Anesthesia prilocaine

In eight episodes of toxic methemoglobinemia in seven premature infants after the combination of caudal anesthesia (prilocaine 5.4—6.7 mg/kg) and Emla cream (prilocaine 12.5 mg) for herniotomy, the highest methe-moglobin concentration 5.5 hours after anesthesia was 31% (86). All the infants were sjmptomatic, with mottled skin, pallor, cyanosis, and poor peripheral perfusion. The most severe symptoms occurred at 3-8 hours and disappeared within 10-20 hours. The authors stressed the importance of recognizing the poor tolerance of premature infants to methemoglobinemia and that whereas topical prilocaine is relatively safe, caudal administration is not. 

Similar to Voltaren" Emulgel, oily droplets of an eutectic mixture of lidocaine and prilocaine are dispersed in a hydrogel to provide local anesthesia to the skin for injections and siugical treatment (Emla cream). A further possibility is the dermal administration of a liposome dispersion as a spray (Heparin PUR ratiopharm Spriih-gel "). After administration, water and isopropylic alcohol evaporate partially resulting in an increase of concentration and in a transition from the initial liposome dispersion into a lamellar liquid crystal [32]. The therapeutic effect appears to be influenced favorably by the presence of lecithins rather than by the degree of liposome dispersion. 

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. 

EMLA cream (lidocaine 2.5% and prilocaine 2.5%) consists of a eutectic mixture of focal anesthetics. It is used to provide topical anesthetic to intact skin. Other topical preparations are effective only on mucosal surfaces. EMLA has been shown to reduce pain on venipuncture and provide substantial anesthesia for skin graft donor sites. No significant local or systemic toxicity has been demonstrated. 

Clinical use Topical anesthesia is easily achieved using an eutectic mixture of the LAs prilocaine and lidocaine (EMLA, see Lidocaine). 

With infiltration of 0.5 to 1.0% prilocaine local anesthesia with a duration of 1 to 2 h is established. Peripheral nerve block is achieved with 1.5 to 2.0 % with a duration of 2 to 3... 

Clinical use Tetracaine is employed by ophthalmologists for surface anesthesia as a 0.5 % solution and by endoscopists for anesthesia of mucous membranes including airways as a 2.0 % solution. For topical anesthesia, a 4.0 % cream of tetracaine can also be used, which is, however, less effective than a lidocaine/prilocaine cream in preventing venipuncture-induced pain in children (van Kan et al., 1997). A combination of tetracaine with adrenaline and cocaine (TAC) is widely used for repair of... 

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. 

Two reviews have highlighted the fact that the degree and incidence of neurological damage after dental anesthesia is probably underestimated. Some drugs, such as articaine and prilocaine, seem to cause a higher incidence of paresthesia than others (SEDA-20,124). 

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). 

When 90 patients received spinal anesthesia for gynecological procedures with 2% hdocaine, 2% prUocaine, or 0.5% bupivacaine (all 2.5 ml in 7.5% glucose), nine of the 30 patients who received lidocaine had transient radicular irritation, defined as pain or dysesthesia in the legs or buttocks, compared with none of the 30 patients who received bupivacaine (236). The symptoms resolved within 48 hours. One of the 30 patients who received prilocaine had transient radicular irritation that lasted for 4 days. 

Systemic toxic reactions are the most common complications of intravenous regional anesthesia, and they occur soon after the tourniquet is released. In cases of early accidental tourniquet release or rupture, deaths have resulted prilocaine seems to be the safest agent for this technique (271). 

Hampl KF, Heinzmann-Wiedmer S, Luginbuehl I, Harms C, Seeberger M, Schneider MC, Drasner K. Transient neurologic symptoms after spinal anesthesia a lower incidence with prilocaine and bupivacaine than with lidocaine. Anesthesiology 1998 88(3) 629-33. 

Kilic I, Kalayci O. Methemoglobinemia due to prilocain local anesthesia. Doga Turk J Med Sci 1993 19. 

Prilocaine, a local anesthetic (4% with 1 200,000 epinephrine in 1 to 8 mL dental cartridge), is indicated for local anesthesia by nerve block or infiltration in dental procedures. 

Why would prilocaine be a good choice for dental anesthesia ... 

The introduction of a eutectic mixture of lidocaine (2.5%) and prilocaine (2.5%) (EMLa) bridges the gap between topical and infiltration anesthesia. The efficacy of this combination lies in the fact that the mixture of prilocaine and lidocaine has a melting point less than that of either compound alone, existing at room temperature as an oil that can penetrate intact skin. EMLA cream produces anesthesia to a maximum depth of 5 mm and is applied as a cream on intact skin under an occlusive dressing, for procedures involving skin and superficial subcutaneous structures (e.g., venipuncture and skin graft harvesting). EMLA must not be used on mucous membranes or abraded skin, as rapid absorption across these surfaces may result in systemic toxicity. 

