LidoSite Disease Interactions

Antiarrhythmic agents can induce severe hypotension (particularly with IV administration) or induce or worsen congestive heart failure (CHF). Patients with primary cardiomyopathy or inadequately compensated CHF are at increased risk. Antiarrhythmic agents should be administered cautiously and dosage and/or frequency of administration modified in patients with hypotension or adequately compensated CHF. Alternative therapy should be considered unless these conditions are secondary to cardiac arrhythmia.

Lidocaine is rapidly and extensively metabolized by the liver. Less than 10% is eliminated unchanged in the urine. Several inactive and two active forms (MEGX and GX) have been identified. MEGX and GX exhibit antiarrhythmic and convulsant properties. GX accumulates during prolonged intravenous lidocaine infusion. The pharmacokinetic disposition of lidocaine is altered by changes in hepatic function, including hepatic blood flow. Therapy with lidocaine should be administered cautiously and dosing modifications for repeated or loading and maintenance doses may be necessary. Clinical monitoring of cardiac (continuous ECG) is required and serum metabolite concentrations and monitoring hepatic function are recommended.

Lidocaine is primarily eliminated by the kidney. Less than 10% is eliminated unchanged in the urine. Two active metabolites (MEGX and GX) have been identified that exhibit antiarrhythmic and convulsant properties. GX accumulates during prolonged intravenous lidocaine infusion. Serum concentrations of lidocaine and the active metabolites are increased and the half-life prolonged in patients with renal impairment. Therapy with lidocaine should be administered cautiously and dosing modified for repeated or maintenance doses in patients with compromised renal function. Clinical monitoring of cardiac function (continual ECG) is required and serum metabolite concentrations and monitoring renal function are recommended.

Seizures have occurred during lidocaine therapy and have been associated with the rapid administration of a large intravenous doses or accumulation of active metabolites with maintenance therapy. Therapy with lidocaine should be administered cautiously to patients with or predisposed to seizure disorders. Clinical monitoring of cardiac (continuous ECG) is required, and serum metabolite concentrations are recommended.

The use of lidocaine is contraindicated in patients with Stokes-Adam syndrome, Wolff-Parkinson White syndrome, or second- or third-degree AV block in the absence of a functional artificial pacemaker, or congenital QT prolongation.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

The use of sympathomimetic amines has been infrequently associated with significant hypotension especially in dehydrated patients secondary to the drug's beta-2 mediated vasodilation. Hypovolemia should be corrected, if possible, before administering sympathomimetic amines. Blood pressure and ECG should be monitored at regular intervals. Monitoring of cardiac output and pulmonary wedge pressure may also be desired.

Electrolyte imbalance can alter the therapeutic effectiveness of antiarrhythmic agents. Hypokalemia and hypomagnesemia can reduce the effectiveness of antiarrhythmic agents. In some cases, these disorders can exaggerate the degree of QTc prolongation and increase the potential for torsade de pointes. Hyperkalemia can potentiate the toxic effects of antiarrhythmic agents. Electrolyte imbalance should be corrected prior to initiating antiarrhythmic therapy. Clinical monitoring of cardiac function and electrolyte concentrations is recommended.

Epinephrine should be administered with caution to patients with Parkinson's disease as these patients may experience psychomotor agitation or notice a temporary worsening of symptoms.

Acidosis, hypoxia, and hypercapnia may reduce the effectiveness of sympathomimetic amines in raising blood pressure. These conditions should be corrected before initiating therapy with sympathomimetic amines, if possible. Monitoring the patients acid-base balance, carbon dioxide levels, and oxygen saturation is recommended.

Sympathomimetic agents may cause increases in blood glucose concentrations. These effects are usually transient and slight but may be significant with dosages higher than those normally recommended. Therapy with sympathomimetic agents should be administered cautiously in patients with diabetes mellitus. Closer monitoring of blood glucose concentrations may be appropriate.