Diphenhydramine

Diphenhydramine 

Abbreviated DPH, sometimes DHM is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties that is mainly used to treat allergies.

Medical uses

Diphenhydramine is a first-generation antihistamine used to treat a number of conditions including allergic symptoms and itchiness, the common cold, insomnia, motion sickness and extrapyramidal symptoms.

Diphenhydramine is significantly more potent in treatment of allergies than a newer generation of antihistamines. Consequently, it is frequently used when an allergic reaction requires fast, effective reversal of a massive histamine release. Diphenhydramine is available as an over-the-counter drug (OTC) or prescription-only solution for injection. Injectable diphenhydramine can be used for life-threatening reactions (anaphylaxis) to allergens such as bee stings, peanuts, or latex, as an adjunct to epinephrine

What side effects can this medication cause?

Diphenhydramine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• dry mouth, nose, and throat
  
• drowsiness
  
• dizziness
  
• nausea
  
• vomiting
  
• loss of appetite
  
• constipation
  
• increased chest congestion
  
• headache
  
• muscle weakness
  
• excitement (especially in children)
  
• nervousness
• vision problems
• difficulty urinating or painful urination
  

  http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682539.html