antihistamines should be used with considerable caution in patients with narrow-angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, or bladder-neck obstruction. not recommended for children with chronic lung disease or glaucoma.
for external use only. do not use on chicken pox, measles or extensive areas of skin. if condition worsens or persists for more than 7 days, consult a physician. do not use other drugs containing diphenhydramine while using this product.
in infants and children, especially, antihistamines in overdosage may cause hallucinations, convulsions, or death. as in adults, antihistamines may diminish mental alertness in children. in the young child, particularly, they may produce excitation.
geriatrics (approximately 60 years or older):
antihistamines are more likely to cause dizziness, sedation and hypotension in elderly patients.
use benadryl cautiously if you have a history of asthma or other chronic lung disease, an over-active thyroid, high blood pressure, or heart disease.
medlineplus drug information: antihistamines (systemic)