What You Should Know About Labetalol Side Effects

Labetalol is a well-established blood pressure medication that's been used safely for decades. But like all medications, it can cause side effects — some mild, some serious. Knowing what to watch for helps you stay safe and makes it easier to have informed conversations with your doctor.

This guide covers the most common Labetalol side effects based on FDA labeling, the serious ones that need immediate attention, and practical tips for managing them.

What Is Labetalol?

Labetalol is a combined alpha-beta blocker that lowers blood pressure by relaxing blood vessels and slowing your heart rate. It's available as a generic in 100 mg, 200 mg, and 300 mg tablets and as an IV injection for hospital use. It was originally sold under the brand names Trandate and Normodyne.

For a deeper dive into how it works, see our guide on Labetalol's mechanism of action. For full prescribing details, check out What Is Labetalol?

Common Side Effects

These side effects are the most frequently reported in clinical trials. Most are mild and often improve as your body adjusts to the medication over the first few weeks:

• Dizziness — Reported by about 11% of patients. This is the most common side effect and is related to the blood-pressure-lowering action of the drug.
• Nausea — Affects roughly 6% of people taking Labetalol.
• Fatigue — About 5% of patients report feeling more tired than usual.
• Nasal congestion — Occurs in about 3% of patients due to the alpha-blocking effect relaxing blood vessels in the nasal passages.
• Indigestion (dyspepsia) — Around 3% of patients experience stomach discomfort.
• Headache — Reported by about 2% of patients.
• Tingling of the scalp or skin — A unique side effect of Labetalol that usually happens early in treatment and goes away on its own.
• Vertigo — About 2% of patients experience a spinning sensation.
• Ejaculation failure — Reported by about 2% of male patients.
• Orthostatic hypotension — A drop in blood pressure when standing up, reported in about 1% of patients taking oral Labetalol (but up to 58% with the IV form in hospitals).

Serious Side Effects

These are less common but require immediate medical attention. Call your doctor right away or go to the emergency room if you experience:

• Signs of liver damage (hepatotoxicity) — Yellowing of the skin or eyes (jaundice), dark urine, severe stomach pain, unusual fatigue, or loss of appetite. Labetalol has been associated with rare but serious liver injury.
• Severe drop in blood pressure — Feeling faint, lightheaded, or passing out, especially when standing up.
• Signs of heart failure — Sudden weight gain, swelling of the ankles or feet, shortness of breath (especially when lying down), extreme tiredness.
• Bronchospasm — Wheezing, difficulty breathing, tightness in the chest. This is more likely in people with asthma or other lung conditions.
• Slow heartbeat (severe bradycardia) — Heart rate below 50 beats per minute with symptoms like dizziness, confusion, or fainting.
• Allergic reaction — Rash, hives, swelling of the face, lips, tongue, or throat, difficulty breathing.

Side Effects in Specific Populations

Pregnant Women

Labetalol is one of the most commonly prescribed blood pressure medications during pregnancy, particularly for pregnancy-induced hypertension and pre-eclampsia. While generally considered safer than many other blood pressure drugs in pregnancy, it should still be used only when the benefit outweighs the risk. Your OB/GYN will monitor you closely.

Older Adults

Elderly patients may experience more pronounced dizziness and orthostatic hypotension. Doctors often start with lower doses and increase gradually.

People With Diabetes

Labetalol can mask the symptoms of low blood sugar (hypoglycemia), such as a rapid heartbeat and trembling. If you have diabetes, monitor your blood sugar more carefully and discuss this risk with your doctor. See our drug interactions guide for more details.

People With Asthma or COPD

Labetalol is generally contraindicated in people with obstructive airway diseases like asthma. The beta-blocking effect can trigger bronchospasm. If you have asthma, your doctor will likely choose a different medication.

How to Manage Common Side Effects

Here are practical tips for dealing with the most common Labetalol side effects:

• Dizziness: Stand up slowly from sitting or lying positions. Avoid driving or operating heavy machinery until you know how Labetalol affects you.
• Nausea: Take Labetalol with food. Eating a small snack before your dose can help settle your stomach.
• Fatigue: Give it time — fatigue often improves after 1 to 2 weeks. If it persists, talk to your doctor about adjusting the dose or timing.
• Nasal congestion: A saline nasal spray can help. Avoid decongestants containing Pseudoephedrine, as they can raise blood pressure.
• Orthostatic hypotension: Stay hydrated, and take your time when changing positions. Dangling your legs at the edge of the bed before standing can help.

Important: Never Stop Labetalol Suddenly

Abruptly stopping Labetalol can cause rebound effects, including a dangerous spike in blood pressure, chest pain (angina), or even heart attack. If you need to stop taking it, your doctor will gradually reduce your dose over 1 to 2 weeks.

Final Thoughts

Most people tolerate Labetalol well. The common side effects — dizziness, nausea, fatigue — are usually mild and temporary. But knowing the warning signs of serious problems like liver damage, bronchospasm, or heart failure is important.

If you're experiencing side effects that bother you, don't stop taking Labetalol on your own. Talk to your doctor first — there may be a dose adjustment or alternative medication that works better for you.

Need help finding Labetalol at a pharmacy near you? Search Medfinder for real-time availability.