Drug Database
AZ

azathioprine (azathioprine, Salix / Azasan / Azasan)

✓ Approved

Salix · Small Molecule · Small Molecule

What is azathioprine?

azathioprine is a small molecule developed by Salix. It is approved for therapeutic indications via oral (po).

Drug Profile

Brand Namesazathioprine, Salix, Azasan, Azasan
CompanySalix
Drug ClassSmall Molecule
RouteOral (PO)
StatusApproved
Sources: ClinicalTrials.gov, Salix

Therapeutic Indications

azathioprine is developed for 2 unique indications across 2 therapeutic areas.

Therapeutic AreaConditionPhase
Musculoskeletal and connective tissue disordersRheumatoid arthritis✓ Approved
Immune system disordersSolid organ transplant rejection✓ Approved

Related Research Articles

PubMedAnnals of hepatology2026-08-30

Porto-sinusoidal vascular disorder and sinusoidal obstructive syndrome in patients treated with thiopurines: a systematic review.

Curto Armando A, Lynch Erica Nicola EN, Tanturli Michele M, Iamello Rocco Gabriele RG et al.

Thiopurines (azathioprine [AZA], 6-mercaptopurine [6-MP], 6-thioguanine [6-TG]) can cause hepatic microvascular injury, presenting chronically as porto sinusoidal vascular disorder (PSVD) or related vascular lesions, or acutely as sinusoidal obstruction syndrome (SOS/veno-occlusive disease). We reviewed evidence across indications. We searched MEDLINE, EMBASE, Web of Science, SCOPUS, and the Cochrane Library from inception to 12 January 2026. We included studies reporting PSVD, SOS, or hepatic vascular lesions in thiopurine exposed patients, capturing historical terminology and distinguishing clinicopathological PSVD from isolated histopathological lesions. Of 980 records, 97 studies were included across inflammatory bowel disease, haematological disorders, transplantation, and rheumatological diseases. The strongest causal signal emerged in paediatric acute lymphoblastic leukaemia maintenance, where randomised comparisons showed excess hepatic vascular injury, predominantly SOS and portal hypertension phenotypes, with 6-TG versus 6-MP, prompting protocol amendments and limiting prolonged 6-TG use. Outside haematology, evidence for AZA/6-MP associated PSVD and related vascular lesions came mainly from observational cohorts and case reports. PSVD presented insidiously with preserved synthetic function; early clues included unexplained thrombocytopenia or splenomegaly, with progression to varices, ascites, portal vein thrombosis, and portal-hypertension complications. Dose/exposure intensity and host susceptibility modified risk, supporting a plausible continuum between acute and chronic phenotypes, although direct evidence of progression from SOS to PSVD remains limited. Thiopurines cause a spectrum of hepatic microvascular injury. Evidence most strongly implicates 6-TG, whereas evidence for AZA/6-MP-associated PSVD and related vascular lesions is less consistent but relevant. New thrombocytopenia or splenomegaly should prompt evaluation for portal hypertension; thiopurine withdrawal is recommended when PSVD/SOS is suspected. Thiopurines (azathioprine [AZA], 6-mercaptopurine [6-MP], 6-thioguanine [6-TG]) can cause hepatic microvascular injury, which may present chronically as porto-sinusoidal vascular disorder (PSVD) or related vascular lesions, or acutely as sinusoidal obstruction syndrome (SOS/veno-occlusive disease). We systematically reviewed evidence across all clinical indications. We searched MEDLINE (PubMed), EMBASE, Web of Science Core Collection, SCOPUS, and the Cochrane Library from inception to 12 January 2026. We included original studies (case reports/series, observational studies, clinical trials) reporting PSVD or SOS or relevant hepatic vascular lesions historically associated with these entities in thiopurine-exposed patients, capturing historical terminology and distinguishing a clinicopathological diagnosis of PSVD from reports limited to individual histopathological vascular lesions. From 980 records, 97 studies were included across inflammatory bowel disease, haematological disorders, transplant recipients, rheumatological diseases and other indications. The strongest causal signal emerged in paediatric acute lymphoblastic leukaemia maintenance therapy: randomised comparisons consistently showed a marked excess of hepatic vascular injury, predominantly SOS and portal-hypertension phenotype, with 6-TG versus 6-MP, prompting protocol amendments and limiting prolonged 6-TG use in that setting. Outside haematology, evidence for AZA/6-MP-associated PSVD and related vascular lesions came mainly from observational cohorts and case-based evidence. Clinically overt PSVD typically presented insidiously with preserved liver synthetic function. Early clues included unexplained thrombocytopenia or splenomegaly, with potential progression to varices, ascites, portal vein thrombosis (PVT) and other portal-hypertension complications. Overall, dose/exposure intensity and host susceptibility appeared to modify risk, consistent with a plausible pathophysiological continuum between distinct acute and chronic phenotypes; however direct evidence of progression from SOS to PSVD remains limited. Thiopurines can precipitate a spectrum of hepatic microvascular injury. Evidence most strongly implicates 6-TG (dose/exposure dependent), whereas AZA/6-MP-associated PSVD and related vascular lesions is less consistent but remains clinically relevant. In exposed patients, new thrombocytopenia or splenomegaly should trigger evaluation for portal hypertension; thiopurine withdrawal is recommended when PSVD/SOS is suspected.

