Nurses Compass
Drug Guide
Diphenylpyraline Hydrochloride
Classification
Therapeutic: Antihistamine, Anticholinergic
Pharmacological: Piperidine derivative antihistamine with anticholinergic properties
FDA Approved Indications
- Allergic conditions such as hay fever, allergic conjunctivitis, allergic rhinitis, urticaria, and other allergic skin reactions
Mechanism of Action
Diphenylpyraline acts by blocking H1 histamine receptors, thereby preventing histamine-mediated allergic responses. Its anticholinergic properties contribute to its additional effects such as decreasing secretions and alleviating muscle spasms.
Dosage and Administration
Adult: Usually 15-30 mg orally in divided doses per day, adjusted based on response and tolerability.
Pediatric: Not commonly used in children; consult specific pediatric dosing guidelines.
Geriatric: Start at lower doses due to increased sensitivity and potential for anticholinergic side effects.
Renal Impairment: Use with caution; dose adjustment may be necessary.
Hepatic Impairment: Use with caution; monitor for increased sedation or toxicity.
Pharmacokinetics
Absorption: Well absorbed from gastrointestinal tract.
Distribution: Widely distributed in body tissues; crosses the blood-brain barrier.
Metabolism: Metabolized in the liver.
Excretion: Primarily excreted via urine.
Half Life: Approximately 4-6 hours.
Contraindications
- Hypersensitivity to diphenylpyraline or other phenothiazines.
- Narrow-angle glaucoma.
- Prostatic hypertrophy with urinary retention.
Precautions
- Use cautiously in patients with asthma, urinary retention, or cardiovascular disease. Due to anticholinergic side effects, use cautiously in the elderly. Pregnancy and lactation should be discussed with a healthcare provider.
Adverse Reactions - Common
- Sedation or drowsiness (Common)
- Dry mouth (Common)
- Dizziness (Uncommon)
Adverse Reactions - Serious
- Urinary retention (Rare)
- Allergic reactions including rash, itching (Rare)
- Cardiovascular effects such as tachycardia (Rare)
Drug-Drug Interactions
- CNS depressants (enhanced sedation)
- Monoamine oxidase inhibitors (risk of hypertensive crisis)
Drug-Food Interactions
- Alcohol (increased sedative effects)
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for sedation, anticholinergic side effects, and allergic reactions.
Diagnoses:
- Risk for falls due to sedation or dizziness
- Impaired oral mucous membrane related to dry mouth
Implementation: Administer with food if GI upset occurs. Avoid alcohol and CNS depressants. Monitor patient response.
Evaluation: Assess effectiveness in relieving allergy symptoms and monitor for adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Avoid alcohol and operating heavy machinery until response is known.
- Report any excessive sedation, dry mouth, urinary retention, or allergic symptoms.
- Do not discontinue abruptly to avoid rebound allergy.
Special Considerations
Black Box Warnings:
- None specifically for diphenylpyraline
Genetic Factors: Genetic variations in drug metabolism may affect response.
Lab Test Interference: May interfere with certain skin allergy testing results due to antihistamine properties.
Overdose Management
Signs/Symptoms: Severe drowsiness, hallucinations, agitation, tachycardia, urinary retention, dry mouth, blurred vision.
Treatment: Supportive care, activated charcoal if ingestion is recent, and symptomatic treatment. Consider gastric lavage in severe cases. Consult poison control for further guidance.
Storage and Handling
Storage: Store at room temperature away from moisture, heat, and light.
Stability: Stable when stored properly. Check expiration date before use.