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Medications Linked to Ulcerative Colitis: Risks & Care

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that develops from a mix of genetic, immune, and environmental factors.

While no single medicine "causes" UC in everyone, some drugs are associated with a higher chance of triggering colitis-like inflammation or flares in people who are susceptible.

Can medications cause ulcerative colitis?

Strictly speaking, UC doesn’t have one known cause, and many people take the drugs below without ever developing UC. However, certain medications can irritate the gut lining, shift the microbiome, or stimulate the immune system in ways that may unmask UC in at-risk individuals or worsen existing disease. Researchers and clinicians therefore talk about medications “linked to UC” rather than proven universal causes. For background on UC, see the NIDDK overview and the Crohn’s & Colitis Foundation.

If you think a prescription or over-the-counter drug is affecting your gut, don’t stop it on your own—some medicines require tapering and may be essential for other conditions. Instead, talk to your prescriber about risks, alternatives, and whether to involve a gastroenterologist.

5 medications (or classes) linked to UC onset or flares

  1. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen. These can increase intestinal permeability and may be associated with UC flares. Many gastroenterology societies advise minimizing or avoiding routine NSAID use in IBD; consider acetaminophen for pain when appropriate. See the American College of Gastroenterology’s patient page on ulcerative colitis for safety tips.
  2. Broad-spectrum antibiotics (for example, clindamycin, fluoroquinolones, or repeated courses). Antibiotics can disrupt the gut microbiome; several population studies have linked cumulative antibiotic exposure with increased IBD risk. One large analysis is summarized on PubMed. Antibiotics can also precipitate Clostridioides difficile infection, which mimics or worsens UC; learn more at the CDC.
  3. Isotretinoin (formerly Accutane) for severe acne. Research is mixed: some studies found no overall increased IBD risk, while others suggest a small signal in certain groups. A 2013 meta-analysis in JAMA Dermatology found no significant association overall. If you develop new, persistent diarrhea or rectal bleeding while on isotretinoin, contact your doctor promptly.
  4. Estrogen-containing oral contraceptives or hormone therapy. Observational studies have reported a modest association between long-term use and IBD. A BMJ analysis discussed this potential link (BMJ). The absolute risk is still low, and contraceptive choices should weigh overall benefits and alternatives with your clinician.
  5. Immune checkpoint inhibitors (e.g., ipilimumab, nivolumab, pembrolizumab) used in cancer therapy. These can cause immune-mediated colitis that closely resembles UC and may require steroids or biologics to manage. See the National Cancer Institute’s summary of immunotherapy side effects.

How to recognize the signs of ulcerative colitis

Common symptoms include:

  • Frequent, urgent bowel movements
  • Diarrhea, often with blood or mucus
  • Cramping or abdominal pain
  • Fatigue, anemia, or unintentional weight loss
  • Fever during flares; nighttime stools

These symptoms overlap with infections, hemorrhoids, irritable bowel syndrome, and medication side effects. A clinician can help sort this out; see symptom overviews at MedlinePlus.

When to see a doctor (and when to seek urgent care)

  • New or persistent diarrhea lasting more than a few days, especially with blood
  • Severe abdominal pain, fever, dizziness, or signs of dehydration
  • Symptoms that begin soon after starting one of the medications above
  • Multiple nighttime stools, or inability to keep up with fluids
  • Known UC with rapidly worsening symptoms or failure of home measures

If you have heavy rectal bleeding, severe weakness, or signs of shock, seek emergency care immediately.

How UC is diagnosed

There’s no single test. Doctors combine your history, bloodwork, stool tests (including C. difficile), imaging, and colonoscopy with biopsies. Fecal calprotectin, a stool marker of intestinal inflammation, often helps distinguish IBD from IBS; see NICE guidance on fecal calprotectin. Learn more about the diagnostic process from the Crohn’s & Colitis Foundation: How UC is diagnosed.

Treatment options for ulcerative colitis

Your care team will tailor therapy to disease location and severity, other health conditions, and your preferences. Common options include:

  • 5-ASA (mesalamine) therapies in oral, enema, or suppository forms for mild to moderate disease.
  • Corticosteroids for short-term control of flares (not for long-term maintenance due to side effects).
  • Immunomodulators such as azathioprine or 6-mercaptopurine for steroid-sparing maintenance in select cases.
  • Biologics including anti-TNF agents (infliximab, adalimumab), anti-integrin (vedolizumab), and anti–IL-12/23 (ustekinumab).
  • Small molecules such as JAK inhibitors (tofacitinib, upadacitinib) and S1P modulators (ozanimod).
  • Surgery (colectomy) for severe, refractory disease or dysplasia; surgery can be curative for colitis but has lifelong considerations.

See overviews of UC treatments at the Crohn’s & Colitis Foundation and a list of approved medicines on the FDA. Long-term care also includes vaccinations, bone health, nutrition support, and mental health care. After 8–10 years of extensive colitis, you’ll also discuss colorectal cancer surveillance; learn more about risk and screening from the Foundation’s page on colorectal cancer.

How to find the right treatment if you’re diagnosed

Partner with the right team

Ask for referral to a gastroenterologist with IBD expertise, or an IBD center. Bring a medication list and your goals (symptom relief, steroid-free remission, fertility plans, travel, etc.). Don’t hesitate to seek a second opinion for complex decisions.

Use a treat-to-target plan

Modern IBD care often follows a treat-to-target strategy, aiming for symptom control and objective healing (normal labs, fecal calprotectin, and mucosal healing on colonoscopy). See the STRIDE-II recommendations summary on PubMed.

Address access and support

Ask about biosimilars and patient assistance if cost is a barrier. The Foundation lists financial resources. Track symptoms, stools, and side effects in a diary or app to share at visits.

Other factors that may contribute to UC risk or flares

  • Genetics and family history. Learn about IBD genetics from the NIH: Genome.gov.
  • Microbiome shifts and infections. C. difficile can both mimic and worsen UC; see the CDC.
  • Smoking status. Unlike Crohn’s disease, active smoking may transiently reduce UC activity but harms overall health; quitting can change disease course—discuss with your clinician. Review data in this open-access review.
  • Diet and stress. Neither directly “causes” UC, but both can influence symptoms and quality of life. See practical tips on diet and nutrition.

If you’re taking a suspect medication right now

  • Don’t stop abruptly. Call the prescriber who started the medicine to discuss your symptoms and options.
  • Ask about alternatives. For pain, acetaminophen may be safer than NSAIDs for many with IBD. For acne, dermatologists have multiple non-isotretinoin options. For contraception, discuss progestin-only or nonhormonal choices if appropriate.
  • Document your course. Note start dates, doses, and symptom timelines; bring photos if bleeding is hard to quantify.
  • Get evaluated. Your clinician may order stool tests (including pathogens), blood tests, and, if needed, colonoscopy to clarify the diagnosis.

This article is for education and does not replace personalized medical advice. If you suspect medication-related colitis or symptoms of UC, consult a qualified healthcare professional.