The 44 329 pink pill is an over-the-counter (OTC) film-coated tablet containing Diphenhydramine Hydrochloride 25 mg. It is a widely distributed generic equivalent to brand-name Benadryl Allergy Ultratabs and is produced by major store-brand suppliers (such as LNK International) for retailers including CVS, Equate (Walmart), Rite Aid, and Walgreens.
Diphenhydramine is a first-generation receptor antihistamine known for both its allergy-relieving properties and strong central nervous system (sedative) effects.
Pill Identification
Attribute Details
- Active Ingredient – Diphenhydramine Hydrochloride (25 mg)
- Imprint Code – 44 329 or 44-329
- Color – Pink
- Shape – Oval / Oblong
- Size – ~11 mm
- Brand Equivalence – Generic version of Benadryl Allergy Ultratabs
- Drug Class – First-generation Antihistamine / Anti-emetic / Sleep Aid
Mechanism of Action
Diphenhydramine functions primarily as a competitive antagonist of histamine at the receptor site:
- Histamine Blockade: When exposed to allergens (pollen, pet dander, dust), the immune system releases histamine. Diphenhydramine blocks receptors in the respiratory tract, blood vessels, and skin, stopping symptoms such as sneezing, runny nose, itching, and watery eyes.
- Central Nervous System Penetration: Unlike non-drowsy (second-generation) antihistamines like loratadine or cetirizine, diphenhydramine readily crosses the blood-brain barrier. Once in the central nervous system, it blocks central receptors, producing significant drowsiness, sedation, and anti-anxiety effects.
- Anticholinergic Activity: Diphenhydramine also possesses potent antimuscarinic (anticholinergic) properties. By blocking acetylcholine receptors, it reduces bronchial secretions, dries up nasal passages, and inhibits the brain’s vomiting center (making it useful for motion sickness).
Indications & Dosage
Uses
- Upper Respiratory Allergies & Hay Fever: Temporary relief of sneezing, runny nose, itchy/watery eyes, and itching of the nose or throat.
- Common Cold Symptoms: Relief of runny nose and sneezing due to colds.
- Off-Label / Nighttime Sleep Aid: Used short-term to treat occasional insomnia due to its sedating effects.
- Motion Sickness & Urticaria: Management of mild skin hives or prevention of motion sickness.
Standard Oral Dosage Guidelines
- Adults and Children 12 Years and Older: 1 to 2 tablets (25 mg to 50 mg) every 4 to 6 hours as needed. Do not exceed 6 doses (300 mg) in 24 hours.
- Children 6 to under 12 Years: 1 tablet (25 mg) every 4 to 6 hours. Do not exceed 6 tablets (150 mg) in 24 hours.
- Children under 6 Years: Do not use without explicit pediatrician authorization.
Side Effects
Because diphenhydramine affects both the central nervous system and peripheral cholinergic receptors, side effects are common:
Very Common Side Effects
- Marked Drowsiness and Fatigue: Lethargy, reduced reaction speed, and daytime grogginess.
- Anticholinergic “Dry” Symptoms: Dry mouth, nose, and throat; constipation; reduced sweating.
- Dizziness & Unsteadiness: Impaired motor coordination or lightheadedness.
- Thickening of Mucus: Hardening of bronchial secretions in the lungs.
Paradoxical Reactions
- CNS Excitability: Especially in young children or elderly individuals, diphenhydramine can sometimes cause restless agitation, insomnia, hyperactivity, nervousness, or rapid heart rate instead of sedation.
Precautions & Warnings
Central Nervous System Impairment
- Avoid Alcohol & Sedatives: Do not consume alcohol, tranquilizers, or prescription sedatives while taking diphenhydramine, as they synergistically amplify drowsiness and cognitive slowdown.
- Operating Machinery: Extreme caution is required when driving or operating heavy machinery.
Pre-existing Medical Conditions
Consult a healthcare provider before taking if you have:
- Glaucoma (Narrow-Angle): Anticholinergic action can increase intraocular pressure.
- Prostate Enlargement / Urinary Retention: Can worsen difficulty urinating or cause acute bladder outlet obstruction.
- Breathing Disorders: Chronic bronchitis, emphysema, or severe asthma (due to mucus thickening).
Safety Contraindications
- Do Not Combine: Never use with any other products containing diphenhydramine, including topical creams, gels, or sprays (to avoid systemic overdose).
- Pediatric Sedation Warning: Never use this medication to make a child sleep or sedate them.
- Geriatric Risk (Beers Criteria): Older adults are significantly more sensitive to anticholinergic side effects (increased risk of confusion, delirium, urinary retention, severe constipation, and fall risks).