IBD, in full.

Before starting a biologic or immunomodulator in IBD or rheumatology patients, complete prestart safety screening: TB screening (IGRA preferred, treat latent TB before starting), hepatitis B (HBsAg/HBcAb/HBsAb with drug-class risk-stratified antiviral prophylaxis or monitoring), hepatitis C, HIV, Strongyloides serology for endemic-region patients, vaccination review with live vaccines given before starting, and baseline labs. Delay initiation for active infection, active/untreated TB, untreated HBV, or near-term pregnancy plans for JAK/methotrexate/ozanimod. Active or prior malignancy is not a blanket reason to delay therapy: the decision requires cancer- and drug-specific assessment (cancer type, stage, prognosis, and treatment status weighed against the specific agent) made jointly with oncology in a multidisciplinary setting, not a universal hold, when IBD activity needs control most therapies can be continued or initiated (gut-selective vedolizumab has the most reassuring cancer-recurrence data), thiopurines are preferably withdrawn in patients with active cancer, and a fixed (e.g., 5-year) delay before restarting therapy after cancer is no longer recommended.

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing. Treat mild-moderate disease with 5-ASA by route and extent (suppository for proctitis, enema for left-sided, oral plus rectal for extensive); if 5-ASA fails, treat as moderate-to-severe rather than stepping up gradually. Position advanced therapy by EFFICACY TIER, not by an anti-TNF-first rule. Advanced-therapy-naive, higher efficacy: infliximab, vedolizumab, ozanimod, etrasimod, upadacitinib, risankizumab, guselkumab; intermediate: golimumab, ustekinumab, tofacitinib, filgotinib, mirikizumab; lower: adalimumab. PREVIOUSLY TNF-EXPOSED, higher efficacy: tofacitinib, upadacitinib, ustekinumab; lower: adalimumab, vedolizumab, ozanimod, etrasimod - S1P modulators are weakest in exactly this group. Do not cycle within the anti-TNF class after primary non-response; switch mechanism. Apply treat-to-target (STRIDE-II) to endoscopic improvement (MES 0-1). Screen for acute severe UC by Truelove-Witts and admit for IV steroids. Begin CRC surveillance 8-10 years after DIAGNOSIS for extensive or left-sided disease; isolated proctitis follows average-risk screening.

DIAGNOSIS: Use fecal calprotectin (cutoff >50-100 μg/g) to differentiate inflammatory from noninflammatory disease OF THE COLON (strong, moderate). Ileocolonoscopy with biopsies for suspected CD; biopsy uninvolved mucosa to define histologic extent; small bowel imaging is part of the initial workup (key concepts, ungraded). CT enterography is comparable to MR enterography for small bowel detection; MRE should be used PREFERENTIALLY in patients younger than 35 years and where serial examinations are likely, because of radiation avoidance, MRE is not a blanket first choice. Intestinal ultrasound is a radiation-free ADJUNCT to diagnosis and to monitoring treatment response (key concept, ungraded, not a graded recommendation). Perform routine endoscopic CRC surveillance in Crohn's colitis (strong, moderate). MILD-TO-MODERATE / LOWER PROGRESSION RISK: Recommend AGAINST oral mesalamine for induction or maintenance (strong, moderate); sulfasalazine should be considered ONLY for symptomatic mild COLONIC CD (key concept). Controlled ileal-release budesonide 9 mg daily for induction of symptomatic remission in mildly-to-moderately active ileocecal CD (strong, moderate), but recommend AGAINST ileal-release budesonide for MAINTENANCE (strong, low). MODERATE-TO-SEVERE / HIGHER RISK: SUGGEST AGAINST requiring failure of conventional therapy before initiating advanced therapy (conditional, LOW, a permission to skip step-up, not a mandate to start advanced therapy upfront). Oral corticosteroids for short-term induction only (strong, low). Recommend