Outline

I. Introduction

• Definition and overview
• Common uses and forms

II. How Diphenhydramine Works

• Mechanism of action
• Effects on the body

III. Common Uses

• Allergy relief
• Treatment of insomnia
• Motion sickness prevention
• Cough suppression

IV. Dosage and Administration

• General guidelines
• Specific dosages for different conditions
• Administration methods (tablets, liquid, topical)

V. Side Effects and Precautions

• Common side effects
• Serious side effects and warnings
• Precautions for use (e.g., pregnancy, medical conditions)

VI. FAQs about Diphenhydramine

What is Diphenhydramine?

Diphenhydramine is an antihistamine primarily used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose, and sneezing. It is also used to prevent and treat nausea, vomiting, and dizziness caused by motion sickness, and to induce sleep.

How Does Diphenhydramine Work?

Diphenhydramine works by blocking the effects of histamine, a substance in the body that causes allergic symptoms. By inhibiting histamine, it helps reduce symptoms like itching, swelling, and rashes. Additionally, diphenhydramine has sedative properties, making it effective for treating insomnia and motion sickness.

Common Uses of Diphenhydramine

1. Allergy Relief: Eases symptoms like runny nose, sneezing, and itching.
2. Sleep Aid: Helps with short-term treatment of insomnia due to its sedative effects.
3. Motion Sickness: Prevents and alleviates symptoms like nausea and dizziness.
4. Cough Suppression: Often included in cough and cold medications to reduce cough reflex.

Dosage and Administration

Diphenhydramine is available in various forms, including tablets, capsules, liquid, and topical creams. The dosage varies based on the condition being treated, age, and form of the medication. Always follow the instructions provided by your healthcare provider or the packaging.

General Dosage Guidelines:

• For Allergies: Adults and children over 12 years: 25-50 mg every 4-6 hours, not exceeding 300 mg per day.
• For Insomnia: Adults: 50 mg at bedtime.
• For Motion Sickness: Adults and children over 12 years: 25-50 mg taken 30 minutes before travel and continued every 4-6 hours as needed.

Side Effects and Precautions

While diphenhydramine is generally safe when used as directed, it can cause side effects. Common side effects include:

• Drowsiness
• Dizziness
• Dry mouth, nose, or throat
• Constipation
• Blurred vision

Serious Side Effects:

• Difficulty urinating
• Rapid or irregular heartbeat
• Severe drowsiness or confusion (especially in older adults)

Precautions

1. Avoid Alcohol: Consuming alcohol can increase drowsiness and dizziness.
2. Driving and Operating Machinery: Due to its sedative effects, avoid activities requiring alertness.
3. Pregnancy and Breastfeeding: Consult your doctor before use.
4. Medical Conditions: Inform your doctor if you have asthma, glaucoma, heart problems, or other chronic conditions.

FAQs 

Q1: Can I take diphenhydramine every night for insomnia? A: It’s not recommended for long-term use due to potential dependence and side effects. Consult your doctor for chronic insomnia.

Q2: Is it safe to use diphenhydramine for children? A: Yes, but always follow the pediatric dosing guidelines and consult a pediatrician.

Q3: Can I use diphenhydramine if I am pregnant? A: Consult your doctor before use, as it should only be used if clearly needed.

Q4: How quickly does diphenhydramine take effect? A: It usually starts working within 30 minutes and lasts for 4-6 hours.

Q5: Can I use diphenhydramine topically and orally at the same time? A: It’s best to avoid combining both forms to prevent excessive absorption and side effects.