Hematological Safety of Dipyrone Versus Paracetamol After Dental Extractions

Hematological Alterations Associated With the Use of Dipyrone Versus Paracetamol After Dental Extractions: a Double-blind, Randomized Clinical Trial

The goal of this clinical trial is to compare the safety of dipyrone and paracetamol when used for pain relief after dental extractions in adults. The study will focus on changes in blood cell counts and will also evaluate liver and kidney function and possible side effects. The main questions it aims to answer are:

• Do dipyrone and paracetamol have different effects on blood cell counts after dental extractions?
• Do participants exhibit hepatic and renal alterations?
• What side effects do participants experience when taking these medications?

Researchers will compare dipyrone and paracetamol to learn more about their safety after dental extractions.

Participants will:

• Undergo two dental extractions, one during each study period, involving teeth that already need to be removed
• Take dipyrone 500 mg or paracetamol 750 mg in a random order, taking two capsules every 6 hours for 7 days during each period
• Have at least 21 days between the two study periods
• Have three blood collections: one before the first extraction and one on the eighth day after each extraction
• Keep a diary of their pain, medication use, and possible side effects
• Have their blood pressure checked and attend clinic visits and telephone follow-ups to monitor their health

Study Overview

• Status: Recruiting
• Conditions: Agranulocytosis; Side Effects; Hepatic Complications; Hematologic Test; Renal Effects; Blood Pressure Monitoring
• Intervention / Treatment: Drug: Dipyrone administration; Drug: Paracetamol (drug); Procedure: blood sampling

Detailed Description

Dental extractions are commonly followed by pain, and medications such as dipyrone and paracetamol are used to help relieve this pain. Although both medications are widely used, it is important to better understand their safety, particularly their possible effects on blood cell counts.

This clinical trial aims to compare the safety of dipyrone and paracetamol in adults undergoing dental extractions. The main focus is to evaluate changes in blood cell counts, including white blood cells, neutrophils, red blood cells, and platelets. The study will also assess blood tests related to liver and kidney function, changes in blood pressure and possible side effects during treatment.

Participants will undergo two dental extractions, one during each study period, involving teeth that already require removal. The order in which participants receive the medications will be determined randomly. During one study period, participants will receive dipyrone 500 mg per dose, and during the other, they will receive paracetamol 750 mg per dose. Each dose will consist of two capsules. The medications will be provided in identical capsules and will be prepared by a compounding pharmacy in Brazil, according to the study protocol. Neither participants nor researchers will know which medication is being used during each period. Each treatment period will last 7 days, with two capsules taken every 6 hours, according to the study protocol. The two study periods will be separated by at least 21 days.

Blood samples will be collected three times: before the first dental extraction and on the eighth day after each extraction. These tests will allow researchers to compare blood cell counts and other laboratory results before and after each medication period. Participants will also record their pain levels, medication use, and possible side effects in a diary. Blood pressure will be monitored, and clinical assessments and telephone contacts will be used to follow participants' health and identify possible adverse reactions.

By comparing the results obtained during the two treatment periods, researchers hope to improve understanding of the safety of dipyrone and paracetamol when used after dental extractions. The findings may contribute to evidence-based decisions about pain management following dental surgery.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Phase 4

Contacts and Locations

Study Locations

• Brazil
  • Minas Gerais
    • Juiz de Fora, Minas Gerais, Brazil, 36036-900
      • Recruiting
      • Faculty of Dentistry at the Federal University of Juiz de Fora (UFJF)
      • Contact: Matheus F Carvalho, PhD; Phone Number: + 55 (32) 98811-3967; Email: matheus.furtado@ufjf.br
      • Contact: Alice F Fernandes; Phone Number: + 55 (32) 99863-3990; Email: aliceferreira.fernandes@estudante.ufjf.br

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy patients of both sexes, aged 18 to 60 years
• Indication for bilateral tooth extraction in similar positions

Exclusion Criteria:

