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Tramadol blood thinning: Does tramadol raise or lower blood pressure?

Does tramadol raise or lower blood pressure?

Medically reviewed by Sally Chao, MD. Last updated on Oct 24, 2022.

Tramadol is a synthetic opioid pain reliever that has been linked to both high blood pressure and low blood pressure. But, neither adverse reaction is common when the medicine is taken as directed.

  • Studies on tramadol have reported that between 1% and 5% of people taking the extended-release version and a very small number of people taking the fast-acting version developed high blood pressure (hypertension).
  • Less than 1% of people taking tramadol developed low blood pressure (hypotension) in studies.

Those who had low blood pressure in the studies sometimes had what’s called postural or orthostatic hypotension. Postural hypotension occurs when blood pressure drops when someone stands up from sitting or lying down. Whether it was caused by tramadol is unclear.

Tramadol doesn’t seem to interact with high blood pressure medications, but other interactions are possible.

Taking other drugs can interfere with the way your body processes tramadol or cause other interactions. For instance, tramadol is not a blood thinner, but there are some reports that it may interact with blood thinners, like warfarin.

Many drugs may interact with tramadol, including:

  • Certain antidepressants
  • Appetite suppressant drugs
  • Certain antifungal medications
  • Certain antibiotics
  • Other opioids
  • Seizure medications
  • Some migraine medications
  • Malaria drugs
  • Some heart medications
  • Blood thinners

While blood pressure changes are not a common side effect of tramadol, some medication interactions can lead to extreme changes in blood pressure.

There are many possible drug interactions for tramadol that can be discussed with your doctor and searched on a drug interactions checker before taking the drug.

People taking tramadol should avoid drinking any alcohol or taking additional opioid medications.

Additionally, there are some people who generally should not take tramadol. These include:

  • People who are allergic to the drug
  • People with slowed breathing
  • People who have acute or severe asthma

Tramadol is the drug’s generic name. It’s sold under several brand names, including:

  • ConZip
  • Qdolo
  • Ultracet
  • Ultram
  • Ultram ER


  1. Food and Drug Administration (FDA). Highlights of prescribing information: Tramadol hydrochloride extended-release capsules. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/022370s000lbl.pdf. [Accessed September 2, 2020].
  2. MedlinePlus. Tramadol. https://medlineplus.gov/druginfo/meds/a695011.html. [Accessed September 18, 2020].
  3. Food and Drug Administration (FDA). Highlights of prescribing information: Ultram (tramadol hydrochloride) tablets. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/020281s041lbl.pdf. [Accessed September 9, 2020].
  4. Drugs.com. Drug Interactions between Cymbalta and tramadol. Available at: https://www.drugs.com/drug-interactions/cymbalta-with-tramadol-949-2273-2221-0.html. [Accessed September 18, 2020].
  5. Drugs.com. Tramadol tablets. September 1, 2019. Available at: https://www.drugs.com/pro/tramadol-tablets.html#s-34090-1. [Accessed September 14, 2020].

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Drug information

  • Tramadol Information for Consumers
  • Tramadol prescribing info & package insert
    (for Health Professionals)
  • Side Effects of Tramadol

Related support groups

  • Tramadol
    (476 questions, 2,654 members)

Medical Disclaimer

Evidence For Tramadol-Warfarin Interaction

Published: October 2006

This article is more than five years old. Some content may no
longer be current.

Prescriber Update 27(2): 23-24.

October 2006

Ruth Savage, Medical Assessor, CARM, New Zealand Pharmacovigilance
Centre, Dunedin

Local and international case reports provide evidence of an interaction
between oral tramadol and warfarin in some individuals, leading to an elevated
International Normalised Ratio (INR) and in some instances bruising or haemorrhage. 
The mechanism has not been determined.  The interaction usually occurs
3-4 days after tramadol is commenced in patients stabilised on warfarin. 
The decrease in INR after tramadol is withdrawn may take several days. 
Where it is necessary to prescribe tramadol with warfarin there should be
close monitoring of the INR, especially during the first week of treatment
with tramadol.

