How Benadryl eases symptoms of the common cold

The combination of acetaminophen and pseudoephedrine in antihistamines like Benadryl are used to treat stuffy nose, sinus congestion, and pain or fever caused by the common cold. Benadryl works by preventing the effects of histamine, which is produced by the body.

Decongestants (phenylephrine and pseudoephedrine) produce a narrowing of blood vessels and leads to clearing of nasal congestion. Patients who have high blood pressure should avoid its use as it may increase your blood pressure.

Analgesics (acetaminophen and salicylates for e.g., aspirin, sodium salicylate) are used to help relieve fever, headache, aches, and pain.

Special Warnings

Antihistamines may cause dizziness and drowsiness. Use caution while driving, using machinery, or doing any activity that requires alertness.

Always ask a doctor before giving cough or cold medicine to a child. Death can occur from the misuse of cough or cold medicine in very young children. Do not take more of this medication than is recommended.

If you drink more than three alcoholic beverages per day, do not take this medication without first speaking with your doctor.

Inform your doctor if you have:

  • liver disease;
  • alcoholism or cirrhosis of the liver;
  • heart disease or high blood pressure;
  • glaucoma;
  • an enlarged prostate;
  • diabetes;
  • a thyroid disorder.

This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or planning to become pregnant. Acetaminophen and pseudoephedrine may pass into breast milk and could harm a nursing baby. Tell your doctor if you are breastfeeding.

Benadryl Side Effects

Immediately stop taking Benadryl and contact your doctor if the following side effects occur:

  • fast, pounding, or uneven heartbeat;
  • severe dizziness, anxiety, restless feeling, or nervousness;
  • easy bruising or bleeding, unusual weakness, fever, chills, body aches, flu
  • increased blood pressure (severe headache, blurred vision, trouble concentrating, chest pain, numbness, seizure);
  • nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice

Keep using Benadryl and speak with your doctor if the following common side effects occur:

  • mild loss of appetite; warmth, tingling, or redness under your skin;
  • sleep problems;
  • feeling excited or restless;
  • skin rash or itching.

Avoid taking diet pills, caffeine pills, or other stimulants without your doctor’s advice. Taking a stimulant together with a decongestant can increase your risk of unpleasant side effects.

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