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Pentoxifylline

Pentoxifylline is used to peripheral vascular disease (poor blood flow to arms and legs), intermittent claudication (cramping muscle pain or numbness in the legs), and venous leg ulcers. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.
  • Article last reviewed 13 November 2025
  • 6 mins read

What is this medication for?

Pentoxifylline is a medication that increases blood flow to the arms and legs. It can be used to treat: 

  • Peripheral vascular disease (poor blood flow to arms and legs)
  • Intermittent claudication (cramping muscle pain or numbness in the legs)
  • Venous leg ulcers 

This medication may also be used for other conditions as determined by your doctor.

How should I take or use this medication?

Take this medication with or after food. Swallow the tablets whole with a glass of water. 

It may take several weeks to see the full effects of this medication. Do not stop taking your medication without consulting your doctor.

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

Take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose. Do not double the next dose to make up for the missed dose. 

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

Inform your doctor if:

  • You are allergic to this medication; caffeine-containing products (coffee, tea, colas); theobromine, theophylline, or if you have any other allergies.
  • You have had a recent bleeding problem in your brain or eye.
  • You have low blood pressure.
  • You have heart problems or recently have had a heart attack.
  • You have uneven and very fast heartbeats.
  • You previously or currently have gastric ulcer or duodenal ulcer.
  • You have kidney or liver problems.
  • You are taking any blood thinning medications, such as aspirin, rivaroxaban, warfarin; other medications; or supplements.
  • You have any health problems.
  • You are pregnant, planning to get pregnant, or are breastfeeding.
  • You are going for surgery including dental surgery. Inform your doctor/dentist that you are taking pentoxifylline.

What are some common side effects of this medication? ​

Certain side effects of this medication are not unusual and may even disappear during treatment. If any of the following effects persist or are severe, consult your doctor: 

  • Nausea, vomiting
  • Bloating
  • Dizziness
  • Headache
  • Flushing 

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

Consult your doctor as soon as possible if any of these additional effects occur, as they may indicate more serious side effects:

  • Allergic reaction (difficulty breathing; swelling of your lips, tongue, eyes or face; or itchy rashes over your whole body)
  • Chest pain
  • Irregular or fast heart beat
  • Severe dizziness or fainting

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

Inform your healthcare professional if you are taking or intend to take any other medications, supplements, traditional medications or herbal remedies.

How should I store this medication?

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

If the brand of Pentoxifylline that you received is Trenlin, it is recommended to store in a cool, dry place, below 25°C. If you are unable to store it under 25°C, please store the medicine in the refrigerator (2 to 8°C).

How do I throw away this medication safely? ​

Pack this medication into a black trash bag and seal it tightly before throwing 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 (NHG Health, 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.