Xifaxan and Welchol drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Xifaxan (rifaximin) and Welchol (colesevelam hydrochloride). Common drug interactions include chronic kidney disease among females and constipation among males.

The phase IV clinical study analyzes what interactions people have when they take Xifaxan and Welchol. It is created by eHealthMe based on reports of 35 people who take the same drugs from the FDA, and is updated regularly.

What is Xifaxan?

Xifaxan has active ingredients of rifaximin. It is often used in irritable bowel syndrome. eHealthMe is studying from 16,609 Xifaxan users. Check the latest studies of Xifaxan.

What is Welchol?

Welchol has active ingredients of colesevelam hydrochloride. It is often used in high blood cholesterol. eHealthMe is studying from 11,309 Welchol users. Check the latest studies of Welchol.

eHealthMe: drug outcomes in the real world

eHealthMe runs one of the largest post-marketing drug safety studies in the world. We study millions of patients and 5,000 more each day. Our data-driven phase IV clinical trials have been referenced on 800+ peer-reviewed medical publications including The Lancet, Mayo Clinic Proceedings, and Nature. Tools to study our phase IV findings are available to the public, anonymous and free >>>.

On Aug, 15, 2026

35 people who take Xifaxan and Welchol together, and have interactions are studied.

What are the common drug interactions of Xifaxan and Welchol, by gender? *:

female:

Chronic kidney disease
Renal failure (kidney dysfunction)
Renal impairment (severely reduced kidney function)
Metabolic acidosis (body produces too much acid, or when the kidneys are not removing enough acid from the body)
Renal injury (kidney injury)
Abdominal discomfort
Abdominal pain upper
Anxiety
Arthralgia (joint pain)
Atrial fibrillation (fibrillation of the muscles of the atria of the heart)

male:

Constipation
Oedema peripheral (superficial swelling)
Neuropathy peripheral (surface nerve damage)
Polyp
Proctalgia (pain in the rectum)
Weight decreased
Bradycardia (abnormally slow heart action)
Chest discomfort
Epstein-barr virus infection
Hypersensitivity

What are the common drug interactions of Xifaxan and Welchol, by age (0-1 to 60+)? *:

0-1:

n/a

2-9:

n/a

10-19:

Bradycardia (abnormally slow heart action)
Chest discomfort
Epstein-barr virus infection
Hypersensitivity
Intra-abdominal haematoma (intra-abdominal localized swelling filled with blood)
Kidney transplant rejection
Respiratory arrest (cessation of normal respiration due to failure of the lungs to function effectively)
Thrombosis (formation of a blood clot inside a blood vessel)

20-29:

n/a

30-39:

Abdominal pain upper
Anxiety
Blood pressure increased
Crohn's disease (a condition that causes inflammation of the gastrointestinal tract)
Jaundice (a yellowish pigmentation of the skin, the conjunctival membranes)
Loss of consciousness
Memory impairment
Pain
Pruritus (severe itching of the skin)
Tremor (trembling or shaking movements in one or more parts of your body)

40-49:

Anal fistula
Anxiety
Constipation
Depression
Diverticulitis (digestive disease which involves the formation of pouches (diverticula) within the bowel wall)
Diverticulum (out pouching of a hollow (or a fluid-filled) structure in the body)
Eosinophilic oesophagitis (allergic inflammatory condition of the oesophagus)
Gastrooesophageal reflux disease (stomach contents (food or liquid) leak backwards from the stomach into the oesophagus)
Haemorrhoids (a swollen vein or group of veins in the region of the anus)
Oral candidiasis (fungal infection of mouth)

50-59:

Chronic kidney disease
Herpes zoster
Infection
Metabolic acidosis (body produces too much acid, or when the kidneys are not removing enough acid from the body)
White blood cell count decreased

60+:

Chronic kidney disease
Renal failure (kidney dysfunction)
Chronic obstructive pulmonary disease (a progressive disease that makes it hard to breathe)
Constipation
Gastric ulcer (stomach ulcer)
Hypotension (abnormally low blood pressure)
Impaired gastric emptying
Incontinence (lack of moderation or self-control)
Metabolic acidosis (body produces too much acid, or when the kidneys are not removing enough acid from the body)
Muscle injury

What are the existing conditions these people have? *

High Blood Pressure: 17 people, 48.57%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 15 people, 42.86%
Asthma: 12 people, 34.29%
Nausea (feeling of having an urge to vomit): 12 people, 34.29%
Diarrhea: 11 people, 31.43%
Pain: 11 people, 31.43%
Fluid Retention (an abnormal accumulation of fluid in the blood): 11 people, 31.43%
Infection: 10 people, 28.57%
Depression: 10 people, 28.57%
Hypothyroidism (abnormally low activity of the thyroid gland, resulting in retardation of growth and mental development): 10 people, 28.57%

* Approximation only. Some reports may have incomplete information.

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