AGAINST azathioprine 1.5-2.5 mg/kg/d and 6-mercaptopurine 0.75-1.5 mg/kg/d for INDUCTION (strong, moderate), but SUGGEST the same agents and doses for MAINTENANCE after corticosteroid-induced remission (conditional, low). Check TPMT before starting azathioprine/6-MP (strong, low); measure NUDT15 variants in patients of East Asian ancestry and TPMT variants in all patients prior to thiopurine initiation (strong, moderate). Methotrexate up to 25 mg weekly IM/SC for maintenance after corticosteroid induction (conditional, low). Anti-TNF agents (IV infliximab, SC adalimumab, SC certolizumab pegol) for induction and maintenance (strong, moderate). Recommend COMBINATION IV infliximab + thiopurine over either agent alone in patients naive to both (strong, moderate). Vedolizumab IV for induction and maintenance of symptomatic remission (strong, moderate). Ustekinumab (strong, moderate); risankizumab (strong, moderate), and risankizumab over ustekinumab in prior anti-TNF exposure (conditional, low); mirikizumab (strong, moderate); guselkumab IV-then-SC or all-SC (strong, moderate). Upadacitinib for induction and maintenance in patients PREVIOUSLY EXPOSED TO ANTI-TNF (strong, moderate), the ACG does not endorse it as a first-line biologic-naive option. SC infliximab and SC vedolizumab are maintenance options in responders to IV induction (strong, moderate). PERIANAL FISTULIZING: infliximab for induction (strong, moderate); adalimumab (conditional, low); antibiotics added to infliximab or adalimumab (conditional, very low); vedolizumab, ustekinumab, upadacitinib each (conditional, VERY LOW). Drain perianal abscesses and place setons before escalating advanced therapy (key concept). POST-OPERATIVE: endoscopic assessment at 6-12 months after surgically induced remission over no monitoring (conditional, moderate); in LOW post-op recurrence risk, continued observation rather than immediate medical therapy (conditional, very low); imidazole antibiotics (metronidazole) 1-2 g/d after small intestinal resection (conditional, low); in HIGH-risk CD, anti-TNF to prevent endoscopic recurrence (STRONG, moderate) and vedolizumab (CONDITIONAL, low), these two are not co-equal. SURGERY/ABSCESS: intra-abdominal abscess >2 cm should be treated with antibiotics plus a drainage procedure, and immunosuppression HELD until drainage is achieved (conditional, low). DISEASE MODIFIERS: counsel active smokers to quit; use NSAIDs with caution; assess stress, depression and anxiety as part of comprehensive care (key concepts).

DIAGNOSIS: Use fecal calprotectin (cutoff >50-100 μg/g) to differentiate inflammatory from noninflammatory disease OF THE COLON (strong, moderate). Ileocolonoscopy with biopsies for suspected CD; biopsy uninvolved mucosa to define histologic extent; small bowel imaging is part of the initial workup (key concepts, ungraded). CT enterography is comparable to MR enterography for small bowel detection; MRE should be used PREFERENTIALLY in patients younger than 35 years and where serial examinations are likely, because of radiation avoidance, MRE is not a blanket first choice. Intestinal ultrasound is a radiation-free ADJUNCT to diagnosis and to monitoring treatment response (key concept, ungraded, not a graded recommendation). Perform routine endoscopic CRC surveillance in Crohn's colitis (strong, moderate). MILD-TO-MODERATE / LOWER PROGRESSION RISK: Recommend AGAINST oral mesalamine for induction or maintenance (strong, moderate); sulfasalazine should be considered ONLY for symptomatic mild COLONIC CD (key concept). Controlled ileal-release budesonide 9 mg daily for induction of symptomatic remission in mildly-to-moderately active ileocecal CD (strong, moderate), but recommend AGAINST ileal-release budesonide for MAINTENANCE (strong, low). MODERATE-TO-SEVERE / HIGHER RISK: SUGGEST AGAINST requiring failure of conventional