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Updated 2 Feb 2023 | Peripheral vascular disease


Modified release tablets containing 400mg pentoxifylline.

Drugs List

  • pentoxifylline 400mg modified release tablet
  • TRENTAL 400 modified release tablet
  • Dosage


    The initial dose is 400mg three times a day, however 400mg twice daily may be sufficient for some patients, especially in maintenance therapy.


    No dosage adjustment is recommended.


    Contraindicated in children under 18 years.

    Patients with Renal Impairment

    Creatinine clearance below 30ml/minute:
    A dose reduction by 30-50% may be necessary (guided by individual tolerance).

    Patients with Hepatic Impairment

    Consider dose reduction in severe hepatic impairment.


    Cerebral haemorrhage
    Extensive retinal haemorrhage
    Acute myocardial infarction
    Serious cardiac arrhythmias
    Porphyria - see Use in Porphyria section
    Children under 18 years
    Pregnancy - see Pregnancy section

    Precautions and Warnings

    Use with caution in patients with hypotension or severe coronary artery disease. A transient hypotensive effect is possible which might rarely result in reduced coronary artery perfusion.

    Renal Impairment - creatinine clearance less than 30ml/minute - see Dosage; Patients with Renal Impairment.

    Severe hepatic impairment - see Dosage; Patients with Hepatic Impairment.

    Pentoxifylline should be used with caution in patients receiving pharmacological treatment for diabetes mellitus and patients should be carefully monitored.

    Pentoxifylline has been reported to cause flushing, occasional tachycardia and rarely angina pectoris and hypotension, particularly at high doses. If these symptoms occur discontinuation of pentoxifylline or a reduction of the daily dosage is required. Discontinue immediately if an anaphylactic reaction occurs.

    Breastfeeding - see Lactation section.

    Use in Porphyria

    Pentoxifylline should not be used by patients with acute porphyria.

    Pregnancy and Lactation


    Pentoxifylline is contraindicated during pregnancy. Animal reproduction studies on rats and rabbits revealed no evidence of teratogenicity, however there was an increased incidence of embryo resorption in rats. At the time of writing there is limited experience of pentoxifylline use in human pregnancy. One surveillance study was suggestive of possible associations with birth defects but the small number of exposures may have been affected by other factors such as mother's disease, concurrent medication etc. At the time of writing, there is insufficient data to establish the safety of pentoxifylline in pregnancy. Schaefer notes that the pharmacology of the methylxanthines (of which pentoxifylline is a member) argues against noteworthy teratogenic potential and that if essential it might be employed, that exposure is not an indication for termination of pregnancy and that in cases of doubt a detailed ultrasound may be performed (Schaefer 2007).

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Licensed in pregnancy? - No, contraindicated.

    Recommended for use in pregnancy? - No

    Animal data - Reproduction studies on rats and rabbits reported no teratogenicity, however, there was an increased risk of resorption in rats.


    Pentoxifylline should be used with caution while breastfeeding. There is no information concerning the effects of pentoxifylline on breastfed infants. One pharmacokinetic study showed that pentoxifylline is excreted into human breast milk. One author concludes that the quantity excreted would not be expected to cause any adverse effects in breastfed infants, especially those over 2 months (LactMed 2007).

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Drug excreted in breast milk? - Yes, in small quantities.

    Considered suitable or recommended by manufacturer? - No.

    Drug substance licensed in infants? - No.

    Effects on Ability to Drive and Operate Machinery

    Pentoxifylline may cause dizziness, patients should not drive or operate machinery if affected.


    Pentoxifylline may cause dizziness, advise patients not to drive or operate machinery if they are affected.

    Side Effects

    Hypersensitivity reactions
    Sleep disturbances
    Intrahepatic cholestasis
    Anaphylactoid reaction
    Angioneurotic oedema
    Increase of liver transaminases
    Skin and mucosal bleeding
    Gastrointestinal bleeding
    Genitourinary bleeding
    Bleeding (surgical site)
    Angina pectoris
    Aseptic meningitis
    Gastrointestinal disturbances
    Epigastric discomfort
    Abdominal distention


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Shelf Life and Storage

    Do not store above 25 degrees C
    Store in original packaging

    Reference Sources

    British National Formulary, 61st Edition (2011) Pharmaceutical Press, London.

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 8th edition (2008) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Medications and Mothers' Milk, 14th Edition (2010) Hale, T. Hale Publishing, Amarillo, Texas.

    Summary of Product Characteristics: Trental 400. Sanofi-Aventis. Revised June 2011

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Pentoxifylline Last revised: December 27, 2007
    Last accessed: August 3, 2011.

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