PMID 42669325
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PubMedJournal of clinical medicine2026-08-27

Endoscopic Activity Prediction in Ulcerative Colitis Using Hemogram-Derived Inflammatory Indices: Impact of Azathioprine Use on Diagnostic Performance.

Kaya Muhammed M, Evren Gökhan G, Durak İbrahim İ, Düzenli Tolga T et al.

Objective: In ulcerative colitis (UC), endoscopic assessment remains central to disease monitoring, but repeated colonoscopy is invasive and resource-intensive. This study evaluated the association and discriminatory performance of the systemic immune-inflammation index (SII; platelet × neutrophil/lymphocyte) and the hemoglobin-albumin-lymphocyte-platelet (HALP; hemoglobin × albumin × lymphocyte/platelet) score for endoscopic activity in UC and explored whether azathioprine use modified these associations. Methods: Among 428 retrospectively reviewed patients with UC, 218 met the inclusion criteria. Mayo-defined activity (endoscopic score ≥ 2) and Rachmilewitz EAI-defined activity (score ≥ 4) were analyzed as separate outcomes. Laboratory parameters were compared between active disease and remission groups. Receiver operating characteristic (ROC) analyses, multivariable logistic regression, sensitivity analyses accounting for disease duration and treatment category, and azathioprine interaction analyses were performed. Results: According to the Mayo and Rachmilewitz EAI definitions, 80 (36.7%) and 150 (68.8%) patients, respectively, had active disease. For Mayo-defined activity, CRP showed the highest discrimination (AUC = 0.720), followed by SII (AUC = 0.692), whereas HALP showed limited discrimination (AUC = 0.598). In the primary multivariable Mayo model, CRP, SII, younger age, and male sex were independently associated with activity, whereas HALP and azathioprine use were not. Adding SII to CRP produced only a small numerical increase in AUC (0.720 to 0.752), and adding HALP produced essentially no further change. No significant interaction between azathioprine use and SII or HALP was identified. Conclusion: SII was associated with endoscopic activity but showed only modest discriminatory performance, while HALP had limited discriminatory and independent predictive value. CRP remained the strongest individual biomarker. SII and HALP should therefore be interpreted as adjunctive inflammatory indices rather than substitutes for established biomarkers or endoscopic assessment.

PMID 42652868
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PubMedBiomolecules2026-08-27

Risk of Adverse Pregnancy Outcomes in Patients with Non-Communicable, Chronic Inflammatory Barrier Diseases Under Systemic Treatment: A Large-Scale Retrospective Cohort Study.

Brouer Inga Catharina IC, Zani Aida A, Curman Philip P, Ludwig Ralf J RJ et al.

Chronic inflammatory barrier diseases (CIBDs) affect many women of reproductive age, yet the safety of biologics during pregnancy remains inadequately investigated. This retrospective cohort study used the US Collaborative Network of TriNetX to evaluate the risk of adverse pregnancy outcomes (APOs) among women with CIBD receiving tumor necrosis factor inhibitors (TNFis), interleukin-23 inhibitors (IL-23is), or conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), compared with untreated CIBD controls and the general pregnant population. Among 1842 pregnant women with CIBD receiving systemic therapy, 1188 were exposed to TNFis, 170 to IL-23is, 370 to azathioprine (csDMARD), and 114 to methotrexate (MTX) (csDMARD). The incidence of any APO ranged from 11% in untreated CIBD controls to 19% with ustekinumab (IL-12/23i). Among treatment groups, rates were 17% with TNFis, 18% with IL-23is, 13% with azathioprine, and 15% with MTX, compared with 17% in the general pregnant population. APO rates were comparable between the overall TNFi group and the TNFi group excluding certolizumab pegol (CZP) (TNFi). In the only non-exploratory comparison, TNFi exposure was associated with higher risks of (pre-)eclampsia and hypertension but a lower risk of abortion or intrauterine death versus CIBD controls, with no significant difference for overall APO. No treatment group showed a markedly increased overall APO risk, supporting tailored decision-making that balances the consequences of uncontrolled maternal disease against individual treatment-associated risks.

PMID 42650751
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PubMedMedicina2026-08-27

[Chronic immunomodulatory treatment in MOGAD: Experience in Latin America].

