Hypotension lidocaine

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,... 

Beta-blockers interact with a large number of other medications. The combination of beta-blockers with calcium antagonists should be avoided, given the risk for hypotension and cardiac arrhythmias. Cimetidine, hydralazine, and alcohol all increase blood levels of beta-blockers, whereas rifampicin decreases their concentrations. Beta-blockers may increase blood levels of phenothiazines and other neuroleptics, clonidine, phen-ytoin, anesthetics, lidocaine, epinephrine, monoamine oxidase inhibitors and other antidepressants, benzodiazepines, and thyroxine. Beta-blockers decrease the effects of insulin and oral hypoglycemic agents. Smoking, oral contraceptives, carbamazepine, and nonsteroidal anti-inflammatory analgesics decrease the effects of beta-blockers (Coffey, 1990). 

Lidocaine is one of the least cardiotoxic of the currently used sodium channel blockers. Proarrhythmic effects, including sinoatrial node arrest, worsening of impaired conduction, and ventricular arrhythmias, are uncommon with lidocaine use. In large doses, especially in patients with preexisting heart failure, lidocaine may cause hypotension—partly by depressing myocardial contractility. 

Cardiac failure may also affect metabolism by altering hepatic blood flow. However, even after heart attack without hypotension or cardiac failure, metabolism may be affected. For example, the plasma clearance of lidocaine is reduced in this situation. Other diseases such as those, which affect hormone levels hyper-or hypothyroidism, lack of or excess growth hormone, and diabetes can alter the metabolism of foreign compounds. 

Intravenous lidocaine has been used to treat severe chronic daily headache in 19 patients (three men, median age 37 years) (9). There were adverse effects during four infusions of lidocaine hyperkalemia (6.4 mmol/1), which did not resolve after withdrawal of lidocaine transient hypotension (75/50 mmHg), which was attributed to concomitant droperidol an unspecified abnormality of cardiac rhythm and on another occasion a transient bradycardia and chest pain with a normal electrocardiogram, fever, and intractable nausea. The study was neither randomized nor placebo-controlled, and in no case was the adverse event strongly associated with the administration of lidocaine. 

Lidocaine can cause dysrhythmias and hypotension. The dysrhythmias that have been reported include sinus bradycardia, supraventricular tachycardia (11), and rarely torsade de pointes (12). There have also been rare reports of cardiac arrest (2) and worsening heart failure (13). Lidocaine can also cause an increased risk of asystole after repeated attempts at defibrillation (14). Lidocaine may increase mortality after acute myocardial infarction, and it should be used only in patients with specific so-called warning dysrhythmias (that is frequent or multifocal ventricular extra beats, or salvos) (15). 

In New York City, five of 50 000 deaths over a 5-year period were associated with tumescent liposuction all had received hdocaine in doses of 10-40 mg/kg in association with general anesthesia and/or intravenous sedation and analgesia (49). Three patients died as a result of severe acute intraoperative hypotension and bradycardia with no identified cause, one died of fluid overload, and another died of pulmonary embolism. The authors speculated that hdocaine toxicity or lidocaine-related drug interactions could have contributed to some of the deaths, but other causes could not be ruled out. 

Enlund M, Mentell O, Krekmanov L. Unintentional hypotension from lidocaine infiltration during orthognathic surgery and general anaesthesia. Acta Anaesthesiol Scand 2001 45(3) 294-7. 

A watershed cerebral infarct with subsequent full recovery occurred in a 70-year-old man 8 hours after a hypotensive event following an incremental bolus of 1% lidocaine 10 ml via an established epidural catheter (131). 

An isobaric solution of sameridine given intrathecally in doses of 15, 20, and 23 mg has been compared with hyperbaric lidocaine 100 mg in 100 volunteers (178). Sameridine has both local anesthetic and opioid analgesic properties. There was one incident of transient paresthesia with sameridine 20 mg and two cases of bradycardia with lidocaine the incidence of hypotension was more frequent with lidocaine, but pruritus was more common with sameridine. 

The cauda has a tenuous blood supply, and in this patient with pre-existing vascular disease, perioperative hypotension and the use of intrathecal adrenaline may have precipitated ischemia in an area with very poor reserve. To follow this with an accidental large dose of lidocaine, which is neurotoxic in animals when directly applied and theorized to cause interruption of nerve blood supply, would add insult to injury. The authors questioned the wisdom of performing continuous epidural anesthesia in such patients, when frequent neurological assessments cannot be performed. 

A 21-year-old developed seizures, respiratory distress requiring tracheal intubation, severe hypotension, and then bradycardia culminating in asystole and death while gargling with 4% lidocaine 20 ml (800 mg) (341). 

Side effects should be monitored after the initiation of lidocaine. The most common adverse reactions are drowsiness, dizziness, paresthesia, and euphoria. Patients also may experience serious central nervous system (CNS) side effects such as confusion, agitation, psychosis, seizures, and coma, but usually only at supratherapeutic levels. The active metabolites of lidocaine are responsible for most of the CNS toxicities. Cardiovascular side effects, including atrioventricular block, hypotension, and circulatory collapse, are not as well correlated to lidocaine levels. 

Procainamide does not produce serious side-effects like quinidine and lidocaine (lignocaine) however, it is a negative inotrope and may cause hypotension QRS prolongation and ventricular arrhythmias can occur at high doses (Muir Mcguirk 1987). 

Penbutolol has been shown to increase the volume of distribution of lidocaine in normal patients, implying that it may increase the loading dose requirements in some patients. Clinical signs of overdose may include bradycardia, bronchospasm, heart failure, and severe hypotension. 

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