The goal of this randomized, triple-masked clinical trial is to compare the effectiveness and safety of the use of ibuprofen versus dipyrone for postoperative analgesia in postpartum women with preeclampsia undergoing cesarean section.

The main question it aims to answer are:

• Postoperative pain is similar;
• The frequency of acute kidney injury is similar.

Researchers will compare one group that will receive dipyrone and the other group that will receive ibuprofen to see if Postoperative pain are different between groups or development of acute kidney injury each group is different.

Specific objectives

In postpartum women with preeclampsia undergoing cesarean section randomized to receive treatment with ibuprofen versus dipyrone for postoperative analgesia, compare:

primary outcomes

1. Postoperative pain (mild, moderate, severe by visual analogue scale)
2. Development of acute kidney injury (serum creatinine 1.5 to 1.9 times baseline, or increase in serum creatinine by ≥0.3 mg/dL, or decrease in urine output to <0.5 mL/kg/ hour for six to 12 hours).

secondary outcomes

1. Average reduction of visual analogue scale scores;

2 Reduction of mean scores by algometer;

3. Need for rescue analgesic;

4. User satisfaction with the Likert scale;

5. Basic laboratory tests and their evolution: urea, creatine, uric acid, saline, potassium and chlorine, lactic dehydrogenase (DHL), aspartate transferase (AST), alanine transferase (ALT), total and fractions bilirubin and plaque;

6. Evolution of blood pressure in the puerperium;

7. Number of hypertensive peaks;

8. Need for maintenance antihypertensive treatment and number of drugs;

9. Allergic reactions;

10. Gastrointestinal side effects;

11. Time between postoperative and unassisted ambulation;

12. Length of hospital stay;

13. Compound maternal morbidity (eclampsia, acute weight edema, HELLP, difficulty hypertension, intracranial hemorrhage, renal function control and others);

14. Maternal death;

15. Costs related to analgesic medications.

The sample is 74 patients randomized into two groups: one group that will receive dipyrone and the other group that will receive ibuprofen. Randomization for the two groups will be performed according to a list of random numbers drawn up for that purpose by an employee who does not be involved with data collection, to ensure confidentiality in the allocation. From this list, sealed envelopes will be prepared, numbered sequentially, with each number, according to the randomization table, corresponding to the patient's group (dipyrone or ibuprofen).

For statistical analysis of the data, the domain statistical program will be used public Epi-info version 7, or higher versions. Tables will be distributed frequency distribution for categorical variables, calculating the mean and standard deviation of quantitative variables. Then, contingency tables will be used to determine the association of the independent variable (Ibuprofen versus dipyrone) with the dependent variables (Biological characteristics, obstetric features, Maternal clinical parameters at admission and during hospitalization, Maternal laboratory tests at the time of admission). For determination of the strength of association will be calculated as a measure of the risk (RR) and its 95% confidence interval. All p values will be two-tailed and in all stages of the analysis will be considered a level of significance 5%.

Inclusion Criteria:

• Puerperal women from 14 years of age diagnosed with preeclampsia with signs of severity Immediate postoperative period;
• Delivery attended at the Maternity from Instituto de Medicina Integral Prof Fernando Figueira.

Exclusion Criteria:

• Acute kidney disease (serum creatinine 1.5 to 1.9 times baseline, or increase in serum creatinine by ≥0.3 mg/dL, or decrease in urine output to <0.5 mL/kg/hour for six to 12 hours)
• Chronic kidney disease;
• Diabetes mellitus;
• Collagenoses;
• Sickle cell anemia;
• Patients who presented bleeding in the pre, trans and immediate postpartum periods;
• Antepartum or puerperal sepsis;
• Known contraindications to the use of NSAIDs and dipyrone;