Local anesthetics indications

Unlike many categories of pharmaceutical agents, the group muscle relaxants has no reference to a common structure or mechanism of action. Whereas local anesthetics indicates a group of pharmaceutical agents with similar structure and mechanism of action, the approximately ten drugs of the muscle relaxants category have virtually no shared structure and no shared mechanism of action. 

Lidocaine hydrochloride [73-78-9] (Xylocaine), is the most versatile local anesthetic agent because of its moderate potency and duration of action, rapid onset, topical activity, and low toxicity. Its main indications are for infiltration, peripheral nerve blocks, extradural anesthesia, and in spinal anesthesia where a duration of 30 to 60 min is desirable. Because of its vasodilator activity, addition of the vasoconstrictor, epinephrine, increases the duration of action of Hdocaine markedly. It is also available in ointment or aerosol preparations for a variety of topical appHcations. 

Cocaine is another example of a dmg with a complex pharmacological profile responsible for different properties probably concurring due to QT prolongation. It has a local anesthetic action (and therefore shares the pharmacological properties mentioned above), but recent reports also indicate the blockade of hERG K+ currents [47-49]. Thus, it is not unexpected that cocaine has been associated with QT prolongation and occurrence of TdP [50-53]. 

The amine function means that local anesthetics exist either as the neutral amine or positively charged ammonium cation, depending upon their dissociation constant (pKa value) and the actual pH value. The pKa of typical local anesthetics Ues between 7.5 and 9.0. The pka indicates the pH value at which 50% of molecules carry a proton. In its protonated form, the molecule possesses both a polar hydrophilic moiety (protonated nitrogen) and an apolar lipophilic moiety (ring system)—it is amphiphilic. 

Ziconotide is a non-opioid, non-NSAID, non-local anesthetic used for the amelioration of chronic pain. In December 2004 the FDA approved ziconotide for intrathecal administration. The drug is derived from a marine snail toxin. Its mechanism of action has not yet been elucidated. Due to serious side effects or lack of efficacy when delivered through more conventional routes ziconotide must be administered in-trathecally. It s use is considered appropriate only for management of severe chronic pain in patients for whom intrathecal therapy is indicated. 

Patients taking MAOIs are advised to carry identification cards that indicate that they are taking MAOIs. Before accepting any medication or anesthetic, patients should notify their physicians that they are taking MAOIs. When patients undergo dental procedures, local anesthetics without vasoconstrictors (e.g., epinephrine) must be used. 

Clinically, local anesthetics may be used in a variety of pharmaceutical forms and administered in many ways, tailored to the desired clinical indication ... 

Pharmacological Profile. The profile of the ideal local anesthetic agent depends largely on the type and length of the surgical procedure for which it is applied. Procedures could include neuraxial (spinal and epidural) anesthesia, nerve and plexus blocks, or field blocks (local infiltration). In general, tine ideal agent should have a short onset of anesthesia and be useful for multiple indications such as infiltration, nerve blocks. 

The primary clinical uses of local anesthetics according to their method of administration and specific indications are presented here. 

Finally, local anesthetics can be administered via a transdermal patch.1 In particular, transdermal patches containing 5% lidocaine have been used to treat localized pain in musculoskeletal conditions (osteoarthritis, low back pain, myofascial pain)22,25,26 and various types of neuropathic pain (postherpetic neuralgia, diabetic neuropathy).2,24,58 As indicated in Chapter 2, transdermal patches provide a convenient and predictable method for administering drugs to a given anatomical site, and lidocaine patches are now being used to provide symptomatic relief in many conditions involving fairly localized pain. 

If an overdose of the local anesthetic has been taken by mouth, evacuation and chemical antidotes are indicated. If the anesthetic was injected, absorption should be blocked by ligation, if possible. Whatever delays death is likely to save the life in view of the rapid destruction of these drugs. If... 

Finally, it is worth mentioning a study in which chromatographic indices on IAMs were determined for 13 local anesthetics [22] (Table 5.2). Regression analysis result-... 

Anesthetic agents are a diverse class of chemicals which are extremely important in modern medicine. They are generally used to produce a loss of sensation to all stimuli, either in a specific anatomical area, or a total loss of consciousness. Anesthetics differ from analgesics in that analgesics such as aspirin, acetaminophen, ibuprofen, or morphine act to decrease pain, but not other sensations. Anesthetics can be broadly categorized into two general classes, local anesthetics and general anesthetics. These classes are independent as far as indication, chemical class, routes of administration, and toxicity, and thus will be considered separately. It will be noted when one compound within a class differs from the others. 

Tropacocaine is employed as a local anesthetic and closely resembles cocaine in its action. It is said to possess only one-half the toxicity of cocaine and to produce less dilation of the pupil of the eye. Anesthesia sets in more rapidly and is more prolonged than in the case of cocaine. In lumbar anesthesia tropacocaine is indicated as the most reliable and least dangerous of the drugs in use. 

This Eutectic Mixture of Local Anesthetics is used successfully in many brief but painful minor operations. EMLA has been tried as a local anesthetic for phenol peels. However, the following arguments should restrict its use in this indication ... 

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