Complete Allergy Relief Side Effects
Generic name: diphenhydramine
Note: This document contains side effect information about diphenhydramine. Some of the dosage forms listed on this page may not apply to the brand name Complete Allergy Relief.
Some side effects of Complete Allergy Relief may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to diphenhydramine: oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating
Stop taking diphenhydramine (the active ingredient contained in Complete Allergy Relief) and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).
Other, less serious side effects may be more likely to occur. Continue to take diphenhydramine and talk to your doctor if you experience
sleepiness, fatigue, or dizziness;
dry mouth; or
difficulty urinating or an enlarged prostate.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating
Nervous system side effects have been reported frequently. These have included depression with drowsiness and sedation in nearly all patients treated. Motor skills may be impaired. Dystonic reactions have been reported after single doses of diphenhydramine (the active ingredient contained in Complete Allergy Relief)
The CNS depressant effect of diphenhydramine parallels its plasma concentrations. The plasma concentration threshold for sedation is 30 to 42 ng/mL, and to cause mental impairment is 58 to 74 ng/mL. Patients should be warned against driving while taking diphenhydramine.
Dystonic reactions have been accompanied by dizziness, mental confusion, rigidity, lip and tongue protrusion, trismus, torticollis, and swallowing difficulties and generally resolve spontaneously. Toxic encephalopathy has been reported in a child with chicken pox treated generously with topical diphenhydramine.
Delirium has been reported in elderly patients with mild dementia following a small oral dose of diphenhydramine.
Hypersensitivity side effects have included rash, pruritus and eczema. Photosensitivity reactions have also been reported.
Most commonly, hypersensitivity has manifested itself in patients receiving systemic drug after being sensitized to it by topical application. Sensitization with systemic administration has also been reported.
Gastrointestinal side effects have been usually mild and included nausea and dry mouth.
Cardiovascular side effects have included hypotension, tachycardia, and palpitations.
Ocular side effects have included blurred vision, diplopia, and dry eyes due to anticholinergic effects.
Genitourinary side effects have included urinary retention and dysuria as a result of the anticholinergic effects of diphenhydramine (the active ingredient contained in Complete Allergy Relief)
Hematologic side effects such as hemolytic anemia, thrombocytopenia, and agranulocytosis have been rarely caused by antihistamines.