The commercial name of this first generation antihistamine is better known. Few people know that diphenhydramine is the active substance of Diphenhydramine. A new wave of interest in the drug is caused by its strong anti-allergic effect and soothing properties, useful for insomnia.

Trade Name Diphenhydramine

The generic name of the active substance appeared in 1943 after the discovery of Professor D. Reyves in the United States.

Three years later, diphenhydramine was recognized as a drug that blocks histamine H1 receptors.

Later sleeping pills and anxiolytic effects were discovered.

The best known trade name for diphenhydramine is Diphenhydramine. The drug belongs to the group of H1-antihistamines, used for allergies. Also, "Diphenhydramine" is used as a local anesthetic, sedative, hypnotic and antiemetic. Diphenhydramine increases the level of serotonin in the brain, thus acting against depression and increased anxiety.

Which preparations include

In tablets and injectable solutions sold under the trade name "Diphenhydramine", the active substance is present in the form of diphenhydramine hydrochloride. This is a white crystalline substance. Dosages in tablets - 30, 50, 100 mg. The solutions contain 10 mg / ml diphenhydramine.

Another dosage form is the Psilo-Balsam gel. The drug contains 10 mg / g of diphenhydramine. The product is used externally to reduce rashes, itching of the skin with hives, dermatitis, chickenpox, insect bites, thermal and chemical burns.

Diphenhydramine is a component of the following combination drugs:

  • Migrenol PM tablets, in addition to 25 mg of antihistamine, contain 500 mg of paracetamol. The tool belongs to the group of analgesics, it is used for pain syndrome of various localization: head, tooth, muscle, joint. Migrenol PM is prescribed for sinusitis with facial pain and fever, cough, PMS, insomnia due to restless legs syndrome, catarrhal disease.
  • Drops for oral administration "Valemidine" in addition to diphenhydramine (diphenhydramine) contain tinctures of plants (mint, valerian, motherwort, hawthorn). Prescribe the drug for neurosis and hypertension.
  • The similar composition and indications of another herbal remedy is Valeodicramen. The components are the same, only in different ratios.
  • Syrup "Cofanol" has an antiallergic expectorant, anti-inflammatory, sedative effect. Antiemetic and antispasmodic properties are less pronounced.
  • "Antigrippin" and "Antigrippin-ANVI" - drugs produced in the form of capsules. They are used for the symptomatic treatment of colds, SARS, flu. As active substances, the composition includes acetylsalicylic acid, vitamin C, rutoside, metamizole sodium, calcium gluconate and diphenhydramine.
  • Ophthalmoferon eye drops - a combination of interferon alpha-2b and diphenhydramine. The tool is used to treat viral conjunctivitis, keratitis, uveitis.
  • "Pentaflucin" - soluble granules in disposable bags. The drug contains paracetamol, vitamin C, diphenhydramine and rutin. Pentaflucin is used to relieve symptoms of acute respiratory infections.

Pharmacological action, pharmacodynamics and pharmacokinetics

Diphenhydramine and other H1 antihistamines are part of a larger group of drugs - histaminolytics. The action of such drugs is aimed at blocking the interaction of the mediator of histamine inflammation with receptors sensitive to it in the tissues.

H1 receptor blockers help with allergic diseases of various localization. Diphenhydramine is an antihistamine of the first generation. This and other drugs that appeared later inhibit the response of tissues to histamine, as they replace the mediator. As a result, the processes characteristic of the action of histamine and similar substances (acetylcholine, etc.) are significantly weakened or not occur.

Antihistamines reduce hypotension, spasms of smooth muscles (intestines, bronchi), normalize the permeability of the walls of the capillaries. Thanks to the use of H1 receptor blockers, edema due to the action of histamine does not develop, itching and redness disappear. In general, the course of an allergic reaction is facilitated or changes characteristic of an allergy do not occur. In addition, the cough reflex is suppressed due to the effect on the cough center in the brain.

