Diphenhydramine : Therapeutic uses, Clinical uses, Indications, Dosage, Side Effects, Warnings, Interactions, Precautions, Contraindications & Brand names
Diphenhydramine (DPH, DHM) is a first generation H1- receptor blocker (Anti-histamine), useful in treating & preventing the allergic reactions like-Hey fever, sneezing etc.
Route : Oral
Plasma half-life : 7-17 hours
Duration of action : 12 hours
Bioavailability :40–60%
Chemical formula :C17H21NO
IUPAC name :2-(diphenylmethoxy)-N,N-dimethylethanamine
Trade name : Benadryl, Unisom, Sominex, Banophen, ZzzQuil, Allermax, Compoz Nighttime Sleep Aid, Diphedryl, Diphenhist, Dytuss, Nytol QuickCaps, Silphen Cough, Simply Sleep, Sleepinal, Theraflu Thin Strips Multi Symptom, Tranquil, Triaminic Thin Strips Allergy, Twilite, Unisom Sleepgels Maximum Strength, Valu-Dryl, Z-Sleep plus
Therapeutic uses : Diphenhydramine has following usage :
- Useful in treating & preventing the allergic reactions like-Hey fever, sneezing, runny nose, itching, watery eyes, skin rash & hives and common cold.
- Along with anti-muscarinic agent like- Scopolamine, it can be used for prevention of symptoms of Motion sickness. They are usually not effective if symptoms are already present and, thus, should be taken prior to expected travel.
- It can be used to prevent or diminish nausea and vomiting mediated by both the chemoreceptor and vestibular pathways.
- It have strong sedative properties and are used in the treatment of insomnia (Somnifacient/Sleep aid).
Side effects : First-generation H1-receptor blockers have a low specificity, interacting not only with histamine receptors but also with muscarinic cholinergic receptors, α-adrenergic receptors, and serotonin receptors.Some side effects may be undesirable, and others may be of therapeutic value, Following side effects are elicited:
On CNS
- Sedation (most frequently observed adverse reaction),
- Diminished alertness and concentration,
- Fatigue, lassitude, tinnitus, dizziness, tendency to fall asleep,
- Lack of coordination (Motor incoordination), and tremors,
- Light headedness, headache, euphoria, nervousness,
- Blurring of vision, Diplopia
On GIT
- Alteration of bowel movement,
- Epigastric distress,
- Dryness of mouth,
- Urinary hesitancy( urinary retention or frequency, and dysuria),
- Acute overdose(acute poisoning) exhibits various adverse effects, most common and dangerous effects on the CNS like central excitation, tremors, hallucinations, ataxia, muscular incoordination, convulsions, and flushing, hypotension, fever & some other features of belladonna poisoning. If untreated, the patient may experience a deepening coma and collapse of the cardio-respiratory system resulting in Death.
Note:- Although the margin of safety of H1-receptor blockers is relatively high, and chronic toxicity is rare, acute poisoning is relatively common, especially in young children.
Drug Interactions: Diphenhydramine may interact with following drugs :
Precautions
Before using this medication, tell your doctor or pharmacist
- If you are allergic to it; or if you have any other allergies.
- Your medical history, especially of respiratory problems, glaucoma, heart problems, high bp, liver disease, seizures, GIT problems, hyperthyroidism, urinary problems.
Contraindications
- This drug should not be used in neonates or premature infants.
For detailed query or in case of uncertainty, Always consult your doctor or pharmacist.
