Fentanyl-100 and Flexeril drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Fentanyl-100 (fentanyl) and Flexeril (cyclobenzaprine hydrochloride). Common drug interactions include bronchitis among females and drug ineffective among males.

The phase IV clinical study analyzes what interactions people have when they take Fentanyl-100 and Flexeril. It is created by eHealthMe based on reports of 98 people who take the same drugs from the FDA, and is updated regularly.

What is Fentanyl-100?

Fentanyl-100 has active ingredients of fentanyl. It is often used in pain. eHealthMe is studying from 7,047 Fentanyl-100 users. Check the latest studies of Fentanyl-100.

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.

On Jul, 14, 2026

98 people who take Fentanyl-100 and Flexeril together, and have interactions are studied.

Fentanyl-100 and Flexeril drug interactions.

What are the common drug interactions of Fentanyl-100 and Flexeril, by gender? *:

female:

Bronchitis (inflammation of the mucous membrane in the bronchial tubes)
Hypertension (high blood pressure)
Dry eye (lack of adequate tears)
Kidney infection
Hypoaesthesia (reduced sense of touch or sensation)
Somnolence (a state of near-sleep, a strong desire for sleep)
Weight increased
Application site rash
Fall
Anxiety

male:

Drug ineffective
Fall
Dyspnoea (difficult or laboured respiration)
Fatigue (feeling of tiredness)
Hypoaesthesia (reduced sense of touch or sensation)
Osteonecrosis of jaw (death of bone of jaw)
Withdrawal syndrome (a discontinuation syndrome is a set of symptoms occurred due to discontinuation of substance)
Dysuria (painful or difficult urination)
Nephrolithiasis (calculi in the kidneys)
Therapeutic response decreased (less preventive response)

What are the common drug interactions of Fentanyl-100 and Flexeril, by age (0-1 to 60+)? *:

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Fall
Abdominal discomfort
Formication (a sensation that exactly resembles that of small insects crawling on (or under) the skin)
Hypoaesthesia (reduced sense of touch or sensation)
Malaise (a feeling of general discomfort or uneasiness)
Neuropathy peripheral (surface nerve damage)
Peroneal nerve palsy
Sciatica (a set of symptoms including pain caused by general compression or irritation of one of five spinal nerve roots of each sciatic nerve)
Abnormal loss of weight
Anxiety

30-39:

Drug ineffective
Somnolence (a state of near-sleep, a strong desire for sleep)
Swelling
Deep vein thrombosis (blood clot in a major vein that usually develops in the legs and/or pelvis)
Hypoaesthesia (reduced sense of touch or sensation)
Pneumonitis (inflammation of the walls of the alveoli in the lungs)
Therapeutic response decreased (less preventive response)
Abasia (inability to walk)
Abdominal pain
Ankylosing spondylitis (type of arthritis affecting the spine)

40-49:

Osteoarthritis (a joint disease caused by cartilage loss in a joint)
Drug ineffective
Dyspnoea (difficult or laboured respiration)
Therapeutic response decreased (less preventive response)
Nausea (feeling of having an urge to vomit)
Pneumonia
Dyspepsia (indigestion)
Headache (pain in head)
Abdominal discomfort
Dizziness

50-59:

Bronchitis (inflammation of the mucous membrane in the bronchial tubes)
Hiatus hernia (hernia resulting from the protrusion of part of the stomach through the diaphragm)
Osteoarthritis (a joint disease caused by cartilage loss in a joint)
Pneumonia
Arthropathy
Diarrhoea
Hypertension (high blood pressure)
Mouth ulceration (mouth ulcers)
Nausea (feeling of having an urge to vomit)
Pain in jaw

60+:

Arthropathy
Dermatitis contact (skin reaction (dermatitis) resulting from exposure to allergens)
Restlessness (not able to rest)
Drug effect decreased
Amnesia (deficit in memory caused by brain damage, disease, or psychological trauma)
Asthenia (weakness)
Back disorder
Coma (state of unconsciousness lasting more than six hours)
Fall
Hepatitis acute

What are the existing conditions these people have? *

Back Pain: 26 people, 26.53%
Depression: 22 people, 22.45%
Breakthrough Pain: 21 people, 21.43%
High Blood Pressure: 17 people, 17.35%
Sleep Disorder: 16 people, 16.33%
Stress And Anxiety: 15 people, 15.31%
Neuralgia (pain in one or more nerves): 12 people, 12.24%
Nausea (feeling of having an urge to vomit): 11 people, 11.22%
Joint Pain: 9 people, 9.18%
High Blood Cholesterol: 8 people, 8.16%

* Approximation only. Some reports may have incomplete information.

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