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7 Interactions found for:

allopurinol and Lasix
Interactions Summary
  • 4 Major
  • 3 Moderate
  • 0 Minor
  • allopurinol
  • Lasix

Drug Interactions

Moderate
Allopurinol + Lasix

The following applies to the ingredients: Allopurinol and Furosemide (found in Lasix)

MONITOR: Coadministration with furosemide may increase the plasma concentrations of oxypurinol, the active metabolite of allopurinol, and the serum urate concentrations. It is unclear if all diuretics have the same effect on oxypurinol. However, other diuretics (e.g., torsemide, bumetanide, ethacrynic acid) are also known to increase serum urate concentrations thus lowering the efficacy of allopurinol. Higher levels of oxypurinol have been associated with an increased risk of allopurinol hypersensitivity reactions, such as skin rash, drug reaction with eosinophilia and systemic symptoms (DRESS) and severe cutaneous adverse reactions (SCAR). Renal impairment has been demonstrated to also be a risk factor for allopurinol hypersensitivity. One proposed mechanism for this interaction is related to the interference of furosemide with the renal clearance of oxypurinol, although the exact details are still unclear.

MANAGEMENT: Caution is recommended when diuretics and allopurinol are coadministered. Patients should be monitored for increased toxicity as well as reduced efficacy, depending on the diuretic agent administered. Particularly when coadministered with furosemide, patients should be advised to stop allopurinol and promptly report any signs of hypersensitivity, including rash, pruritus, fever, or chills.

References

  1. "Product Information. Allopurinol (Sandoz) (allopurinol)." Sandoz Pty Ltd (2024):
  2. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd (2021):
  3. "Product Information. Zyloprim (allopurinol)." AA Pharma Inc 248178 (2021):
  4. "Product Information. Allopurinol (allopurinol)." Actavis U.S. (Purepac Pharmaceutical Company) (2024):
  5. stamp l "Allopurinol hypersensitivity: investigating the cause and minimizing the risk" Nat Rev Rheumatol 12 (2015): 235-242
  6. stamp l "Furosemide increases plasma oxypurinol without lowering serum urate-a complex drug interaction: implications for clinical practice" Rheumatology (Oxford) 51 (2012): 1670-1676

Drug and Food Interactions

Moderate
Allopurinol + Food

The following applies to the ingredients: Allopurinol

ADJUST DOSING INTERVAL: The tolerability of allopurinol may be improved by giving it after a meal. Additionally, when the dose is greater than 300 mg, dividing the total daily dose into smaller doses administered more often may be appropriate to help minimize gastrointestinal irritation.

MONITOR: Concomitant use of allopurinol with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: To improve tolerability, some manufacturers suggest administering allopurinol after a meal. Additionally, if the daily dose is greater than 300 mg, administering allopurinol in divided doses may help reduce gastrointestinal intolerance. Patients should also be counseled to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.

References

  1. "Product Information. Allopurinol (Sandoz) (allopurinol)." Sandoz Pty Ltd (2024):
  2. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd (2021):
  3. "Product Information. Zyloprim (allopurinol)." AA Pharma Inc 248178 (2021):
  4. "Product Information. Allopurinol (allopurinol)." Actavis U.S. (Purepac Pharmaceutical Company) (2024):

Moderate
Lasix + Food

The following applies to the ingredients: Furosemide (found in Lasix)

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution and close monitoring for development of hypotension is advised during coadministration of these agents. Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients should also avoid driving or operating hazardous machinery until they know how the medications affect them.

References

  1. Sternbach H "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol 11 (1991): 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med 101 (1984): 498-9
  3. Feder R "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry 52 (1991): 139
  4. Ellison JM, Milofsky JE, Ely E "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry 51 (1990): 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit 23 (2001): 435-40
  6. Cerner Multum, Inc. "Australian Product Information." O 0
  7. Pacher P, Kecskemeti V "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des 10 (2004): 2463-75
  8. Andrews C, Pinner G "Postural hypotension induced by paroxetine." BMJ 316 (1998): 595
  9. "Product Information. Buprenorphine (buprenorphine)." G.L. Pharma UK Ltd (2023):
  10. "Product Information. Temgesic (buprenorphine)." Reckitt Benckiser Pty Ltd (2023):

Drug and Pregnancy Interactions

The following applies to the ingredients: Allopurinol

Safety has not been established.
-According to some authorities: This drug is only recommended for use during pregnancy when there are no safer alternatives and the benefit outweighs the risk.

