[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Haemorheologic agents](https://durgical.com/en/pharmacology/classes/haemorheologic-agents/) › Pentoxifylline

# Pentoxifylline

## Haemorheologic agents?

Haemorheologic agents

A methylxanthine that makes blood flow more easily (less viscous, more flexible red cells). Used for intermittent claudication; modest benefit.

Updated Nov 12, 2026

Also called: oxpentifylline

## Quick facts

**Group**
[Haemorheologic agents](https://durgical.com/en/pharmacology/classes/haemorheologic-agents/)

**Target**
Phosphodiesterases (non-selective; PDE4A shown)

**Used for**
Sometimes used for venous leg ulcers

**Key effects**
Nausea · Dizziness

**Monitor**
Signs of bleeding · INR when given with warfarin

**ATC**
C04AD03

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

✂**Phosphodiesterases (non-selective; PDE4A shown)**Pentoxifylline

ⓘ The figure shows pentoxifylline in the active site of human phosphodiesterase 4A, one of the phosphodiesterases it inhibits.

**Target in 3D:** Phosphodiesterases (non-selective; PDE4A shown). PDB structure 3TVX (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/3TVX) · Drag to rotate · pinch to zoom

Pentoxifylline is a xanthine derivative (related to caffeine and theophylline) that inhibits phosphodiesterases and raises cAMP in blood cells. Red cells become more flexible, blood viscosity falls, white cells are less able to stick and activate. Blood flows more easily through narrowed small vessels in the limbs, which can lengthen walking distance in claudication.

- Inhibits phosphodiesterases: cAMP rises in blood cells
- Red cells more flexible; blood less viscous
- White cells adhere and activate less
- Better microcirculatory flow in ischaemic limbs

## Indications

- Intermittent claudication from chronic occlusive arterial disease of the limbs [Peripheral artery disease →](https://durgical.com/en/conditions/peripheral-artery-disease/)
- Sometimes used for venous leg ulcers [Venous leg ulcer →](https://durgical.com/en/conditions/venous-leg-ulcer/)

## Adverse effects

### Common

- Nausea, vomiting, upset stomach, wind
- Dizziness, headache

### Serious (rare, important)

- Bleeding, especially with anticoagulants or antiplatelets
- Chest pain (angina), palpitations and arrhythmia
- Hypotension; anaphylactic reactions (rare)

## Contraindications

- Recent bleeding in the brain or retina
- Intolerance to pentoxifylline or other methylxanthines (caffeine, theophylline, theobromine)

## Key interactions

**Warfarin and other vitamin K antagonists**
Prothrombin time may rise; INR is checked more often.

**Theophylline**
Higher theophylline levels and toxicity.

**Strong CYP1A2 inhibitors (ciprofloxacin, fluvoxamine) and cimetidine**
Higher pentoxifylline levels.

**Antihypertensives**
Small additional fall in blood pressure.

## What is monitored

- Signs of bleeding; blood counts when bleeding risk is high
- INR when given with warfarin
- Blood pressure, especially with other cardiovascular drugs
- Walking distance and symptoms

## Administration and safety

- Extended-release tablet with meals, swallowed whole, not broken, crushed or chewed.
- Benefit may take weeks; it supports, not replaces, exercise, smoking cessation or revascularisation.
- Surgeons and dentists are told that the patient takes it.

## Pregnancy and breastfeeding

There are no adequate human studies; it is used only if the benefit justifies the possible risk to the fetus.

## Nursing care

- Before: ask about recent bleeding (brain, eye, stomach) and caffeine or theophylline intolerance.
- During: teach to report bleeding, black stools, chest pain or palpitations.
- Check blood pressure; teach to take it with food to reduce nausea.
- Encourage supervised walking and smoking cessation.

## Pharmacokinetics

**Absorption**
Oral extended-release tablet, almost completely absorbed, with a first-pass effect.

**Metabolism**
Extensively metabolised to active metabolites; exposure rises markedly in liver impairment.

**Elimination**
Almost entirely in the urine; metabolites accumulate in kidney impairment.

**Onset and duration**
Benefit appears over weeks.

## Memory aid

PENTOXIFYLLINE makes blood 'PENT-up' no more: thinner, more flexible flow for claudicating legs.

## Test yourself

Think of the answer, then tap the question to see it.

## How does pentoxifylline improve blood flow?

It makes red cells more flexible and lowers blood viscosity (via phosphodiesterase inhibition).

## Which bleeding history rules it out?

Recent cerebral or retinal haemorrhage.

## Which drug's levels rise when given with pentoxifylline, since both are methylxanthines?

Theophylline.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/pentoxifylline/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Cilostazol](https://durgical.com/en/pharmacology/cilostazol/)
- [Theophylline](https://durgical.com/en/pharmacology/theophylline/)
- [Acetylsalicylic acid](https://durgical.com/en/pharmacology/acetylsalicylic-acid/)

## Related conditions 2

- [Peripheral artery disease](https://durgical.com/en/conditions/peripheral-artery-disease/)
- [Venous leg ulcer](https://durgical.com/en/conditions/venous-leg-ulcer/)

[← Back to the class: Haemorheologic agents](https://durgical.com/en/pharmacology/classes/haemorheologic-agents/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Pentoxifylline: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a685027.html) (MedlinePlus (U.S. National Library of Medicine), 2017); [PENTOXIFYLLINE tablet, extended release](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=40ae2d9a-0d95-640d-0640-f76e7e1a13cb) (DailyMed (U.S. National Library of Medicine), 2026); [The structure of PDE4A with pentoxifylline at 2.84A resolution](https://www.rcsb.org/structure/3TVX) (RCSB Protein Data Bank, 2012); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C04AD03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/pentoxifylline/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/pentoxifylline/