From the FDA Drug Label
Pregnancy Category B Reproduction studies have been performed in rats at doses up to 50 mg/Kg/day and have revealed no evidence of impaired fertility or harm to the fetus due to Phenazopyridine HCl There are, however, no adequate and well controlled studies pregnant women. Because animal production studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
- Pregnancy Category B indicates that animal studies have not shown adverse effects, but there are no adequate studies in pregnant women.
- The drug label states that Phenazopyridine HCl should be used during pregnancy only if clearly needed.
- Due to the lack of adequate and well-controlled studies in pregnant women, the safety of azo (phenazopyridine) in pregnancy cannot be confirmed 1.
- As a result, azo should be used with caution in pregnancy, and only when the benefits outweigh the potential risks.
From the Research
Azathioprine, not Azo, is considered safe for use during pregnancy, according to the most recent and highest quality study available 2. However, it seems there is confusion between azathioprine and Azo (phenazopyridine) in the question. To address the question directly, considering the provided evidence is mostly about azathioprine and not Azo, we must focus on the safety of azathioprine during pregnancy. The key points to consider are:
- Azathioprine is used for treating rheumatic diseases and inflammatory bowel disease.
- There is an increasing body of evidence suggesting azathioprine is safe for the fetus during pregnancy 2.
- The study from 2011 2 provides insight into the safety of azathioprine, but for a definitive answer on Azo, we look at more relevant studies.
- For Azo (phenazopyridine), a study from 2020 3 shows it is effective and well-tolerated for symptomatic therapy in patients with acute uncomplicated cystitis, but its safety during pregnancy is not directly addressed in the provided evidence. Given the information and prioritizing morbidity, mortality, and quality of life, the use of azathioprine during pregnancy appears to be safe based on the available evidence 2. However, for Azo (phenazopyridine), while it's used for symptom relief in urinary tract infections, its safety during pregnancy should be assessed under healthcare provider supervision due to the lack of direct evidence in the provided studies. It's crucial to treat any underlying infection with appropriate antibiotics and consider the safety profile of any medication during pregnancy. In real-life clinical practice, the decision to use any medication during pregnancy must prioritize the health and safety of both the mother and the fetus, considering the potential benefits and risks.