Diphenhydramine is rapidly absorbed, distributed in tissues. The maximum activity of the drug develops within an hour. The medicine decomposes in the liver into physiologically inactive metabolites. Metabolism is excreted through the kidneys and urinary tract.

The medicine works quickly, but shortly. Therefore, the drug is taken orally up to 4 times a day. With prolonged treatment, antihistamines, sedatives, hypnotics, and other therapeutic effects are weakened.

These disadvantages are also characteristic of diphenhydramine analogues - promethazine (part of Pipolfen), chloropyramine (trade name Suprastin).

Diphenhydramine inhibits a number of central nervous system functions, enhances the effect of narcotic and non-narcotic painkillers simultaneously taken by patients.Some pharmacological effects associated with an antihistamine effect are undesirable. Medications that are related to the first generation of H1 receptor blockers are less and less prescribed by doctors.

What is the first generation antihistamine prescribed for?

Diphenhydramine relieves the symptoms of many diseases and syndromes. The drug is prescribed for urticaria, hay fever, Quincke's edema, allergic conjunctivitis and rhinitis, dermatoses that occur with skin itching. Take a tool to facilitate falling asleep and with sleep disorders. Use with caution with vomiting in pregnant women, motion sickness, Meniere's syndrome. In all cases, the drug should be taken in a short course.

Instructions for use and dosage of diphenhydramine

The route of administration of the drug is oral, in / m and / in. To properly treat allergies or sleep disorders, you can use the recommendations in the instructions for use of "Diphenhydramine".

Inside, children are prescribed 10 to 30 mg of diphenhydramine. Take the medicine from 1 to 3 times a day for 10 to 15 days. Adults can take 25-50 mg of diphenhydramine once a day. It is recommended to swallow the tablet whole, drink it with water. Better to take 15 to 30 minutes before bedtime. The course of treatment for adults is also about 2 weeks.

Dosage for IM administration is from 1 to 5 ml of a 1% solution.

It should be ensured that after taking the pill or injection the patient can fully sleep 7-8 hours. If the dream is short, then in the morning a person will feel tired, lethargic, weak, unable to concentrate on study or work.

During pregnancy and lactation

During pregnancy, diphenhydramine is prescribed with great care, according to strict indications, under the supervision of a gynecologist and therapist. Animal studies have shown that the drug can have a teratogenic effect. A study of the effect of the drug on pregnant women has not been conducted.

During lactation, the same rules apply. At the time of taking diphenhydramine, breastfeeding should be interrupted. It is important that the health benefits of the mother are greater than the risks to the baby.

Drug interaction

Diphenhydramine increases the hypotensive effect of drugs to reduce blood pressure. With simultaneous use, the effect of drugs that depress the central nervous system is enhanced. This must be taken into account during treatment with tranquilizers, antihistamines, sedatives and hypnotics.

Do not use analgesics and anticonvulsants at the same time, or their dosages should be reduced. Otherwise, the effect of the drugs will increase excessively, which can lead to unpredictable health consequences.

Contraindications, side effects and overdose

You can not use diphenhydramine with increased sensitivity to this medicine, heart disease (impaired conduction, ischemia, arrhythmia). Contraindications are epilepsy, prostatitis with urinary retention, metabolic disorders of potassium and magnesium, glaucoma.

An I generation antihistamine may show the following undesirable effects:

  • causes drowsiness, dizziness; weakness, nausea;
  • reduces attention span;
  • enhances urination;
  • causes gastrointestinal dysfunction;
  • drains the mucous membranes;
  • impairs vision.

Other possible side effects associated with taking the drug include diarrhea or constipation, heartburn, hand shake, agitation, and sleep disturbances. In case of an overdose, all of these effects may increase. Hallucinations appear, the work of the cardiovascular system is disrupted.

Preferred antihistamines of later generations. Newer drugs have many advantages: quick and lasting effect, as well as the absence of most of the side effects characteristic of diphenhydramine.

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