therapy before initiating advanced therapy (conditional, LOW, a permission to skip step-up, not a mandate to start advanced therapy upfront). Oral corticosteroids for short-term induction only (strong, low). Recommend AGAINST azathioprine 1.5-2.5 mg/kg/d and 6-mercaptopurine 0.75-1.5 mg/kg/d for INDUCTION (strong, moderate), but SUGGEST the same agents and doses for MAINTENANCE after corticosteroid-induced remission (conditional, low). Check TPMT before starting azathioprine/6-MP (strong, low); measure NUDT15 variants in patients of East Asian ancestry and TPMT variants in all patients prior to thiopurine initiation (strong, moderate). Methotrexate up to 25 mg weekly IM/SC for maintenance after corticosteroid induction (conditional, low). Anti-TNF agents (IV infliximab, SC adalimumab, SC certolizumab pegol) for induction and maintenance (strong, moderate). Recommend COMBINATION IV infliximab + thiopurine over either agent alone in patients naive to both (strong, moderate). Vedolizumab IV for induction and maintenance of symptomatic remission (strong, moderate). Ustekinumab (strong, moderate); risankizumab (strong, moderate), and risankizumab over ustekinumab in prior anti-TNF exposure (conditional, low); mirikizumab (strong, moderate); guselkumab IV-then-SC or all-SC (strong, moderate). Upadacitinib for induction and maintenance in patients PREVIOUSLY EXPOSED TO ANTI-TNF (strong, moderate), the ACG does not endorse it as a first-line biologic-naive option. SC infliximab and SC vedolizumab are maintenance options in responders to IV induction (strong, moderate). PERIANAL FISTULIZING: infliximab for induction (strong, moderate); adalimumab (conditional, low); antibiotics added to infliximab or adalimumab (conditional, very low); vedolizumab, ustekinumab, upadacitinib each (conditional, VERY LOW). Drain perianal abscesses and place setons before escalating advanced therapy (key concept). POST-OPERATIVE: endoscopic assessment at 6-12 months after surgically induced remission over no monitoring (conditional, moderate); in LOW post-op recurrence risk, continued observation rather than immediate medical therapy (conditional, very low); imidazole antibiotics (metronidazole) 1-2 g/d after small intestinal resection (conditional, low); in HIGH-risk CD, anti-TNF to prevent endoscopic recurrence (STRONG, moderate) and vedolizumab (CONDITIONAL, low), these two are not co-equal. SURGERY/ABSCESS: intra-abdominal abscess >2 cm should be treated with antibiotics plus a drainage procedure, and immunosuppression HELD until drainage is achieved (conditional, low). DISEASE MODIFIERS: counsel active smokers to quit; use NSAIDs with caution; assess stress, depression and anxiety as part of comprehensive care (key concepts).

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing. Treat mild-moderate disease with 5-ASA by route and extent (suppository for proctitis, enema for left-sided, oral plus rectal for extensive); if 5-ASA fails, treat as moderate-to-severe rather than stepping up gradually. Position advanced therapy by EFFICACY TIER, not by an anti-TNF-first rule. Advanced-therapy-naive, higher efficacy: infliximab, vedolizumab, ozanimod, etrasimod, upadacitinib, risankizumab, guselkumab; intermediate: golimumab, ustekinumab, tofacitinib, filgotinib, mirikizumab; lower: adalimumab. PREVIOUSLY TNF-EXPOSED, higher efficacy: tofacitinib, upadacitinib, ustekinumab; lower: adalimumab, vedolizumab, ozanimod, etrasimod - S1P modulators are weakest in exactly this group. Do not cycle within the anti-TNF class after primary non-response; switch mechanism. Apply treat-to-target (STRIDE-II) to endoscopic improvement (MES 0-1). Screen for acute severe UC by Truelove-Witts and admit for IV steroids. Begin CRC surveillance 8-10 years after DIAGNOSIS for extensive or left-sided disease; isolated proctitis follows average-risk screening.

