Nurses Compass
Drug Guide
Clemastine Fumarate
Classification
Therapeutic: Antihistamine, allergic rhinitis, hay fever, allergic conjunctivitis, urticaria
Pharmacological: H1 antihistamine
FDA Approved Indications
- Allergic rhinitis
- Urticaria (hives)
- Allergic conjunctivitis
Mechanism of Action
Clemastine Fumarate blocks H1 histamine receptors, preventing histamine from exerting its effects on target tissues, thereby alleviating allergy symptoms.
Dosage and Administration
Adult: Typically 1 mg 2-4 times daily, not exceeding 12 mg/day
Pediatric: Children aged 6-12 years: 1 mg 2-4 times daily; older children can be dosed similarly to adults
Geriatric: Start with lower dose due to increased sensitivity and potential for adverse effects; monitor closely
Renal Impairment: Adjust dose based on severity of impairment
Hepatic Impairment: Use with caution; may require dose adjustments; consult specific guidelines
Pharmacokinetics
Absorption: Rapidly absorbed from gastrointestinal tract
Distribution: Widely distributed in body tissues, crosses the blood-brain barrier
Metabolism: Minimal hepatic metabolism; primarily excreted unchanged
Excretion: Primarily via kidneys
Half Life: Around 9 hours
Contraindications
- Hypersensitivity to clemastine or other antihistamines
- Newborns or infants
Precautions
- Use with caution in elderly, in patients with glaucoma, benign prostatic hyperplasia, cardiovascular disease, hypertension, or during pregnancy and lactation
Adverse Reactions - Common
- Sedation, drowsiness (Common)
- Dry mouth (Common)
- Dizziness (Less common)
Adverse Reactions - Serious
- Palpitations, tachycardia (Rare)
- Allergic reactions (rash, angioedema) (Rare)
Drug-Drug Interactions
- CNS depressants (enhanced sedation)
- Monoamine oxidase inhibitors (potential hypertensive crisis)
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for sedation level, effectiveness of allergy symptom relief
Diagnoses:
- Ineffective airway clearance related to sedation
Implementation: Administer as scheduled, caution with operating machinery or driving
Evaluation: Assess symptom control and adverse effects regularly
Patient/Family Teaching
- Take medication exactly as prescribed
- Avoid alcohol and CNS depressants
- Caution when driving or operating machinery
- Report any excessive drowsiness or adverse reactions
Special Considerations
Black Box Warnings: N/A
Genetic Factors: None specific
Lab Test Interference: None known
Overdose Management
Signs/Symptoms: Severe drowsiness, hallucinations, convulsions, pupil dilation, tachycardia
Treatment: Supportive care, activated charcoal if ingestion recent, monitor vital signs, manage symptoms; no specific antidote
Storage and Handling
Storage: Store at room temperature, away from moisture, heat, and light
Stability: Stable for 2-3 years when stored properly