Benadryl and Methylin drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Benadryl (diphenhydramine hydrochloride) and Methylin (methylphenidate hydrochloride). Common drug interactions include malaise among females and arrhythmia among males.

The phase IV clinical study analyzes what interactions people have when they take Benadryl and Methylin. It is created by eHealthMe based on reports of 15 people who take the same drugs from the FDA, and is updated regularly.

What is Benadryl?

Benadryl has active ingredients of diphenhydramine hydrochloride. It is often used in allergies. eHealthMe is studying from 104,954 Benadryl users. Check the latest studies of Benadryl.

What is Methylin?

Methylin has active ingredients of methylphenidate hydrochloride. It is often used in attention deficit hyperactivity disorder. eHealthMe is studying from 1,116 Methylin users. Check the latest studies of Methylin.

On Jul, 12, 2026

15 people who take Benadryl and Methylin together, and have interactions are studied.

Benadryl and Methylin drug interactions.

What are the common drug interactions of Benadryl and Methylin, by gender? *:

female:

Malaise (a feeling of general discomfort or uneasiness)
Pancreatitis acute (sudden inflammation of pancreas)
Back pain
Carpal tunnel syndrome (nerve compression at wrist results numbness weakness, pain , swelling)
Compulsions (performing an act persistently and repetitively)
Depression
Diarrhoea
Fall
Fatigue (feeling of tiredness)
Fluid retention (an abnormal accumulation of fluid in the blood)

male:

Arrhythmia (irregular heartbeat)
Upper gastrointestinal haemorrhage (upper gastrointestinal bleeding)
Sleep apnoea syndrome (a sleep-related disorder in which the effort to breathe is diminished or absent)
Urinary tract infection
Abdominal discomfort
Autism spectrum disorder (developmental disabilities that can cause significant social, communication and behavioural challenges)
Foetal exposure during pregnancy (exposing your unborn child to contraindicated in pregnancy leads birth defect)
Food allergy
Muscle spasms (muscle contraction)
Nasal septum deviation (deviated nasal septum)

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

0-1:

n/a

2-9:

Autism spectrum disorder (developmental disabilities that can cause significant social, communication and behavioural challenges)
Foetal exposure during pregnancy (exposing your unborn child to contraindicated in pregnancy leads birth defect)

10-19:

n/a

20-29:

n/a

30-39:

n/a

40-49:

Urinary tract infection
Pancreatitis acute (sudden inflammation of pancreas)
Muscle spasms (muscle contraction)
Osteoarthritis (a joint disease caused by cartilage loss in a joint)
Pneumonia

50-59:

Sleep apnoea syndrome (a sleep-related disorder in which the effort to breathe is diminished or absent)

60+:

Back pain
Diarrhoea
Fatigue (feeling of tiredness)
Malaise (a feeling of general discomfort or uneasiness)
Oral fungal infection

What are the existing conditions these people have? *

Narcolepsy (brain's inability to regulate sleep-wake cycles normally): 7 people, 46.67%
Cataplexy (loss of muscle tone accompanied by full conscious awareness): 4 people, 26.67%
Thyroid Cancer Metastatic (thyroid cancer spreads to other part): 3 people, 20.00%
Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 3 people, 20.00%
Sinusitis (inflammation of sinus): 1 person, 6.67%
Pancreatic Carcinoma (pancreatic cancer): 1 person, 6.67%
Infection: 1 person, 6.67%
Back Pain: 1 person, 6.67%
Autism Spectrum Disorder (developmental disabilities that can cause significant social, communication and behavioural challenges): 1 person, 6.67%

* Approximation only. Some reports may have incomplete information.

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