Flexeril and Trimethoprim drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Flexeril (cyclobenzaprine hydrochloride) and Trimethoprim (trimethoprim). Common drug interactions include spinal decompression among females and diabetes mellitus among males.

The phase IV clinical study analyzes what interactions people have when they take Flexeril and Trimethoprim. It is created by eHealthMe based on reports of 37 people who take the same drugs from the FDA, and is updated regularly.

What is Flexeril?

Flexeril has active ingredients of cyclobenzaprine hydrochloride. It is often used in muscle spasms. eHealthMe is studying from 38,308 Flexeril users. Check the latest studies of Flexeril.

What is Trimethoprim?

Trimethoprim has active ingredients of trimethoprim. It is often used in urinary tract infection. eHealthMe is studying from 8,213 Trimethoprim users. Check the latest studies of Trimethoprim.

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, 22, 2026

37 people who take Flexeril and Trimethoprim together, and have interactions are studied.

Flexeril and Trimethoprim drug interactions.

What are the common drug interactions of Flexeril and Trimethoprim, by gender? *:

female:

Spinal decompression (relief of pressure on one or many pinched nerves (neural impingement) of the spinal column)
Tenosynovitis (inflammation of the fluid-filled sheath (called the synovium) that surrounds a tendon)
Tooth extraction
Abdominal pain
Blindness unilateral
Cough
Dyspnoea (difficult or laboured respiration)
Iritis (painful inflammation of the iris of the eye)
Pain in extremity
Proteinuria (presence of protein in the urine)

male:

Diabetes mellitus (diabetes, caused by a deficiency of the pancreatic hormone insulin)
Chest pain
Bursitis (inflammation of a bursa, typically one in the knee, elbow, or shoulder)
Cardiac failure congestive
Coronary artery disease (plaque building up along the inner walls of the arteries of the heart, which narrows the arteries and restricts blood flow to the heart)
Coronary artery occlusion (complete obstruction of blood flow in a coronary artery)
Depression
Diabetic retinopathy (damage to the retina caused by complications of diabetes)
Discomfort
Dyskinesia (abnormality or impairment of voluntary movement)

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

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Chronic kidney disease
Renal failure (kidney dysfunction)
Renal injury (kidney injury)

30-39:

Colitis ulcerative (inflammation of colon with ulcer)
Diabetes mellitus (diabetes, caused by a deficiency of the pancreatic hormone insulin)
Diabetic retinopathy (damage to the retina caused by complications of diabetes)
Dizziness
Fatigue (feeling of tiredness)
Hypoaesthesia (reduced sense of touch or sensation)
Malaise (a feeling of general discomfort or uneasiness)
Myalgia (muscle pain)
Paraesthesia (sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect)
Pyrexia (fever)

40-49:

Aggression
Bursitis (inflammation of a bursa, typically one in the knee, elbow, or shoulder)
Depression
Diabetes mellitus (diabetes, caused by a deficiency of the pancreatic hormone insulin)
Jaw fracture
Musculoskeletal pain (pain affects the bones, muscles, ligaments, tendons, and nerves)
Swelling face
Tendonitis (a condition that causes pain and swelling of tendons)

50-59:

Ischaemia (insufficient supply of blood to an organ, usually due to a blocked artery)
Lymphadenopathy (disease or enlargement of lymph nodes)
Metastases to liver (cancer spreads to liver)
Metastases to spine (cancer spreads to spine)
Muscular weakness (muscle weakness)
Myofascial pain syndrome (a painful condition that affects the muscles and the sheath of the tissue)
Neutropenia (an abnormally low number of neutrophils)
Osteoarthritis (a joint disease caused by cartilage loss in a joint)
Osteoporosis (bones weak and more likely to break)
Pain in jaw

60+:

Anxiety
Asthenia (weakness)
Escherichia infection (bacterial infection by escherichia coli)
Eye irritation
Hyperhidrosis (abnormally increased sweating)
Hypertension (high blood pressure)
Hypotension (abnormally low blood pressure)
Iritis (painful inflammation of the iris of the eye)
Malaise (a feeling of general discomfort or uneasiness)
Nausea (feeling of having an urge to vomit)

What are the existing conditions these people have? *

Neoplasm Malignant (cancer tumour): 10 people, 27.03%
Pain: 7 people, 18.92%
Stress And Anxiety: 6 people, 16.22%
Depression: 5 people, 13.51%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 5 people, 13.51%
High Blood Pressure: 4 people, 10.81%
Nausea (feeling of having an urge to vomit): 4 people, 10.81%
High Blood Cholesterol: 4 people, 10.81%
Osteoporosis (bones weak and more likely to break): 3 people, 8.11%
Infection: 3 people, 8.11%

* Approximation only. Some reports may have incomplete information.

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