| Drug and Dosage | Use | Action | Assessment: Side Effects |
|---|
| Astemizole (Hismanal)—PO 10 mg/day | Relief of allergic symptoms (rhinitis, urticaria); less sedating | Blocks the effects of histamine | Drowsiness, headache, fatigue; stimulation; dry mouth; rash; increased appetite (none of these are frequent) |
| NURSING IMPLICATIONS: Take 1 hr before or 2 hr after eating; good oral hygiene; may need to reduce calories |
| Cetirizine (Zyrtec)—PO 5–10 mg/day; 10 mg daily or twice daily for urticaria | Seasonal and perennial allergic rhinitis; chronic urticaria | Potent histamine1 (H1) receptor antagonist | Drowsiness, sedation, headache |
| NURSING IMPLICATIONS: Sedation more common in older adult. Do not take with OTC antihistamines |
| Chlorpheniramine maleate (Chlor-Trimeton)—PO 2–4 mg 3 or 4 times daily; Subcu, IM, IV 10–20 mg | Asthma; hay fever; serum reactions; anaphylaxis | Inhibits action of histamine | Nausea, gastritis, diarrhea; headache; dryness of mouth and nose; nervousness, irritability |
| NURSING IMPLICATIONS: IV may drop BP; give slowly; caution client about drowsiness |
| Diphenhydramine HCl (Benadryl)—PO 25–50 mg 3 or 4 times daily; IM, IV 10–20 mg | Allergic and pyrogenic reactions; motion sickness; radiation sickness; hay fever; Parkinson’s disease | Inhibits action of histamine on receptor cells; decreases action of acetylcholine | Sedation, dizziness, inability to concentrate; headache; anorexia; dermatitis; nausea; diplopia, insomnia |
| NURSING IMPLICATIONS: Avoid use in newborn or preterm infants and clients with glaucoma; supervise ambulation; caution against driving or operating mechanical devices; excitation or hallucinations may occur in children |
| Fexofenadine (Allegra)—PO 50 mg twice daily | Seasonal allergic rhinitis; chronic urticaria | Antagonizes histamine at the H1 receptor site | Headache, drowsiness, fatigue; dyspepsia; throat irritation |
| NURSING IMPLICATIONS: Monitor effectiveness; well tolerated; consult physician if breastfeeding |
| Loratidine (Claritin)—PO 10 mg daily on empty stomach | Seasonal allergic rhinitis; idiopathic chronic urticaria | Selective peripheral H1 receptor sites, blocking histamine release | Dizziness; dry mouth, thirst; fatigue; headache |
| NURSING IMPLICATIONS: Causes significant drowsiness in older adult |
| Nedocromil (Tilade)—inhalation 2 sprays | Asthma | Prevents the release of histamine from sensitized mast cells | Hypersensitivity, acute asthma attacks; does not relieve (may accelerate) bronchospasm |
| NURSING IMPLICATIONS: Monitor pulmonary function; use only as prescribed; if symptoms increase, notify health-care professional; teach proper use of metered-dose inhaler |