified as the two local anesthetics that most commonly cause transient radicular irritation, while prilo-caine, bupivacaine, and ropivacaine had the lowest incidences. Owing to insufficient data, definitive statements could not be made about the effects of the baricity of the local anesthetic, the concentration, and the effect of vasoconstrictors, although all these factors seemed not to be relevant. With regard to intrathecal ropivacaine, the incidence in the formal studies was zero. However, there has been one previous report after intrathecal administration, and one report of transient radicular irritation following epidural anesthesia with ropivacaine the symptoms resolved within 24 hours (244). 

A 44-year-old man developed transient pain in the buttocks and thighs 4 hours after 4% hyperbaric mepivacaine had been used to provide anesthesia for knee arthroscopy (258). The sjmptoms resolved after 2 days. 

Urinary retention as a true transient neurological symptom developed after accidental total spinal anesthesia with mepivacaine, which is often considered to be the best agent for intrathecal anesthesia, owing to its low incidence of transient radicular irritation (268). 

Two cases of transient blindness after subconjunctival injection of 2% mepivacaine 2 ml were reported in patients with advanced refractory glaucoma undergoing diode laser cyclophotocoagulation (339). The authors hypothesized that in patients with advanced optic neuropathy, even subconjunctival anesthesia can result in optic nerve block. 

Salmela L, Aromaa U. Transient radicular irritation after spinal anesthesia induced with hyperbaric solutions of cerebrospinal fluid-diluted lidocaine 50 mg/ml or mepivacaine 40 mg/ml or bupivacaine 5 mg/ml. Acta Anaesthesiol Scand 1998 42(7) 765-9. 

Liguori GA, Zayas VM. Repeated episodes of transient radiating back and leg pain following spinal anesthesia with 1.5% mepivacaine and 2% lidocaine. Reg Anesth Pain Med 1998 23(5) 511-15. 

Liguori GA, Zayas VM, Chisholm MF. Transient neurologic symptoms after spinal anesthesia with mepivacaine and lidocaine. Anesthesiology 1998 88(3) 619-23. 

Adachi Y, Watanabe K, Uchihashi Y, Sato T. [Urinary retention as a transient neurologic symptom after accidental total spinal anesthesia with mepivacaine hydrochloride..] Masui 1999 48(9) 1009-10. 

Hjrperbaric mepivacaine has also been implicated in causing transient radicular irritation after spinal anesthesia, of the same order of magnitude as lidocaine (3,4). Three cases of transient radicular irritation have been reported after spinal anesthesia with isobaric 2% mepivacaine (5). 

Griebenow R, Saborouski F, Matthes H, Wald-Oloumier H. EKG-Veranderungen bein Infiltrationsanesthesie mil Mepivacain. [EGG changes after spinal anesthesia using mepivacaine.] Intensivmed 1979 16 163. 

Before a fuU-face phenol peel, the patient is always put on a drip, electrocardiographic monitoring, pulse oximeter and blood pressure monitor. The doctor has everything he needs at his disposal in case of any allergic, vagal or other reactions. Although bupivacaine, ropivacaine or mepivacaine can be employed for FNB, these products should not be used for the reasons set out above, and anesthesia should consist of FNB with lidocaine without adrenaline and with deep sedation. 

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