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warnings
WARNINGS Hepatic Injury Severe hepatocellular injury, confirmed by rechallenge in at least one case, occurs rarely with labetalol therapy. The hepatic injury is usually reversible, but hepatic necrosis and death have been reported. Injury has occurred after both short- and long-term treatment and may be slowly progressive despite minimal symptomatology. Similar hepatic events have been reported with a related compound, dilevalol HCl, including two deaths. Dilevalol HCl is one of the four isomers of labetalol. Thus, for patients taking labetalol, periodic determination of suitable hepatic laboratory tests would be appropriate. Laboratory testing should also be done at the very first symptom or sign of liver dysfunction (e.g., pruritus, dark urine, persistent anorexia, jaundice, right upper quadrant tenderness, or unexplained "flu-like" symptoms). If the patient has jaundice or laboratory evidence of liver injury, labetalol should be stopped and not restarted. Cardiac Failure Sympathetic stimulation is a vital component supporting circulatory function in congestive heart failure. Beta-blockade carries a potential hazard of further depressing myocardial contractility and precipitating more severe failure. Although beta-blockers should be avoided in overt congestive heart failure, if necessary, labetalol can be used with caution in patients with a history of heart failure, who are well compensated. Congestive heart failure has been observed in patients receiving labetalol. Labetalol does not abolish the inotropic action of digitalis on heart muscle. In Patients without a History of Cardiac Failure In patients with latent cardiac insufficiency, continued depression of the myocardium with beta-blocking agents over a period of time can lead, in some cases, to cardiac failure. At the first sign or symptom of impending cardiac failure, patients should be fully digitalized and/or be given a diuretic, and the response observed closely. If cardiac failure continues, despite adequate digitalization and diuretic, labetalol therapy should be withdrawn (gradually if possible). Ischemic Heart Disease Angina pectoris has not been reported upon labetalol discontinuation. However, following abrupt cessation of therapy with some beta-blocking agents in patients with coronary artery disease, exacerbations of angina pectoris and, in some cases, myocardial infarction have been r...
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adverse reactions
ADVERSE REACTIONS Labetalol hydrochloride injection is usually well tolerated. Most adverse effects have been mild and transient and in controlled trials involving 92 patients did not require labetalol withdrawal. Symptomatic postural hypotension (incidence 58%) is likely to occur if patients are tilted or allowed to assume the upright position within 3 hours of receiving Labetalol hydrochloride injection. Moderate hypotension occurred in 1 of 100 patients while supine. Increased sweating was noted in 4 of 100 patients, and flushing occurred in 1 of 100 patients. The following also were reported with labetalol hydrochloride injection with the incidence per 100 patients as noted: Cardiovascular System: Ventricular arrhythmia in 1. Central and Peripheral Nervous Systems: Dizziness in 9; tingling of the scalp/skin 7; hypoesthesia (numbness) and vertigo, 1 each. Gastrointestinal System: Nausea in 13; vomiting 4; dyspepsia and taste distortion, 1 each. Metabolic Disorders: Transient increases in blood urea nitrogen and serum creatinine levels occurred in 8 of 100 patients; these were associated with drops in blood pressure, generally in patients with prior renal insufficiency. Psychiatric Disorders: Somnolence/yawning in 3. Respiratory System: Wheezing in 1. Skin: Pruritus in 1. The incidence of adverse reactions depends upon the dose of labetalol. The largest experience is with oral labetalol. Certain of the side effects increased with increasing oral dose as shown in the table below which depicts the entire U.S. therapeutic trials data base for adverse reactions that are clearly or possibly dose related. Labetalol Daily Dose (mg) 200 300 400 600 800 900 1200 1600 2400 Number of Patients 522 181 606 608 503 117 411 242 175 Dizziness (%) 2 3 3 3 5 1 9 13 16 Fatigue 2 1 4 4 5 3 7 6 10 Nausea