Labetalol

What is labetalol?

Labetalol is used to treat high blood pressure (hypertension). In particular, labetalol is one of the preferred medicines to treat high blood pressure in pregnancy. It belongs to a group of medicines called beta-blockers. Beta-blockers work by blocking some natural chemicals in the body, to lower blood pressure. Labetalol is available as tablets or injection. 

Dose

• The usual dose of labetalol tablets is 100 mg to 200 milligrams two times a day.
• Your doctor will start you on a lower dose and increase your dose if needed. 
• Always take your labetalol exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much labetalol to take, how often to take it and any special instructions.

How to take labetalol

• Swallow your labetalol tablets with a glass of water.
• Take your labetalol doses at the same times each day.
• Labetalol is best taken with food.
• If you drink alcohol, ask your doctor for advice about taking labetalol and alcohol. Alcohol may increase your chance of side effects such as dizziness, by adding to the blood pressure lowering effect of labetalol.
• If you have diabetes, labetalol can block the symptoms of low blood sugar. Speak to your doctor about advice for this.
• If you forget your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
• Do not stop taking labetalol suddenly; speak to your doctor or nurse before stopping.

Precautions – before taking labetalol

• Do you have asthma?
• Do you have diabetes?
• Do you have problems with your kidneys?
• Do you play a professional sport?
• Are you pregnant or breastfeeding?
• Have you ever had an allergic reaction to a medicine?
• Are you are taking or using any other medicines? This includes any medicines you are using which are available to buy from a pharmacy, supermarket or natural health store without a prescription.

If so, it’s important that you tell your doctor or pharmacist before you start taking labetalol. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Possible side effects

Like all medicines, labetalol can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Diabetes

If you have diabetes you need to take extra care to measure your blood glucose levels regularly.

• Beta-blockers can cause an increase in blood glucose levels, especially when you first start taking them. This effect usually settles with time.
• Beta-blockers may reduce the warning signs of a low blood sugar level (hypoglycaemia – often called a hypo). For example, you may not have the feeling of fast, irregular or strong heartbeats (palpitations) or tremor, which can occur when your blood glucose is going too low. If you are worried about this, talk to your doctor. Do not stop taking your beta-blocker without checking with your doctor first. Read more about hypoglycaemia.

Asthma

If you have asthma, taking a beta blocker may trigger your asthma symptoms or make them worse. Not everybody with asthma is sensitive to these medicines. If you are worried about this, talk to your doctor. They may be able to prescribe a different medicine or increase the dose of your asthma preventer medication. Do not suddenly stop taking your beta-blocker without talking to your doctor first. This can be dangerous and make you feel unwell. Read more about medicines that may trigger asthma symptoms.

Other side effects

Interactions

• Check with a pharmacist before taking over the counter medicines such as:
  • Cold or flu tablets containing phenylephrine (e.g. Sudafed PE), or diphenhydramine (e.g. Benadryl Original)
  • Anti-inflammatories such as diclofenac (e.g. Voltaren Rapid), ibuprofen (e.g. Nurofen), mefenamic acid (e.g. Ponstan), naproxen (e.g. Naprogesic)
• Labetalol may interact with other medications and herbal supplements, so check with your doctor or pharmacist before starting labetalol or before starting any new medicines.

Learn more

labetalol New Zealand Formulary Patient Information

References

1. Labetalol New Zealand Formulary