CARM reports show marked increases in INR

Up to 31 July 2006, the Centre for Adverse Reactions Monitoring (CARM)
had received a total of 116 reports of suspected adverse reactions to tramadol.  
Three of these reports were of increased International Normalised Ratio
(INR), ranging from 7.0 to 12.3 occurring when oral tramadol was given to
patients taking warfarin.  Two patients were symptomatic: one with
petechiae and one with melaena.  Onset time after tramadol was commenced
was one, two and seven days.  A fourth patient taking warfarin was
found to have bruising and a haematoma eight days after commencing tramadol.

The extent to which tramadol contributed to the elevated INR in the four
patients is not entirely clear as one patient may have taken an incorrect
dose of warfarin and the other three were also prescribed antibiotics. 
However, tramadol seemed the most likely cause in two of these cases.

Published case reports provide further evidence

Firmer evidence of an interaction with oral tramadol can be found in
two published case reports.1,2 
A 76-year-old man had been on a stable dose of warfarin for six months when
he developed purpura and was found to have an INR of 7. 3.  He had been
taking tramadol 50mg three times daily for one month.  There had been
no other changes to his prescribed medication, and he had not taken any
over-the-counter medicines.1  A 61-year-old
woman on a stable regime of medicines including warfarin had recently finished
taking tramadol 50mg six hourly for two weeks.  She presented with
extensive bruising of the right upper arm, and was found to have an INR
of 10.6.  Warfarin was withheld for three days until her INR reduced
sufficiently for the warfarin to be reinstated, although initially a lower
dose was required.2

Similar reports in Australia

Case reports published in 2004 by the Australian Adverse Drug Reactions
Advisory Committee (ADRAC) detail 11 reports of elevated INR or haemorrhage
when tramadol was taken with warfarin.3 
The median onset time after addition of tramadol to stabilised warfarin
therapy was four (range 3-7) days, with the exception of one outlier at
six weeks.   Five reports described recovery within 1-4 days of tramadol
being discontinued, with or without reduction in the dose of warfarin. 
Two patients, aged 76 and 88 years, died of haemorrhagic stroke.

The interaction may occur in a sub-group of patients

In a pharmacodynamic study4 of the effect
of oral tramadol on INR in 19 patients stabilised on phenprocoumon (a coumarin
anticoagulant), two patients had clinically significant increases in INR
to 6.0 and 7.3, respectively, while taking tramadol.  However, the
mean difference in INR for all participants did not reach statistical significance. 
The mechanism of the interaction is unclear, but these results suggest that
the interaction may be associated with a variation in metabolism and that
only a sub-group of patients will be affected.  This possibility is
supported by the small number of case reports in the Australian database
compared with total prescriptions for oral tramadol. 3

Increased INR monitoring necessary when tramadol prescribed
with warfarin

Although the mechanism has not been elucidated, there is evidence for
an interaction between oral tramadol and warfarin in some, but probably
not all, individuals.  The CARM case reports, where antibiotics were
also implicated, are a reminder that more than one interaction may be occurring. 
The interaction between tramadol and warfarin is documented in the product
information for tramadol.5-7 
It is unclear whether the interaction occurs with injectable tramadol.3

Close monitoring of the INR should be undertaken when it is necessary
to prescribe tramadol for patients taking warfarin, especially during the
first week of treatment with tramadol.

Competing interests (author): none declared.

  1. Scher ML, Huntington NH, Vitillo JA. Potential interaction
    between tramadol and warfarin. Ann Pharmacotherapy 1997;31:646-647.
  2. Sabbe JR, Sims PJ, Sims MH. Tramadol-warfarin interaction.
    Pharmacotherapy 1998;18(4):871-873.
  3. Adverse Drug Reactions Advisory Committee (ADRAC), Australia.
    Tramadol-warfarin interaction. ADRAC Bulletin 2004;23(4).
  4. Boeijinga JK, van Meegan E, van den Ende R. Lack of interaction
    between tramadol and coumarins. J Clin Pharmacol 1998;38:966-970.
  5. CSL (New Zealand) Limited. Tramal (tramadol) data sheet
    October 2005.
  6. Pharmaco (NZ) Limited. Zytram BD (tramadol) data sheet
    20 February 2006. www.medsafe.govt.nz/profs/Datasheet/z/ZytramBDtab.pdf
  7. AFT Pharmaceuticals Ltd. Tramadol data sheet 8 December
    2005. www.medsafe.govt.nz/profs/Datasheet/t/TramadolHydrochloridecap.