Table 3.

Drugs for the treatment of CD

Drug	Azathioprine (6-mercaptopurine)
Dosage	2-2.5 mg/kg (1-1.5 mg/kg)
Indications	Maintenance, chronically active disease, steroid- refractory and steroid-dependency, fistulae, concommittant therapy with infliximab;
Important side effects	Pancreatitis, bone marrow supression, allergic reactions, drug heptatitis, nausea, malaise, bacterial and viral infections; in patients intolerant to azathioprine due to gastrointestinal symptoms, 6-mercaptopurine is suggested (not in side effects such as pancreatitis and bone marrow suppression)
Monitoring	Liver function, lipase and full blood count biweekly for the first three months, if normal then every three months throughout therapy
Pregnancy	Should be avoided, although available studies suggest a potential use especially in patients where maintaining remission is essential
Comments	Entire therapeutic efficacy is observed mostly after 2-4 mo; consider testing for thiopurine methyltransferase (TPMT) genotypes to identify patients with high-risk of bone marrow suppression; consider metabolite monitoring for adaequate dosing; ensure adequate birth control; allow 3 mo time before pregnancy or conceiving