Medication Information Leaflet

What is this medication for?

Methyldopa is used to control high blood pressure. It works by relaxing the blood vessels to allow blood to pass through more easily.

How should I take or use this medication?

• Do not stop taking your medication without checking with your healthcare professional.
• You may take this medication with or without food.

What should I do if I forget to take or use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take when taking or using this medication?

Inform your healthcare professional if:

• You are allergic to this medication or any of the other ingredients in this medication
• You are breastfeeding
• You have liver or kidney problems
• You have a condition called Pheochromocytoma (tumour of the adrenal gland) or Paraganglioma (tumour near the adrenal gland)
• You have a blood problem called Haemolytic anaemia or Porphyria
• You are taking any iron products by mouth
• You are taking any other medications, including supplements, traditional medications and herbal remedies.

What are some common side effects of this medication?

Most side effects from methyldopa should get better over time as your body adjusts to the medication. Inform your healthcare professional if these side effects do not go away or bother you. Such side effects include:

• Dizziness and light-headedness
  • This may occur especially when you change positions from a lying to sitting position or from a sitting to standing position.  You can prevent this by getting up slowly or changing positions slowly. Take a rest by sitting or lying down if you feel dizzy.
• Drowsiness
  • Be careful when driving or operating machinery as this medication may cause drowsiness and dizziness. Do not take alcohol or other medications that make you less alert.
• Headache and stuffy nose

Inform your doctor if you experience any of the following side effects: 

• Persistent swelling of ankles or feet, breathlessness or sudden unexplained weight gain
• Decreased sexual desire or ability 
• Breast swelling or tenderness 
• Changes in your mood
• Chest pain or slowed heart rate 

What are some rare but serious side-effects that I need to seek medical advice immediately?

Very rarely, methyldopa may cause blood or liver problems. Stop this medication and see a doctor immediately if you notice any of these symptoms:

• Liver injury - Dark brown urine, light coloured stools (pale grey/ clay coloured), nausea, vomiting, loss of appetite, yellowing of skin or eyes
• Low white blood cell counts – signs of infection like unexplained fever, chills or sore throat

The symptoms of a drug allergy include one or more of the following:

• Swollen face/eyes/lips/tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

Some medications may interact with methyldopa and affect its effectiveness or increase the risk of side effects. However, these medications may also be important for your treatment. Inform your healthcare professional of the other medications you are currently taking. Examples include:

• Specific medications known as monoamine oxidase inhibitors, which is used to treat: Parkinson’s disease (e.g. selegiline, rasagiline) or Depression (e.g. moclobemide)

You should take iron products at least two hours before or after methyldopa as taking them together might decrease the absorption of methyldopa into your body.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How do I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.

Disclaimer

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on February 2025