diphenhydrAMINE [Benadryl] - *ALS only**

Question 1

Classification

Benadryl

Answer 1

antihistamine

Question 2

Indications

Benadryl

Answer 2

ACP

• adjunct treatment of hypersensitivity reaction

Question 3

Contraindications

Benadryl

Answer 3

• hypersensitivity to antihistamines
• neonates
• premature infants

Question 4

Dosage - Adult

Benadryl

Answer 4

ACP
50mg IM/IV or
1mg/kg MAX 50mg

Question 5

Dosage - Pediatric

Benadryl

Answer 5

ACP
1mg/kg IM/IIV
MAX 50mg

Question 6

Pharmacodynamics

Benadryl

Answer 6

• anticholinergic (drying) and sedative side effects.
• appears to compete with histamine for cell receptor sites on effector cells

Question 7

Pharmacokinetics

Benadryl

Answer 7

Onset - 30-60mins IM ; 5-10mins IV
Peak - 1-4hrs IM/IV
Half-life - 1-4hrs IM/IV
Duration - 4-6hrs IM/IV

Question 8

Precautions

Benadryl

Answer 8

Has an *atropine-like action and therefore, should be used with caution in patients with:

• A history of bronchial asthma
• Increased intraocular pressure
• Hyperthyroidism
• Cardiovascular disease
• Hypertension
• Lower respiratory disease

Question 9

Adverse Effects (CNS)

Benadryl

Answer 9

Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, parethesia, blurred vision, diplopi, vertigo, tinnitus, acute labyrinthitis, neuritis, convulsions

Question 10

Adverse Effects

Benadryl

Answer 10

• Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose and throat
• Hypotension, headache, palipations, tachycardia, extrasystoles
• Hemolytic Anemia, thrombocytopenia, agranulocytosis
• Epigasric distress, anorexia, nausea, vomiting, diarrhea, constipation
• Thickening of bronchial secretions, tightness of chest or throat and wheezing, nasal stuffiness

Question 11

Drug to Drug

Benadryl

Answer 11

• potentiates effects w/ ETOH and other CNS depressants (hypnotics, sedative, tranquilizers, etc.)
• MAO inhibitors prolong and intesnsify the anticholinergic (drying) effect of antihistamines

Question 12

Warnings

Benadryl

Answer 12

Use with caution in patients with:

• Narrow-angle glaucoma
• Stenosing peptic ulcer
• Pyloroduodenal obstruction
• Symptomatic prostatic hypertrophy
• Bladder-neck obstruction