Diphenhydramine and pseudoephedrine

Diphenhydramine is an antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Pseudoephedrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Diphenhydramine and pseudoephedrine is a combination medicine used to treat sneezing, cough, runny or stuffy nose, itchy or watery eyes, hives, skin rash, itching, and other symptoms of allergies and the common cold.

Diphenhydramine and pseudoephedrine may also be used for purposes not listed in this medication guide.

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

You should not use antihistamine medication to make a child sleepy.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Call your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.

If you need surgery, tell the surgeon ahead of time if you have taken a cold medicine within the past few days.

This medication can cause unusual results with allergy skin tests. Tell any doctor who treats you that you are taking an antihistamine.

Store the medication at room temperature away from moisture and heat.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking diphenhydramine and pseudoephedrine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Dizziness.
• Feeling nervous and excitable.
• Not able to sleep.
• Feeling sleepy.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Applies to diphenhydramine / pseudoephedrine: oral liquid, oral tablet, oral tablet disintegrating

Nervous system

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, and should avoid concomitant ingestion of alcohol.

Dystonic reactions to diphenhydramine have been accompanied by dizziness, mental confusion, rigidity, lip and tongue protrusion, trismus, torticollis, and swallowing difficulties. These reactions 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 small oral doses of diphenhydramine.[Ref]

Central nervous system (CNS) depression commonly occurs with diphenhydramine administration, resulting in drowsiness and sedation in nearly all patients treated. Motor skills may be impaired. Dystonic reactions have been reported after single doses of diphenhydramine.

Pseudoephedrine produces nervous system stimulation, resulting in tremor, anxiety, and nervousness. Insomnia is reported in up to 30% of pseudoephedrine-treated patients. Headache may also occur in patients receiving pseudoephedrine.[Ref]

Cardiovascular

Cardiovascular effects of diphenhydramine may include hypotension, tachycardia, and palpitations.

Cardiovascular adverse effects more commonly may be associated with pseudoephedrine. Pseudoephedrine generally causes a significant rise in heart rate. Hypertension and arrhythmias may be problematic in susceptible patients.[Ref]

Pseudoephedrine causes vasoconstriction which generally does not produce hypertension, but may be problematic for patients with pre-existing hypertension. Arrhythmias may be produced in predisposed patients. Rarely, pseudoephedrine has been reported to cause coronary artery spasm and chest pain.[Ref]

Hypersensitivity

Hypersensitivity reactions may occur with diphenhydramine, generally resulting in rash, pruritus and eczema. Photosensitivity reactions have also been reported with diphenhydramine.

Hypersensitivity reactions to pseudoephedrine may also occur. Fixed drug eruptions secondary to pseudoephedrine have been reported.[Ref]

Most commonly, hypersensitivity to diphenhydramine manifests itself in patients receiving systemic drug after being sensitized to it by topical application. Sensitization with systemic administration has also been reported.[Ref]

Gastrointestinal

Gastrointestinal tract adverse effects of diphenhydramine are mild, and may include nausea, dry mouth, and constipation.

Gastrointestinal adverse effects of pseudoephedrine may include anorexia and gastric irritation in approximately 5% of patients. Dry mouth, nose, or throat may occur in up to 15% of patients.[Ref]

Ocular

Ocular affects of diphenhydramine may include blurred vision, diplopia, and dry eyes due to its anticholinergic effect.[Ref]

Genitourinary

The genitourinary tract may be adversely affected due to the anticholinergic effects of diphenhydramine, resulting in urinary retention and dysuria.[Ref]

Hematologic

Hematologic adverse effects such as hemolytic anemia, thrombocytopenia, and agranulocytosis may be rarely caused by antihistamines.[Ref]

Some side effects of diphenhydramine / pseudoephedrine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.