Diphenhydramine is an antihistamine. Phenylephrine is a decongestant.

Dytan-D is a combination medicine used to treat runny or stuffy nose, sneezing, itching, watery eyes, and sinus congestion caused by allergies, the common cold, or the flu.

Dytan-D may also be used for purposes not listed in this medication guide.

Do not use Dytan-D if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, and tranylcypromine, and others.

Use this medicine exactly as directed. Taking too much diphenhydramine can lead to serious heart problems, seizures, coma, or death.

Do not use this medicine to make a child sleepy. Ask a doctor before giving the medicine to a child younger than 6 years old.

Ask a doctor or pharmacist before using any other medicine that may contain diphenhydramine. Taking too much of this medicine can lead to a fatal overdose.

Use exactly as directed on the label, or as prescribed by your doctor. Cold or cough medicine is only for short-term use.

Always follow directions on the medicine label about giving cough or cold medicine to a child. Do not use the medicine only to make a child sleepy. Death can occur from the misuse of cough or cold medicines in very young children.

Ask a doctor before giving the medicine to a child.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

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 or medical tests, tell the doctor ahead of time if you have taken a cold medicine within the past few days.

Store at room temperature away from moisture and heat.

Do not use Dytan-D if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, and tranylcypromine, and others.

Ask a doctor or pharmacist if Dytan-D is safe to use if you have ever had:

• asthma or COPD, cough with mucus, or cough caused by smoking, emphysema, or chronic bronchitis;

• high blood pressure, heart disease;

• an enlarged prostate or urination problems;

• glaucoma;

• diabetes; or

• a thyroid disorder.

This medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

Since Dytan-D is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of diphenhydramine and phenylephrine can be fatal.

Overdose symptoms may include vomiting, confusion, severe drowsiness, ringing in your ears, no urination, very dry eyes and mouth, dilated pupils, fast heartbeats, tremor, agitation, hallucinations, or seizure.

Avoid driving or hazardous activity until you know how Dytan-D will affect you. Your reactions could be impaired.

Ask a doctor or pharmacist before using any other medicine that may contain diphenhydramine. This includes medicines for sleep, cold/allergy symptoms, or anti-itch medicine used on the skin. Using too much diphenhydramine may lead to a fatal overdose.

Drinking alcohol with this medicine can cause side effects.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Dytan-D may cause serious side effects. Stop using Dytan-D and call your doctor at once if you have:

• severe drowsiness;

• sleeplessness;

• painful or difficult urination;

• fast, pounding, or uneven heartbeats;

• trouble breathing;

• anxiety, nervousness;

• a seizure; or

• problems with balance or speech.

Common side effects of Dytan-D may include:

• dizziness, drowsiness, headache;

• dry mouth, nose, or throat;

• nausea, vomiting, constipation;

• blurred vision; or

• trouble sleeping.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1 800 FDA 1088.

Ask a doctor or pharmacist before using Dytan-D with any other medicines, especially drugs that can cause drowsiness (such as opioid medication, sleep medicine, a muscle relaxer, or medicine for anxiety or seizures). Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.