DIAGNOSIS: Use fecal calprotectin (cutoff >50-100 μg/g) to differentiate inflammatory from noninflammatory disease OF THE COLON (strong, moderate). Ileocolonoscopy with biopsies for suspected CD; biopsy uninvolved mucosa to define histologic extent; small bowel imaging is part of the initial workup (key concepts, ungraded). CT enterography is comparable to MR enterography for small bowel detection; MRE should be used PREFERENTIALLY in patients younger than 35 years and where serial examinations are likely, because of radiation avoidance, MRE is not a blanket first choice. Intestinal ultrasound is a radiation-free ADJUNCT to diagnosis and to monitoring treatment response (key concept, ungraded, not a graded recommendation). Perform routine endoscopic CRC surveillance in Crohn's colitis (strong, moderate). MILD-TO-MODERATE / LOWER PROGRESSION RISK: Recommend AGAINST oral mesalamine for induction or maintenance (strong, moderate); sulfasalazine should be considered ONLY for symptomatic mild COLONIC CD (key concept). Controlled ileal-release budesonide 9 mg daily for induction of symptomatic remission in mildly-to-moderately active ileocecal CD (strong, moderate), but recommend AGAINST ileal-release budesonide for MAINTENANCE (strong, low). MODERATE-TO-SEVERE / HIGHER RISK: SUGGEST AGAINST requiring failure of conventional therapy before initiating advanced therapy (conditional, LOW, a permission to skip step-up, not a mandate to start advanced therapy upfront). Oral corticosteroids for short-term induction only (strong, low). Recommend AGAINST azathioprine 1.5-2.5 mg/kg/d and 6-mercaptopurine 0.75-1.5 mg/kg/d for INDUCTION (strong, moderate), but SUGGEST the same agents and doses for MAINTENANCE after corticosteroid-induced remission (conditional, low). Check TPMT before starting azathioprine/6-MP (strong, low); measure NUDT15 variants in patients of East Asian ancestry and TPMT variants in all patients prior to thiopurine initiation (strong, moderate). Methotrexate up to 25 mg weekly IM/SC for maintenance after corticosteroid induction (conditional, low). Anti-TNF agents (IV infliximab, SC adalimumab, SC certolizumab pegol) for induction and maintenance (strong, moderate). Recommend COMBINATION IV infliximab + thiopurine over either agent alone in patients naive to both (strong, moderate). Vedolizumab IV for induction and maintenance of symptomatic remission (strong, moderate). Ustekinumab (strong, moderate); risankizumab (strong, moderate), and risankizumab over ustekinumab in prior anti-TNF exposure (conditional, low); mirikizumab (strong, moderate); guselkumab IV-then-SC or all-SC (strong, moderate). Upadacitinib for induction and maintenance in patients PREVIOUSLY EXPOSED TO ANTI-TNF (strong, moderate), the ACG does not endorse it as a first-line biologic-naive option. SC infliximab and SC vedolizumab are maintenance options in responders to IV induction (strong, moderate). PERIANAL FISTULIZING: infliximab for induction (strong, moderate); adalimumab (conditional, low); antibiotics added to infliximab or adalimumab (conditional, very low); vedolizumab, ustekinumab, upadacitinib each (conditional, VERY LOW). Drain perianal abscesses and place setons before escalating advanced therapy (key concept). POST-OPERATIVE: endoscopic assessment at 6-12 months after surgically induced remission over no monitoring (conditional, moderate); in LOW post-op recurrence risk, continued observation rather than immediate medical therapy (conditional, very low); imidazole antibiotics (metronidazole) 1-2 g/d after small intestinal resection (conditional, low); in HIGH-risk CD, anti-TNF to prevent endoscopic recurrence (STRONG, moderate) and vedolizumab (CONDITIONAL, low), these two are not co-equal. SURGERY/ABSCESS: intra-abdominal abscess >2 cm should be treated with antibiotics plus a drainage procedure, and immunosuppression HELD until drainage is achieved (conditional, low). DISEASE MODIFIERS: counsel active smokers to quit; use NSAIDs with caution; assess stress, depression and anxiety as part of comprehensive care (key concepts).

