The use of azathioprine (AZA) in human medicine dates back to research conducted in 1975 that led to the development of several drugs, including 6-mercaptopurine. In 1958, it was shown that 6-mercaptopurine decreased the production of antibodies against earlier administered antigens, raising the hypothesis of an immunomodulatory effect. AZA is a prodrug that belongs to the thiopurine group of drugs that behave as purine analogs. After absorption, it is converted into 6-mercaptopurine. Subsequently, it can be degraded through various enzymatic pathways into inactive compounds and biologically active compounds related to the mechanism of action, which has been the subject of study to evaluate a possible antiviral effect. This study aims to examine the metabolism, mechanism of action, and antiviral potential of AZA and its derivatives, exploring AZA impact on antiviral targets and adverse effects through a narrative literature review. Ultimately, the review will provide insights into the antiviral mechanism, present evidence of its in vitro effectiveness against various DNA and RNA viruses, and suggest in vivo studies to further demonstrate its antiviral effects.

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

BACKGROUND: 5-Fluorouracil (5-FU) is an antimetabolite chemotherapy used for a variety of solid tumors. It has the potential to cause a wide spectrum of cardiotoxicity, ranging from asymptomatic electrocardiographic changes to cardiomyopathy and subsequent cardiac failure. Main body of the abstract: We present two descriptive cases of new-onset severe cardiomyopathy induced by 5-FU followed by a review of the literature.
CONCLUSIONS: Our case series emphasizes the importance of early recognition of this rare complication and prompt cessation of 5-FU, as cardiac dysfunction in this context is potentially reversible.

Hydroxyurea (HU) is being used for patients with transfusion-dependent β-thalassemia major (β-TM) as well as non transfusion-dependent β-TM. As controversy exists regarding efficacy and safety of HU, we searched the published literature on efficacy, effectiveness and toxicity of HU in patients with β-TM. The research sources we used were: Medline, SID, PubMed, Scopus, Request, Web of Knowledge, Springer, Ovid, Cochrane searched up to October 2012. Using search terms sensitive to studies of clinical trials combined with searches on terms related to thalassemia and HU. We selected studies on randomized trials, quasi experimental trials (before and after design), case reports (with 1-5 cases), side effect studies in patients with β-TM, studies related to the mechanism of action and toxicity when used in patients with other hemoglobinopathies. We researched studies in English and Persian. Eligible articles were reviewed by two independent reviewers. Patient\'s characteristics, duration of trial, outcome and side effects were extracted. The main outcomes were synthesized under a random-effects model. Heterogeneity was assessed using the Q statistic, Tau(2) and I(2). Subgroup analyses were performed and the statistics data (STATA) software used. More than 500 articles were reviewed. No randomized clinical trial was found. Seventeen trials with before and after designs were found, 16 case reports (1-5 cases), 19 articles for mechanism of action and 16 studies for side effects were published from 1969 to October 2012. Hemoglobin levels after treatment showed modest but significant increase in non transfusion-dependent β-TM (p < 0.0001) and in transfusion-dependent β-TM (p < 0.0001).