You should not use labetalol if you have asthma, very low blood pressure, or a serious heart condition such as 2nd or 3rd degree "AV block," uncontrolled heart failure, or very slow heartbeats.
Before taking this medicine
You should not use labetalol if you are allergic to it, or if you have:
asthma;
"AV block" (2nd or 3rd degree);
uncontrolled heart failure;
very low blood pressure;
slow heartbeats that have caused you to faint; or
if your heart cannot pump blood properly.
Tell your doctor if you have ever had:
congestive heart failure;
angina (chest pain);
liver disease;
emphysema, chronic bronchitis, or other breathing problems;
pheochromocytoma (tumor of the adrenal gland);
diabetes;
coronary artery bypass surgery (sometimes called "CABG");
kidney disease; or
allergies.
Labetalol can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you use  labetalol.
It is not known whether labetalol will harm an unborn baby. Labetalol may cause low blood pressure, low blood sugar, slow heartbeats, or breathing problems in a newborn if the mother uses labetalol during pregnancy. Tell your doctor if you are pregnant or plan to become pregnant.
It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.
Labetalol is not approved for use by anyone younger than 18 years old.