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing. Treat mild-moderate disease with 5-ASA by route and extent (suppository for proctitis, enema for left-sided, oral plus rectal for extensive); if 5-ASA fails, treat as moderate-to-severe rather than stepping up gradually. Position advanced therapy by EFFICACY TIER, not by an anti-TNF-first rule. Advanced-therapy-naive, higher efficacy: infliximab, vedolizumab, ozanimod, etrasimod, upadacitinib, risankizumab, guselkumab; intermediate: golimumab, ustekinumab, tofacitinib, filgotinib, mirikizumab; lower: adalimumab. PREVIOUSLY TNF-EXPOSED, higher efficacy: tofacitinib, upadacitinib, ustekinumab; lower: adalimumab, vedolizumab, ozanimod, etrasimod - S1P modulators are weakest in exactly this group. Do not cycle within the anti-TNF class after primary non-response; switch mechanism. Apply treat-to-target (STRIDE-II) to endoscopic improvement (MES 0-1). Screen for acute severe UC by Truelove-Witts and admit for IV steroids. Begin CRC surveillance 8-10 years after DIAGNOSIS for extensive or left-sided disease; isolated proctitis follows average-risk screening.

Perioperative management of a patient already taking a GLP-1 receptor agonist should be individualized through shared decision-making among the patient, the prescribing team, the proceduralist/surgeon, and the anesthesiologist, balancing metabolic need against aspiration risk from delayed gastric emptying. In patients WITHOUT known risk factors for delayed gastric emptying (e.g., pre-existing gastroparesis, diabetes mellitus with neuropathy, prior gastric surgery, or severe GERD), GLP-1RA therapy may be continued preoperatively. When holding is elected, hold the day-of-procedure dose for daily formulations and the dose one week before the procedure for weekly formulations, while acknowledging the guidance states the optimal hold duration is unknown. Regardless of hold status, assess every patient on the day of the procedure for symptoms of delayed gastric emptying (nausea, vomiting, abdominal pain, dyspepsia, distension); if present, manage the patient as a 'full stomach.' For patients WITH known risk factors for delayed gastric emptying, risk-mitigation options include a preoperative clear-liquid diet for at least 24 hours (as in colonoscopy/bariatric prep), point-of-care gastric ultrasound to assess residual gastric contents (limited by resources, inter-user variability, and credentialing), and consideration of rapid-sequence induction versus procedure deferral. The guidance explicitly cautions against reflexively withholding GLP-1RAs only in patients treated for overweight/obesity, which could constitute weight bias. The document does not address whether a GI condition warrants pre-initiation 'GI clearance' before starting a GLP-1RA; that question is not covered by this or any GI society guideline.

Confirm ulcerative colitis with endoscopy showing continuous colonic inflammation from the rectum plus histology, after excluding infection with two-step CDI testing. Treat mild-moderate disease with 5-ASA by route and extent (suppository for proctitis, enema for left-sided, oral plus rectal for extensive); if 5-ASA fails, treat as moderate-to-severe rather than stepping up gradually. Position advanced therapy by EFFICACY TIER, not by an anti-TNF-first rule. Advanced-therapy-naive, higher efficacy: infliximab, vedolizumab, ozanimod, etrasimod, upadacitinib, risankizumab, guselkumab; intermediate: golimumab, ustekinumab, tofacitinib, filgotinib, mirikizumab; lower: adalimumab. PREVIOUSLY TNF-EXPOSED, higher efficacy: tofacitinib, upadacitinib, ustekinumab; lower: adalimumab, vedolizumab, ozanimod, etrasimod - S1P modulators are weakest in exactly this group. Do not cycle within the anti-TNF class after primary non-response; switch mechanism. Apply treat-to-target (STRIDE-II) to endoscopic improvement (MES 0-1). Screen for acute severe UC by Truelove-Witts and admit for IV steroids. Begin CRC surveillance 8-10 years after DIAGNOSIS for extensive or left-sided disease; isolated proctitis follows average-risk screening.