Savransky Andrea A

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune disorder of the central nervous system that predominantly affects children and young adults and presents a heterogeneous clinical spectrum. Disability in MOGAD is mainly associated with relapses. Treatment of MOGAD includes management of the acute episode and, in selected cases, the use of chronic immunomodulatory therapy to prevent relapses and sequelae. Currently, there are no therapeutic guidelines based on randomized clinical trials for MOGAD. Among the most commonly used options are oral immunosuppressants such as azathioprine and mycophenolate mofetil, intravenous immunoglobulin, rituximab, and, more recently, IL-6 pathway inhibitors such as tocilizumab. In Latin America, the management of MOGAD presents particular challenges related to access to high-cost therapies and the heterogeneity of healthcare systems.

PMID 42659552
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PubMedReumatismo2026-08-27

Anifrolumab as a therapeutic option in mixed connective tissue disease with autoimmune cytopenia: a case report and narrative review of the literature.

Italiano Noemi N, Perrotta Fabio Massimo FM, Fatica Mauro M, Lubrano Ennio E

Mixed connective tissue disease (MCTD) represents a complex autoimmune condition characterized by vasculopathy, fibrosis, and immune dysregulation. Autoimmune cytopenias are rare but clinically significant complications that increase morbidity and complicate management of these diseases. Current therapies, including glucocorticoids and conventional immunosuppressants, may be limited by intolerance or inadequate hematologic response. Type I interferon (IFN) signaling has emerged as a key pathogenic pathway, and its blockade represents a novel therapeutic approach. We describe a 39-year-old woman with MCTD and clinical features of systemic sclerosis, presenting with Raynaud's phenomenon, digital ischemic ulcers, esophageal involvement, and pulmonary arterial hypertension. Her disease course was complicated by progressive cytopenia, including leukopenia, severe lymphopenia, mild anemia, and thrombocytopenia. Azathioprine therapy led to worsening pancytopenia, necessitating discontinuation, while glucocorticoids provided only partial hematologic recovery. Subsequent treatment with mycophenolate was ineffective. Introduction of anifrolumab (300 mg IV every 4 weeks) resulted in hematologic improvement, with normalization of hemoglobin and stabilization of leukocyte and platelet counts, without infusion-related adverse events. The findings support type I IFN blockade as a promising therapeutic avenue in refractory hematologic manifestations of connective tissue disease, warranting further investigation in larger studies.

PMID 42657973
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PubMedJournal of clinical medicine2026-08-27

Neutropenia and Lymphopenia in Systemic Lupus Erythematosus: Distinct Phenotypes and Associated Factors in a Saudi Multicenter Study.

Aljohani Roaa R, Aljanobi Ghada G, Alghanim Khawla K KK, Butt Nadeem N et al.

Background/Objectives: Neutropenia and lymphopenia are common hematologic manifestations of systemic lupus erythematosus (SLE), but whether they represent distinct phenotypes is not well established. This study evaluated their prevalence, patterns, and associated factors. Methods: This multicenter retrospective study included 353 adults with SLE from three Saudi centers. Cytopenias were defined using prespecified laboratory criteria. Patients were classified as having neither abnormality, isolated neutropenia, isolated lymphopenia, or both. Multivariable logistic regression was used to assess factors associated with ever-neutropenia and ever-lymphopenia. Results: Leukopenia occurred in 141 patients (39.9%). Ever-neutropenia and ever-lymphopenia were each observed in 88 patients (24.9%); 47 (13.3%) had isolated neutropenia, 47 (13.3%) had isolated lymphopenia, and 41 (11.6%) had both abnormalities. Persistent neutropenia and lymphopenia occurred in 22 (6.2%) and 23 (6.5%) patients, respectively. Most neutropenia was mild, and only three patients had severe neutropenia. The four phenotypes differed in age, body mass index, autoimmune hemolytic anemia, platelet count, anti-Smith positivity, and immunosuppressive exposure. No included variable was independently associated with ever-neutropenia. Ever-lymphopenia was independently associated with male sex (aOR 2.66, 95% CI 1.22-5.81), anti-Smith positivity (aOR 2.71, 95% CI 1.40-5.24), and exposure to azathioprine (aOR 2.07, 95% CI 1.16-3.71), mycophenolate mofetil use (aOR 2.79, 95% CI 1.42-5.52), and rituximab use (aOR 3.83, 95% CI 1.50-9.75). Conclusions: Neutropenia and lymphopenia each occurred in one-quarter of patients with SLE, whereas persistent cytopenias were uncommon. No independent associations were identified for ever-neutropenia. The demographic, serologic, and treatment-related associations of ever-lymphopenia support separate evaluation of the two abnormalities in SLE.

PMID 42652884
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