Lidocaine dosage

The lidocaine/propranolol interaction is established and of clinical importance. Monitor the effects of concurrent use and reduce the intravenous lidocaine dosage if necessary to avoid toxicity. The situation with other... 

Lidocaine may produce clinically significant hypotension, but this is exceedingly uncommon if the drug is given in moderate dosage. Depression of an already damaged myocardium may result from large doses. 

Although serious adverse reactions to lidocaine are uncommon, high dosage by any route may produce cardiovascular depression, bradycardia, hypotension, arrhythmias, heart block, cardiovascular collapse, and cardiac arrest,... 

Antiarrhythmic therapy carries with it a number of risks. In some cases, the risk of an adverse reaction is clearly related to high dosages or plasma concentrations. Examples include lidocaine-induced tremor or quinidine-induced cinchonism. In other cases, adverse reactions are unrelated to high plasma concentrations (eg, procainamide-induced agranulocytosis). For many serious adverse reactions to antiarrhythmic drugs, the combination of drug therapy and the underlying heart disease appears important. 

Pharmacokinetics Lidocaine is given intravenously because of extensive first-pass transformation by the liver, which precludes oral administration. The drug is dealkylated and eliminated almost entirely by the liver, consequently dosage adjustment may be necessary in patients with liver dysfunction. 

The authors pointed out that the dose of lidocaine used was well within recommended dosage hmits. However, they stressed that a more appropriate dosing schedule should be worked out for neonates. 

In patients with heart and liver disease, the dosage requirement of lidocaine is reduced the half-life of lidocaine is substantially longer in patients with liver disease (59). 

Tetracaine is a highly lipid-soluble, potent aminoester. It is primarily used as a constituent of many different topical formulations and for spinal anesthesia. It is four times as potent as lidocaine, and unless great caution is taken in dosage, serious systemic adverse effects can develop. 

Baggot J D 1992 Bioavailability and bioequivalence of veterinary drug dosage forms, with particular reference to horses an overview. Journal of Veterinary Pharmacology and Therapeutics 15 160-173 Dirikolu L, Lehner A F, Karpiesiuk W et al 2000 Identification of lidocaine and its metabolites in post-administration equine urine by ELISA and MS/MS. Journal of Veterinary Pharmacology and Therapeutics 23 215-222 Evans W E 1992 General principles of applied... 

In 1996, Nicole Wan, a student at the University of Rochester, underwent bronchoscopy as a healthy volunteer. She collapsed at home shortly afterwards and died at home two days later. The cause of death was an excessive dose of lidocaine administered to help the procedure. An investigation determined a failure to establish safe dosage guidelines for lidocaine administration during these procedures. 

Heart failure is often overlooked as a disease state that can alter drug disposition. Severe heart failure decreases cardiac output and therefore reduces hver blood flow. Theophylline, lidocaine, and drugs with high extraction ratios are compounds whose clearance declines with decreased liver blood flow. Initial dosages of these drugs should be reduced in patients with moderate to severe heart failure (New York Heart Association class III or IV) by 25% to 50% until steady-state concentrations and response can be determined. 

A choice of salts can also expand the formulation options for a material. The antimalarial agent a-(2-piperidyl)-3,6-bis(trifluoromethyl)-9-phenanthrene-methanol hydrochloride (Fig. 9) exhibited poor solubility, was delivered as an oral formulation, and required a single dosing of 750 mg (13). Seven salts and the free base were evaluated. The lactate salt was found to be 200 times as soluble as the hydrochloride salt (Table 3). This enhanced solubility would make it possible to reduce the oral dose to achieve the same therapeutic response as well as develop a parenteral formulation for the treatment of malaria. However, the case of lidocaine hydrochloride (Fig. 14) demonstrates that a compound limited to parenteral and topical formulations can be expanded to oral administration by changing to a salt form with acceptable physical properties (16). The hydrochloride salt was hygroscopic, difficult to prepare, and hard to handle. Six salts were evaluated for salt formation, solubility, and hygroscopicity. Other salts, such as phosphate, exhibited properties acceptable for dry pharmaceutical dosage forms. 

The shrinking of mucous membranes decreases operative bleeding while improving surgical visualization. Comparable vasoconstriction can be achieved with other local anesthetics by the addition of a low concentration of a vasoconstrictor such as phenylephrine (0.005%). Epinephrine, topically applied, does not prolong the duration of action of local anesthetics applied to mucous membranes because of poor penetration. Maximal safe total dosages for topical anesthesia in a healthy 70-kg adult are 300 mg for lidocaine, 150 mg for cocaine, and 50 mg for tetracaine. 

Amide-type local anesthetics (e.g., procainamide and lidocaine) also possess antiarrhythmic activity when given parenterally and at a subanesthetic dosage. Although this action can be attributed to their actions on sodium channels in cardiac tissues, current evidence suggests a distinctly different mechanism of action with respect to the modulation of channel receptors and the location of binding sites for these compounds (19,20). 

The dosage of propofol may need to be reduced after the use of bupivacaine or lidocaine (e.g. during regional anaesthetic techniques). Similarly, epidural lidocaine reduces sevoflurane requirements, and is likely to have the same effect on other inhalational anaesthetics. 

Direct information is very limited. It may be necessary to increase the dosage of lidocaine to achieve the desired therapeutic response in patients on phenobarbital or other barbiturates. 

Okamoto, H. Nakamori, T. Arakawa, Y. lida, K. Danjo, K. Development of polymer film dosage forms of lidocaine for buccal administration. II. Comparison of preparation methods. J. Pharm. Sci. 2002, 91 (11), 2424-2432. 

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