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

Summary:

Drug interactions are reported among people who take Benadryl (diphenhydramine hydrochloride) and Finacea (azelaic acid). Common drug interactions include sick sinus syndrome among females and hyponatraemia among males.

The phase IV clinical study analyzes what interactions people have when they take Benadryl and Finacea. It is created by eHealthMe based on reports of 34 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 104,955 Benadryl users. Check the latest studies of Benadryl.

What is Finacea?

Finacea has active ingredients of azelaic acid. It is often used in rosacea. eHealthMe is studying from 2,097 Finacea users. Check the latest studies of Finacea.

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, 26, 2026

34 people who take Benadryl and Finacea together, and have interactions are studied.

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

female:

Sick sinus syndrome (a collection of heart rhythm disorders)
Speech disorder
Syncope (loss of consciousness with an inability to maintain postural tone)
Temperature intolerance (inability to go in temperature)
Tooth infection
Trigger finger
Upper respiratory tract infection
Urinary hesitation (difficulty in beginning the flow of urine)
Sinusitis (inflammation of sinus)
Arthralgia (joint pain)

male:

Hyponatraemia (abnormally low level of sodium in the blood; associated with dehydration)
Urinary tract infection
Rash erythematous (redness of the skin)
Temperature intolerance (inability to go in temperature)
Urinary incontinence (inability to control the flow of urine and involuntary urination)
Anaemia (lack of blood)
Confusional state
Contusion (a type of hematoma of tissue in which capillaries)
Fatigue (feeling of tiredness)
Hypomagnesaemia (electrolyte disturbance in which there is an abnormally low level of magnesium in the blood)

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

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Abdominal discomfort
Abdominal pain upper
Hunger
Nausea (feeling of having an urge to vomit)

30-39:

Application site discolouration
Application site erythema (redness of the skin at application site)
Application site pain

40-49:

Infection
Nasopharyngitis (inflammation of the nasopharynx)
Osteomyelitis (infection of bone)
Pharyngitis (inflammation of the pharynx, causing a sore throat)
Sinusitis (inflammation of sinus)
Tooth infection
Body temperature increased
Chest discomfort
Cough
Dizziness

50-59:

Drug hypersensitivity
Drug ineffective
Gastric disorder (disease of stomach)
Muscle spasms (muscle contraction)
Psoriatic arthropathy (inflammation of the skin and joints with kin condition which typically causes patches (plaques) of red, scaly skin to develop)
Surgery
Fluid retention (an abnormal accumulation of fluid in the blood)
Pain
Temperature intolerance (inability to go in temperature)
Abdominal distension

60+:

Arthralgia (joint pain)
Fatigue (feeling of tiredness)
Multiple allergies (allergy to multiple agents)
Scar
Sinusitis (inflammation of sinus)
Sneezing
Weight decreased
Rash erythematous (redness of the skin)
Blood pressure increased
Polyarthritis (arthritis which involves 5 or more joints simultaneously)

What are the existing conditions these people have? *

Immunodeficiency Common Variable: 11 people, 32.35%
Primary Immunodeficiency Syndrome: 7 people, 20.59%
Narcolepsy (brain's inability to regulate sleep-wake cycles normally): 6 people, 17.65%
Nausea (feeling of having an urge to vomit): 4 people, 11.76%
Insomnia (sleeplessness): 4 people, 11.76%
High Blood Pressure: 4 people, 11.76%
Acne (skin problems that cause pimples): 3 people, 8.82%
Pain: 3 people, 8.82%
Constipation: 3 people, 8.82%
Depression: 2 people, 5.88%

* Approximation only. Some reports may have incomplete information.

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