AU TGA pregnancy category: B2
US FDA pregnancy category: Not assigned

Risk Summary: Based on findings in animals, this drug may cause fetal harm.

Comments:
-Animals exposed to this drug have shown negative developmental effects.
-Placental transfer of this drug and its metabolite have been reported.
-The available data on the use of this drug during pregnancy is limited and inconclusive. Pregnant women should be apprised of the potential risk to the fetus.
-This drug has been used widely for many years without apparent harmful effects.
-Infertility and impotence in men rarely occur during treatment with this drug, and studies have not confirmed an association with it.

Animal studies have failed to reveal evidence of fetotoxicity or teratogenicity. However, intraperitoneal administration of this drug in pregnant mice on gestation days 10 or 13 produced significant increases in fetal deaths and teratogenic effects (cleft palate, harelip, and digital defects). In another study, this drug after oral administration to pregnant rats during organogenesis caused embryonic resorptions, growth retardation, decreased fetal weight, and skeletal, liver, kidney, and brain abnormalities. A 2013 report analyzed 31 pregnancies exposed to this drug during the first trimester, finding that major birth defects and miscarriages were within the general population's range, but one child had severe defects. There is insufficient data in human pregnancy.

AU TGA pregnancy category B2: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. "Product Information. Allosig (allopurinol)." Arrow Pharma Pty Ltd 18 March 2025 (2025):
  2. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd 19 Feb 2025 (2025):
  3. "Product Information. Aloprim (allopurinol)." Mylan Institutional LLC 2/2022 (2022):
  4. "Product Information. Zyloprim (allopurinol)." Casper Pharma LLC 9/2023 (2023):
  5. "Product Information. Allopurinol (allopurinol)." Leading Pharma, LLC 9/2024 (2024):

The following applies to the ingredients: Furosemide (found in Lasix)

This drug should not be used during pregnancy unless the benefit outweighs the risk to the fetus.
-According to some authorities: Use is contraindicated.

AU TGA pregnancy category: C
US FDA pregnancy category: Not assigned

Risk summary: No data are available on the use of this drug in pregnant women to inform a drug-related risk.

Comments: Use of this drug during pregnancy requires monitoring of electrolytes, hematocrit, and fetal growth.

Animal studies have revealed evidence of fetolethality. There are no controlled data in human pregnancy.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. "Product Information. Lasix (furosemide)." sanofi-aventis PROD (2007):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Lasix (furosemide)." Validus Pharmaceuticals LLC (2018):
  5. "Product Information. Furoscix (furosemide)." scPharmaceuticals (2025):

Drug and Breastfeeding Interactions

The following applies to the ingredients: Allopurinol

Breastfeeding is not recommended during use of this drug and for 1 week after the last dose.

Excreted into human milk: Yes

Comments:
-This drug and its active metabolite were detected in human milk.
-There was no report of effects of this drug on the nursing infant or on milk production.
-If the mother requires this drug, she does not have to stop nursing, but the nursing infant should be monitored for allergic reactions (such as rash) and undergo periodic CBC and differential blood counts.

References

  1. Bethesda (MD): National Institute of Child Health and Human Development (US) "Allopurinol - Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501198/" (2025):
  2. "Product Information. Allosig (allopurinol)." Arrow Pharma Pty Ltd 18 March 2025 (2025):
  3. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd 19 Feb 2025 (2025):
  4. "Product Information. Aloprim (allopurinol)." Mylan Institutional LLC 2/2022 (2022):
  5. "Product Information. Zyloprim (allopurinol)." Casper Pharma LLC 9/2023 (2023):
  6. "Product Information. Allopurinol (allopurinol)." Leading Pharma, LLC 9/2024 (2024):

The following applies to the ingredients: Furosemide (found in Lasix)

Caution is recommended as use is contraindicated according to some authorities.

Excreted into human milk: Yes

Comments: The effects in the nursing infant are unknown.

References

  1. "Product Information. Lasix (furosemide)." sanofi-aventis PROD (2007):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

Therapeutic Duplication Warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Switch to: Consumer Interactions

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

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