Common Side Effects
Diphenhydramine is known to cause a variety of side effects that do not necessarily require medical attention. Most of these will go away as your body adjusts to the medication. Notify your doctor if any of the following symptoms are severe or persistent: sedation, drowsiness, dizziness, disturbed coordination, increased chest congestion, dry mouth, nose and throat, headache, muscle weakness, excitability, nervousness, loss of appetite, constipation, vomiting and nausea.
Dryness of the mouth, nose and throat may increase the occurrence of tooth decay, gum disease and fungal infections. Use sugarless candy or gum, or suck on ice chips for temporary relief if dryness persists. Talk to your doctor if this continues for more than two weeks.
Serious Side Effects
There are more serious side effects that need to be discussed with your doctor if you have been taking Benadryl for a prolonged period of time. Diphenhydramine may cause low blood pressure, palpitations, increased heart rate, confusion, nervousness, irritability, blurred vision, double vision, painful and difficulty urinating and tremors. If you experience any of these symptoms, contact your doctor immediately.
Long-Term Side Effects of Benadryl on the Brain
Older people taking products with diphenhydramine such as Benadryl may be increasing their risk for coginitive impairment, e.g., delirium, slowed thinking, Alzheimer's, etc. Dr. Malaz Boustani published findings in the May 2009 online issue of the ''Journal of Clinical Interventions in Aging'' that indicate Benadryl, as a molecule that blocks the neurotransmitter acetylcholine, interrupts the normal functioning of the central and peripheral nervous systems. Dr. Boustani also noted that the effects of Benadryl are cumulative, so the more you consume, the more of an effect this will have on the nervous system and cognition.
Read more: Long-Term Side Effects of Benadryl | eHow.com
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