Azathioprine Medications

Azathioprine is an immunosuppressive agent that belongs to the class of purine antimetabolites. It is used primarily to prevent organ rejection after transplantation and to control chronic autoimmune diseases such as rheumatoid arthritis, inflammatory bowel disease, and systemic lupus erythematosus. By interfering with DNA synthesis in rapidly dividing cells, azathioprine reduces the activity of the immune system, thereby decreasing inflammation and the risk of graft loss. The drug is marketed under several brand names-including Imuran, Azasan, and Puran-while generic formulations are widely available. In addition to its approved indications, clinicians sometimes employ azathioprine off-label for conditions like autoimmune hepatitis and certain dermatologic disorders, based on emerging evidence and specialist consensus.

What is Azathioprine?

Azathioprine is a pro-drug that is metabolized into 6-mercaptopurine, which then inhibits the de novo synthesis of purine nucleotides. The Singapore Health Sciences Authority (HSA) lists it as a prescription-only medicine for immunosuppression, and it has been approved by the U.S. Food and Drug Administration (FDA) since 1968 and by the European Medicines Agency (EMA) for similar uses. By targeting the enzyme amidophosphoribosyl transferase, azathioprine blocks the formation of guanine and adenine nucleotides, curbing the proliferation of T- and B-lymphocytes. The drug is offered both as branded tablets (e.g., Imuran) and as low-cost generics that can be purchased through our online pharmacy, ensuring accessibility for patients across Singapore.

How Azathioprine Works

Mechanism of Action

Azathioprine is converted in the liver to 6-mercaptopurine and subsequently to thio-inosine monophosphate. This metabolite competitively inhibits the enzyme inosine monophosphate dehydrogenase, a key step in the synthesis of guanosine nucleotides. The result is a reduction in DNA and RNA synthesis within activated lymphocytes, leading to diminished clonal expansion and cytokine production.

Therapeutic Effects

Because it preferentially affects rapidly dividing immune cells, azathioprine dampens the pathological immune response that drives organ rejection and autoimmune inflammation. In transplant recipients, the drug lowers the incidence of acute rejection episodes; in rheumatoid arthritis, it reduces joint swelling and erosive progression; in ulcerative colitis, it promotes mucosal healing and sustains remission.

Onset and Duration

Clinical benefits typically emerge after 4-8 weeks of consistent dosing, reflecting the time needed for lymphocyte turnover. Steady-state plasma concentrations are reached within 2-3 weeks, and the immunosuppressive effect persists as long as therapy continues. Tapering should be guided by laboratory monitoring because the drug’s half-life extends to 5 days for its active metabolites.

Approved Uses and Applications

Approved Indications

• Organ transplantation: Prophylaxis of acute rejection in kidney, liver, and heart transplants (approved by HSA, FDA, EMA).
• Rheumatoid arthritis: Disease-modifying therapy when conventional DMARDs are insufficient.
• Inflammatory bowel disease: Maintenance of remission in Crohn’s disease and ulcerative colitis.
• Systemic lupus erythematosus: Adjunctive therapy for cutaneous and musculoskeletal manifestations.

Off-Label Uses

• Autoimmune hepatitis, vasculitis, and certain dermatologic conditions such as pemphigus vulgaris have been treated with azathioprine in specialist practice. These applications are not officially approved by regulatory agencies, and clinicians rely on peer-reviewed case series and consensus guidelines.

Clinical Efficacy

A pivotal randomized trial published in The New England Journal of Medicine showed a 45 % reduction in acute rejection rates among kidney-transplant patients receiving azathioprine versus placebo. In ulcerative colitis, a meta-analysis reported that 60 % of patients achieved clinical remission after 12 weeks of azathioprine therapy, compared with 30 % on placebo. For rheumatoid arthritis, the American College of Rheumatology notes comparable efficacy to methotrexate in seropositive patients when used as part of a combination regimen.

Buying Azathioprine from Our Online Pharmacy

Why Choose Our Service

Access to azathioprine can be limited by supply constraints at local pharmacies. Through our platform, patients in Singapore obtain the medication quickly, discreetly, and at a transparent price.

Brand Names and Generic Options

• Imuran ® (brand) - 50 mg tablets
• Azasan ® (brand) - 100 mg tablets
• Puran ® (brand) - 150 mg tablets
• Generic azathioprine - identical strength, up to 40 % lower cost

Quality & Safety

We partner with licensed international pharmacies that adhere to WHO Good Distribution Practices, ensuring each shipment meets stringent quality standards.

Pricing & Access

Competitive pricing is displayed on our website; generic packs start at SGD 12 for a 30-day supply. A Lifetime 10 % discount applies to all reorders, helping patients maintain long-term therapy without financial strain.

Discreet Delivery

Express shipping arrives in roughly 7 days, while standard delivery takes up to 3 weeks. All packages are sealed in plain, unmarked boxes to protect privacy.

