Index
In a general sense, it is an antihistamine widely used to treat different allergic reactions.
Also, histamine is released throughout the body and is affected by several types of allergic reactions and, to a lesser extent, during viral infections, such as the common cold.
When histamine binds to the receptors in the cells, then it stimulates changes within the cells that lead to the release of chemicals that cause sneezing, itching, and increased production of nasal secretions.
The antihistamines compete with histamine for cell receptors, and receptors bind to unstimulated cells. In addition, they prevent histamine from binding and stimulating the cells.
Diphenhydramine also blocks the action of acetylcholine (anticholinergic effect) and is used as a sedative because it causes drowsiness. The FDA originally approved diphenhydramine in 1946.
What are the side effects of diphenhydramine?
Diphenhydramine can commonly cause:
- Sedation.
- Fatigue.
- Drowsiness.
- Dizziness.
- Constipation.
- Disturbed coordination.
- Drying and thickening oral secretions and other respiratory secretions and urinary retention.
Diphenhydramine can also cause:
- Low blood pressure .
- Palpitations (abnormal heartbeat).
- Increased heart rate
- Confusion.
- Nervousness.
- Irritability.
- Blurry vision.
- Double vision.
- Pain when urinating or difficulty urinating.
- Temblor.
- Perspiration.
- Loss of appetite
- Erectile dysfunction.
- Nausea.
However, the person who should use diphenhydramine should use it with caution (if it is administered), especially in people with narrow-angle glaucoma, prostatic hypertrophy (enlargement of the prostate), hyperthyroidism, cardiovascular disease, high blood pressure ( hypertension). ) and, finally, asthma.
What is the dose of diphenhydramine?
The doses of diphenhydramine vary depending on the formulation and have their maximum effect about one hour after the drug in question is taken.
For example, when it is used to treat sleep disorders such as insomnia, it is prescribed at bedtime. Individuals older than 60 years are susceptible to diphenhydramine’s sedative and anticholinergic effects, and the dose should be reduced.
A typical regimen for treating allergic reactions in adults is 25-50 mg every 4-6 hours, which does not exceed 300 mg a day.
Insomnia is treated with 50 mg taken 30 minutes before going to bed.
What medications or supplements interact with diphenhydramine?
Diphenhydramine increases (exaggerates) the sedative effects of alcohol and other drugs that can cause sedation- Classic examples are presented in the following medications according to their class:
- As the benzodiazepine class of anxiety (for example, diazepam [Valium], lorazepam [Ativan], clonazepam [Klonopin], alprazolam [Xanax]).
- The narcotic class of analgesics and their derivatives (for example, oxycodone and paracetamol [Percocet], hydrocodone and paracetamol [Vicodin], guaifenesin with hydromorphone [Dilaudid], codeine, propoxyphene [Darvon])
- The tricyclic class of antidepressants (for example, amitriptyline [Elavil, Endep], imipramine [Tofranil], desipramine [Norpramin])
- And certain antihypertensive medications (for example, clonidine [Catapres], propranolol [Inderal]).
- Diphenhydramine may also intensify the drying effects of other drugs with anticholinergic properties (e.g., dicyclomine [Bentyl] and botanical [Urecholine], probation).
Is it safe to take diphenhydramine if I am pregnant or breastfeeding?
Diphenhydramine has not been adequately evaluated in pregnant women. It should be used only if the benefit outweighs the potential but unknown risks.
Lactation: Diphenhydramine is secreted in breast milk. Because of the risk of stimulation and seizures in babies, especially newborns and premature babies, nursing mothers should not use antihistamines.
Presentations
- Capsules: 25 and 50 mg.
- Tablets: 12.5, 25 and 50 mg.
- Tablet (chewable or dispersible): 12.5 mg.
- Strips: 12.5 and 25 mg.
- Elixir, oral solution, liquid: 12.5 mg per teaspoon (5 mL).
- Injection: 50 mg per ml.
How should I keep the diphenhydramine stored?
Diphenhydramine should be stored at room temperature from 15 ° C to 30 ° C (59 ° F to 86 ° F), and the injection should be protected from freezing and light.
Summary
It is an over-the-counter and prescription drug used to treat:
- Hay fever.
- Urticaria.
- Allergic conjunctivitis.
- Cinetosis.