Contact dermatitis with prilocaine has been reported after tumescent anesthesia [47 ]. 

A 40-day-old boy developed cyanosis after receiving local anesthesia with prilocaine [72 ]. He had severe methemoglobinemia (44%) and his cyanosis resolved after intravenous methylthioninium chloride. 

A 69-year-old woman developed prilocaine-induced methemoglobinemia after endovenous laser ablation during which prilocaine 1200 mg was used for tumescent anesthesia of four truncal veins [76 ]. She developed the signs of methemoglobinemia and required treatment with ascorbic acid and methylthioninium chloride. She recovered within 24 hours and was discharged without sequelae. 

Spornraft-Ragaller P, Stein A. Contact dermatitis to prilocaine after tumescent anesthesia. Dermatol Surg 2009 35(8) 1303-6. 

Peker E, Cagan E, Dogan M, Aktar F, Bektas S, Kirimi E, Ceylan A. Methemoglobinemia due to local anesthesia with prilocaine for circumcision. J Paediatr Child Health 2010 46 362-3. 

Local anesthesia refers to injecting anesthetic into the skin to temporarily numb a small area so that a minor procedures can be done painlessly. This type of anesthetic is normally used for stitching small lacerations or for dental procedures. Drugs commonly used as local anesthetics include lidocaine and prilocaine. 

One of the first uses of local anesthetics (LA) for anesthesia was in the late nineteenth century with William Halsted reporting a mandibular block and brachial plexus block using cocaine [37,38]. The chemical structure of local anesthetics in clinical use consists of an aromatic (lipophilic) benzene ring linked to an amino group (hydrophflic) via either an ester or an amide intermediate chain. The intermediate link classifies the local anesthetic as either an ester (procaine, chloroprocaine, tetracaine, and cocaine) or an amide (lidocaine, prilocaine, mepivacaine, bupi-vacaine, etidocaine, and ropivacaine). 

Local anesthetics are used to locally anesthetize a wide range of specific body parts or areas to allow painless surgery. Local anesthetics are most commonly used for dental procedures and repair of lacerations. They can also be used to provide neural blockade for larger, more painful procedures. Sites of LA application include localized injection, peripheral nerve blocks as well as central nerve blockade. The only safe agents which can be utilized for intravenous regional anesthesia (Bier block) are lidocaine and prilocaine. Other typical indications are outlined in Table 64.1. 

EMLA is a eutectic mbcture of 2.5% lidocaine and 2.5% prilocaine, which, when mbced, form a liquid that is formulated into a water-oil emulsion. EMLA is available as a cream, a gel and an anesthetic disc. Only the cream and gel are available in the USA. The cream is approved for use on intact skin for local anesthesia or genital mucosa for superficial minor surgery and as pretreatment for infiltration anesthesia. The gel is approved for adults who require localized anesthesia in periodontal pockets during scaling and/or root planning [1]. 

A 52-year-old woman developed spinal myoclonus 60 minutes after receiving 60 mg of hyperbaric prilocaine 5%. She had involuntary, asymmetrical, brief movements of the legs at a frequency of 10-20/minute. Treatment with intravenous diazepam 5 mg blunted the symptoms but did not abolish them they resolved completely 60 minutes after full recovery from spinal anesthesia. There were no residual signs of neurological impairment. 

In a review of the literature on adverse events associated with intravenous regional anesthesia the author concluded that Bier s block is safe when anesthetic doses are kept low [46 ]. Seizures have been reported at doses as low as 1.4 mg/kg of hdocaine, 4 mg/kg of prilocaine, and 1.6 mg/kg of bupivacaine. Serious cardiac events have only been reported with hdocaine and bupivacaine. 

Immiinologic Tumescent local anesthesia is widely used for liposuction as well as phlebectomy procedures and can cause severe adverse effects including fatal complications [TS ]. An allergic reaction to prilocaine has been reported. 

A 60-year-old women underwent intravenous regional anesthesia with 3 mg/kg of prilocaine 0.5% diluted with saline to a total of 40 ml for surgical treatment of carpal tunnel syndrome and 3 minutes after injection developed severe erythema and edema in the limb below the tourniquet. Intravenous hydrocortisone was started and the tourniquet was released after 20 minutes. All the skin signs disappeared within 1 hour and there were no systemic reactions after release of the tourniquet. A skin prick test later confirmed allergy to prilocaine. 

Gaigl Z, Seitz CS, Trautmaim A. Methemoglobinemia due to local anesthesia with low-dose prilocaine. Dermatol Surg 2009 Jan 35(1) 168-9. 

Dogramaci Y, Dogramaci AC, Esen E, Korkmaz T. Severe allergic reactions to prilocaine during intravenous regional anesthesia. Eur J Dermatol 2008 18(4) 462-3. 

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