DIAGNOSIS: Use fecal calprotectin (cutoff >50-100 μg/g) to differentiate inflammatory from noninflammatory disease OF THE COLON (strong, moderate). Ileocolonoscopy with biopsies for suspected CD; biopsy uninvolved mucosa to define histologic extent; small bowel imaging is part of the initial workup (key concepts, ungraded). CT enterography is comparable to MR enterography for small bowel detection; MRE should be used PREFERENTIALLY in patients younger than 35 years and where serial examinations are likely, because of radiation avoidance, MRE is not a blanket first choice. Intestinal ultrasound is a radiation-free ADJUNCT to diagnosis and to monitoring treatment response (key concept, ungraded, not a graded recommendation). Perform routine endoscopic CRC surveillance in Crohn's colitis (strong, moderate). MILD-TO-MODERATE / LOWER PROGRESSION RISK: Recommend AGAINST oral mesalamine for induction or maintenance (strong, moderate); sulfasalazine should be considered ONLY for symptomatic mild COLONIC CD (key concept). Controlled ileal-release budesonide 9 mg daily for induction of symptomatic remission in mildly-to-moderately active ileocecal CD (strong, moderate), but recommend AGAINST ileal-release budesonide for MAINTENANCE (strong, low). MODERATE-TO-SEVERE / HIGHER RISK: SUGGEST AGAINST requiring failure of conventional therapy before initiating advanced therapy (conditional, LOW, a permission to skip step-up, not a mandate to start advanced therapy upfront). Oral corticosteroids for short-term induction only (strong, low). Recommend AGAINST azathioprine 1.5-2.5 mg/kg/d and 6-mercaptopurine 0.75-1.5 mg/kg/d for INDUCTION (strong, moderate), but SUGGEST the same agents and doses for MAINTENANCE after corticosteroid-induced remission (conditional, low). Check TPMT before starting azathioprine/6-MP (strong, low); measure NUDT15 variants in patients of East Asian ancestry and TPMT variants in all patients prior to thiopurine initiation (strong, moderate). Methotrexate up to 25 mg weekly IM/SC for maintenance after corticosteroid induction (conditional, low). Anti-TNF agents (IV infliximab, SC adalimumab, SC certolizumab pegol) for induction and maintenance (strong, moderate). Recommend COMBINATION IV infliximab + thiopurine over either agent alone in patients naive to both (strong, moderate). Vedolizumab IV for induction and maintenance of symptomatic remission (strong, moderate). Ustekinumab (strong, moderate); risankizumab (strong, moderate), and risankizumab over ustekinumab in prior anti-TNF exposure (conditional, low); mirikizumab (strong, moderate); guselkumab IV-then-SC or all-SC (strong, moderate). Upadacitinib for induction and maintenance in patients PREVIOUSLY EXPOSED TO ANTI-TNF (strong, moderate), the ACG does not endorse it as a first-line biologic-naive option. SC infliximab and SC vedolizumab are maintenance options in responders to IV induction (strong, moderate). PERIANAL FISTULIZING: infliximab for induction (strong, moderate); adalimumab (conditional, low); antibiotics added to infliximab or adalimumab (conditional, very low); vedolizumab, ustekinumab, upadacitinib each (conditional, VERY LOW). Drain perianal abscesses and place setons before escalating advanced therapy (key concept). POST-OPERATIVE: endoscopic assessment at 6-12 months after surgically induced remission over no monitoring (conditional, moderate); in LOW post-op recurrence risk, continued observation rather than immediate medical therapy (conditional, very low); imidazole antibiotics (metronidazole) 1-2 g/d after small intestinal resection (conditional, low); in HIGH-risk CD, anti-TNF to prevent endoscopic recurrence (STRONG, moderate) and vedolizumab (CONDITIONAL, low), these two are not co-equal. SURGERY/ABSCESS: intra-abdominal abscess >2 cm should be treated with antibiotics plus a drainage procedure, and immunosuppression HELD until drainage is achieved (conditional, low). DISEASE MODIFIERS: counsel active smokers to quit; use NSAIDs with caution; assess stress, depression and anxiety as part of comprehensive care (key concepts).