• History of allergy to dipyrone or paracetamol.
• Insufficient or improperly completed study records.
• Failure to return for the second tooth extraction.
• Use of warfarin, bupropion, efavirenz, methadone, cyclosporine, tacrolimus, sertraline, valproate, methotrexate, acetylsalicylic acid, or other non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, or corticosteroids on a continuous basis (for 7 days or longer) prior to surgery.
• Systemic conditions that could interfere with hematological outcomes, including diagnosed hematological disorders, coagulopathies, severe liver or kidney disease, or active autoimmune diseases at the time of the appointment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm 1: Paracetamol followed by dipyrone; Participants receive paracetamol 750 mg per dose during the first treatment period, following the first dental extraction, and dipyrone 500 mg per dose during the second treatment period, following the second dental extraction, according to the randomized crossover sequence. Each treatment is administered as two capsules every 6 hours for 7 days, with a washout period between treatments.	Drug: Dipyrone administration; Dipyrone 500 mg per dose, administered orally as two capsules every 6 hours for 7 days following dental extraction, according to the study protocol.; Drug: Paracetamol (drug); Paracetamol 750 mg per dose, administered orally as two capsules every 6 hours for 7 days following dental extraction, according to the study protocol; Procedure: blood sampling; Blood samples will be collected at three time points: before the first dental extraction, on the eighth day after the first treatment period, and on the eighth day after the second treatment period.
Experimental: Dipyrone followed by paracetamol; Participants receive dipyrone 500 mg per dose during the first treatment period, following the first dental extraction, and paracetamol 750 mg per dose during the second treatment period, following the second dental extraction, according to the randomized crossover sequence. Each treatment is administered as two capsules every 6 hours for 7 days, with a washout period between treatments.	Drug: Dipyrone administration; Dipyrone 500 mg per dose, administered orally as two capsules every 6 hours for 7 days following dental extraction, according to the study protocol.; Drug: Paracetamol (drug); Paracetamol 750 mg per dose, administered orally as two capsules every 6 hours for 7 days following dental extraction, according to the study protocol; Procedure: blood sampling; Blood samples will be collected at three time points: before the first dental extraction, on the eighth day after the first treatment period, and on the eighth day after the second treatment period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
White Blood Cell Parameters.	Total leukocyte count and neutrophil count will be assessed through blood samples and reported as cells/mm³, to evaluate changes following treatment with dipyrone and paracetamol after dental extractions.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Hemoglobin Level.	Hemoglobin level will be assessed in blood samples, and reported as g/dL, to evaluate changes following treatment with dipyrone and paracetamol after dental extractions.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Hematocrit.	Hematocrit will be assessed in blood samples, and reported as %, to evaluate changes following treatment with dipyrone and paracetamol after dental extractions.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Platelet Count	Platelet count will be assessed in blood samples, and reported as cells/mm³, to evaluate changes following treatment with dipyrone and paracetamol after dental extractions.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Liver Function Biomarkers.	Changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and alkaline phosphatase levels will be assessed through blood samples collected during the study, and reported as U/L.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Changes in Kidney Function Biomarkers.	Changes in creatinine and urea levels will be assessed through blood samples collected during the study, and reported as mg/dL.	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Adverse Reactions.	Occurrence of adverse reactions associated with dipyrone and paracetamol will be monitored and recorded during each postoperative treatment period.	Daily, from day 1 to day 7 after each dental extraction.
Systolic Blood Pressure	Systolic blood pressure measurements will be recorded to evaluate changes during treatment with dipyrone and paracetamol after dental extractions, and reported as mmHg	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.
Diastolic Blood Pressure.	Diastolic blood pressure measurements will be recorded to evaluate changes during treatment with dipyrone and paracetamol after dental extractions, and reported as mmHg	Before the first dental extraction, day 8 after the first dental extraction, and day 8 after the second dental extraction.