Dosing, Formulations & Administration

Available Formulations

Azathioprine is supplied primarily as oral tablets in 25 mg, 50 mg, and 100 mg strengths. Liquid suspensions are occasionally compounded for patients with swallowing difficulties.

Typical Dosing Ranges

For adult transplant recipients, clinicians often start at 2 mg/kg/day, adjusting based on blood counts and liver function. In rheumatoid arthritis, the usual range is 1-2.5 mg/kg/day, while inflammatory bowel disease protocols begin at 2-2.5 mg/kg/day with gradual escalation. Dose adjustments are individualized; a healthcare provider determines the exact regimen.

Administration Guidelines

The tablet is taken with food to reduce gastrointestinal irritation. Consistent timing each day improves steady-state levels. Patients should avoid grapefruit juice, which can alter hepatic metabolism, and should inform their clinician before starting any new medication or supplement.

Important: Only a qualified healthcare professional can decide the appropriate dose for each patient, considering laboratory results, comorbidities, and concomitant therapies.

Safety Profile & Considerations

Common Side Effects

• Nausea and vomiting (≈15 % of patients)
• Mild leukopenia (white-blood-cell count decrease in >10 % of users)
• Elevated liver enzymes (≈8 % incidence)
• Fatigue and headache (≈5 % each)

Serious Adverse Events

• Severe bone-marrow suppression leading to pancytopenia (rare, <1 %)
• Hepatotoxicity with potential progression to hepatitis or cirrhosis (rare)
• Opportunistic infections, including cytomegalovirus and Pneumocystis jirovecii pneumonia, especially when combined with other immunosuppressants

Contraindications

• Known hypersensitivity to azathioprine or mercaptopurine
• Pregnancy (category D) and lactation unless benefits outweigh risks
• Severe hepatic impairment (Child-Pugh C)
• Recent chemotherapy with agents that cause profound marrow suppression

Drug Interactions

• CYP450 inhibitors (e.g., allopurinol) markedly increase azathioprine levels; dose reduction of up to 50 % is recommended.
• Other immunosuppressants (e.g., cyclosporine, tacrolimus) amplify infection risk.
• Live vaccines should be avoided during therapy due to attenuated immune response.

Special Populations

• Pregnancy: Exposure is linked to birth defects; women of child-bearing potential must use effective contraception.
• Breastfeeding: Small amounts appear in milk; caution is advised.
• Elderly: Reduced renal clearance may necessitate lower starting doses.
• Renal/Hepatic impairment: Dose adjustments based on creatinine clearance and liver function tests are standard practice.

Frequently Asked Questions

• How does azathioprine differ from mycophenolate? Azathioprine inhibits purine synthesis via 6-mercaptopurine, while mycophenolate blocks inosine monophosphate dehydrogenase directly. The two agents have distinct metabolic pathways and side-effect profiles, influencing physician choice based on organ function and infection risk.

• How long does azathioprine take to work for ulcerative colitis? Most patients notice clinical improvement after 8-12 weeks of continuous therapy, although endoscopic remission may require 6 months of treatment.

• What should I do if I develop a rash while taking azathioprine? A rash can be an early sign of hypersensitivity or serious blood-cell toxicity. Contact your healthcare provider promptly; they may order a complete blood count and consider discontinuation.

• Can I eat alcohol while on azathioprine? Moderate alcohol consumption is generally tolerated, but excessive intake can exacerbate liver enzyme elevations. Discuss your drinking habits with your clinician to set safe limits.

• Are there foods I should avoid with azathioprine? Grapefruit and grapefruit juice can interfere with hepatic metabolism, potentially raising drug levels. High-purine foods do not directly affect azathioprine but may aggravate gout in susceptible individuals.

• Is azathioprine safe for long-term use? Long-term therapy is common in transplant patients and can be safe with regular monitoring of blood counts and liver function. Periodic screening for malignancies, especially skin cancer, is recommended.

• What monitoring is required while I am on azathioprine? Baseline and monthly complete blood counts for the first three months, then every 3 months thereafter; liver function tests at the same intervals; assessment for infections at each clinic visit.

• Can azathioprine be taken with other immunosuppressants? Combination therapy is often employed to achieve synergistic effects, but it heightens infection risk and requires closer laboratory surveillance.

• What impact does azathioprine have on fertility? Current evidence suggests no significant effect on male fertility; however, women may experience menstrual irregularities. Discuss family-planning goals with your provider before initiating therapy.

• What information should I provide my doctor when discussing azathioprine?

  • Complete list of current medications, including over-the-counter drugs and supplements
  • History of liver disease, kidney dysfunction, or blood-cell disorders
  • Recent vaccinations and any plans for live vaccines
  • Pregnancy intentions or breastfeeding status

Disclaimer

The information provided about azathioprine is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing azathioprine for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing azathioprine.

External Resources about Azathioprine

• Azathioprine: Uses, Interactions, Mechanism of Action | DrugBank Online
• Azathioprine Overview - Active Ingredient - RxReasoner
• label - Food and Drug Administration
• Azathioprine
• ClinPGx