There have been rare reports of severe hepatocellular injury with Labetalol therapy. The hepatic injury is usually reversible and has occured after both short and long term treatment. Appropriate laboratory testing should be done at the first sign or symptom of liver dysfunction.
If there is laboratory evidence of liver injury or the patient is jaundiced, Labetalol therapy should be stopped and not restarted.
Labetalol hydrochloride injection should be used with caution in patients with peripheral vascular disease as their symptoms may be exacerbated.
If the patient develops symptomatic bradycardia, then the dosage of Labetalol hydrochloride injection should be reduced.
Given the negative effect of beta-adrenoceptor blocking drugs on atrioventricular conduction time, Labetalol hydrochloride injection should be administered with caution to patients with first-degree atrio-ventricular block.
Special care should be taken with patients who suffer from heart failure or poor left ventricular systolic function. Heart failure should be controlled with appropriate therapy before use of Labetalol.
Labetalol hydrochloride injection need not be discontinued prior to anaesthesia but patients should receive intravenous Atropine prior to induction.
In patients with pheochromocytoma, Labetalol may be administered only after adequate alpha-blockade is achieved.
During anaesthesia Labetalol hydrochloride injection may mask the compensatory physiological responses of sudden haemorrhage (tachycardia and vasoconstriction).
Close attention must therefore be paid to blood loss and the blood volume maintained.
Particular care should be taken when Labetalol is used in patients with hepatic impairment as these patients metabolise Labetalol more slowly than patients without hepatic impairment.
As with other beta-adrenoceptor blocking drugs, Labetalol hydrochloride injection may mask the symptoms of hypoglycemia in diabetic patients and thyrotoxicosis.
Risk of anaphylactic reaction: While taking β-blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.
If patients receiving Labetalol require Adrenaline treatment, a reduced dosage of adrenaline should be used as concomitant administration of Labetalol with Adrenaline may result in bradycardia and hypertension.
There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenoceptor blocking drugs. The reported incidence is small and in most cases the symptoms have cleared when the treatment was withdrawn. Gradual discontinuance of the drug should be considered if any such reaction is not otherwise explicable.
The occurrence of intraoperative Floppy Iris Syndrome (IFIS, a variation of Small Pupil Syndrome) has been observed during cataract surgery in some patients on , or previously treated with, Tamsulosin. Isolated reports have also been received with other alpha-1 blockers and the possibility of a class effect cannot be excluded. As IFIS may lead to increased procedural complications during the cataract operation, current or past use of alpha-1 blockers should be made known to the ophthalmic surgeon in advance of surgery.
Effects on Ability to Drive and Use Machines: The use of Labetalol hydrochloride tablets is unlikely to result in any impairment of the ability of patients to drive or operate machinery. However, it should be taken into account that occasionally dizziness or fatigue may occur.
This is considered not relevant for Labetalol hydrochloride injection, as the injection is intended for i.v. use in hospitalised patients only.