Collaborators and Investigators

• Sponsor: Matheus Furtado de Carvalho

Publications and helpful links

General Publications

• Watkins PB, Kaplowitz N, Slattery JT, Colonese CR, Colucci SV, Stewart PW, Harris SC. Aminotransferase elevations in healthy adults receiving 4 grams of acetaminophen daily: a randomized controlled trial. JAMA. 2006 Jul 5;296(1):87-93. doi: 10.1001/jama.296.1.87.
• Fidelis GFS, Dagli-Hernandez C, Martinelli RP, Marzuki JE, Baharuddin B, Yue QY, Edwards B, Pincinato EC, Moriel P. Pharmacogenetics of metamizole-induced agranulocytosis: a systematic review and drug regulation implications. Front Pharmacol. 2025 Sep 24;16:1624044. doi: 10.3389/fphar.2025.1624044. eCollection 2025.
• Zinzi A, Gaio M, Ruggiero D, Riccardi C, Cagnotta C, Pentella C, Capuano A, Rafaniello C. A systematic review and pharmacovigilance analysis of the risk of agranulocytosis associated with metamizole use. Sci Rep. 2025 Nov 28;15(1):42796. doi: 10.1038/s41598-025-27009-6.
• Tsang WH, Chan CK, Tse ML. Paracetamol-induced hepatotoxicity after normal therapeutic doses in the Hong Kong Chinese population. Hong Kong Med J. 2024 Oct;30(5):355-361. doi: 10.12809/hkmj2311194. Epub 2024 Oct 10.
• Blaser LS, Duthaler U, Bouitbir J, Leuppi-Taegtmeyer AB, Liakoni E, Dolf R, Mayr M, Drewe J, Krahenbuhl S, Haschke M. Comparative Effects of Metamizole (Dipyrone) and Naproxen on Renal Function and Prostacyclin Synthesis in Salt-Depleted Healthy Subjects - A Randomized Controlled Parallel Group Study. Front Pharmacol. 2021 Sep 7;12:620635. doi: 10.3389/fphar.2021.620635. eCollection 2021.
• Risks of agranulocytosis and aplastic anemia. A first report of their relation to drug use with special reference to analgesics. The International Agranulocytosis and Aplastic Anemia Study. JAMA. 1986 Oct 3;256(13):1749-57.
• ANDRADE, E. D. Terapêutica Medicamentosa em Odontologia. 2ª ed. São Paulo: Artes Médicas; 2006
• de Souza EC, Matos DM, Viana MR, Alvim MCO, Bonfante HL, Pinto AF, Nascimento JWL. Evaluation of hematological alterations after therapeutic use of dipyrone in healthy adults: a prospective study. J Basic Clin Physiol Pharmacol. 2018 Jul 26;29(4):385-390. doi: 10.1515/jbcpp-2017-0037.

Study record dates

Study Major Dates

• Study Start (Estimated): November 13, 2026
• Primary Completion (Estimated): July 31, 2027
• Study Completion (Estimated): July 31, 2027

Study Registration Dates

• First Submitted: October 27, 2026
• First Submitted That Met QC Criteria: November 4, 2026
• First Posted (Actual): November 5, 2026

Study Record Updates

• Last Update Posted (Actual): November 5, 2026
• Last Update Submitted That Met QC Criteria: November 4, 2026
• Last Verified: October 1, 2026

More Information

Terms related to this study

• Keywords: Paracetamol; Dipyrone; Hematological tests
• Additional Relevant MeSH Terms: Cytopenia; Leukocyte Disorders; Hematologic Diseases; Leukopenia; Hemic and Lymphatic Diseases; Agranulocytosis; Organic Chemicals; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Anilides; Amides; Aniline Compounds; Amines; Acetanilides; Acetaminophen; Blood Specimen Collection; Pharmaceutical Preparations
• Other Study ID Numbers: 97343326.1.0000.5147

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

Individual participant data will not be shared with researchers outside the study team. Data access will be restricted to authorized researchers, and participant confidentiality will be protected through data coding, password-protected digital files, and restricted access to physical documents, in accordance with applicable data protection requirements.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No