Diphenhydramine is an antihistamine that is primarily used to treat allergies. It is also used for insomnia, common cold symptoms, tremor in parkinsonism, and nausea. It is used by mouth, injection into blood vessels, and injections into the muscles. The maximum effect is usually about two hours after the dose, and the effect can last up to seven hours.
Common side effects include drowsiness, poor coordination, and abdominal pain. Its use is not recommended in infants. There is no apparent risk of danger when used during pregnancy; However, use during breastfeeding is not recommended. This is a first generation H1-antihistamine and works by blocking certain histamine effects. Diphenhydramine is also an anticholinergic.
Diphenhydramine was first made by George Rieveschl and commenced commercial use in 1946. It is available as a generic drug. The wholesale price in developing countries in 2014 is about US $ 0.01 per dose. In the United States, it costs less than US $ 25 for regular monthly inventory. It is sold under the trade name Benadryl, among others.
Video Diphenhydramine
Medical use
Diphenhydramine is the first-generation antihistamine used to treat a number of conditions including allergy symptoms and hives, common colds, insomnia, motion sickness, and extrapyramidal symptoms. Diphenhydramine also has local anesthetic properties, and has been used as in people who are allergic to local anesthetics such as lidocaine.
Allergic
Diphenhydramine is effective in the treatment of allergies. In 2007 it was the most commonly used antihistamine for acute allergic reactions in the emergency department.
With injections it is often used in addition to epinephrine for anaphylaxis. Its use for this purpose has not been properly studied in 2007. Its use is recommended only after acute symptoms improve.
Topical formulations of diphenhydramine are available, including creams, lotions, gels, and sprays. It is used to relieve itching and has the advantage of causing less systemic effects ( eg. , drowsiness) than the oral form.
Motion impairment
Diphenhydramine is used to treat extrapyramidal symptoms such as Parkinson's disease caused by antipsychotics.
Sleep
Due to its sedative nature, diphenhydramine is widely used in non-prescription sleep aids for insomnia. It is an ingredient in some products sold as a sleep aid, either alone or in combination with other ingredients such as acetaminophen (paracetamol). The last example is Tylenol PM. Diphenhydramine can cause small psychological dependence. Diphenhydramine can cause sedation and has also been used as anxiolytic.
Nausea
Diphenhydramine also has antiemetic properties, which makes it useful in treating the nausea that occurs in vertigo and motion sickness.
Custom population
Diphenhydramine is not recommended for people older than 60 or children under the age of six, unless a doctor is consulted. This population should be treated with second-generation antihistamines such as loratadine, desloratadine, fexofenadine, cetirizine, levocetirizine, and azelastine. Due to its strong anticholinergic effect, diphenhydramine is on the "beer list" of drugs to avoid in the elderly.
Diphenhydramine is a category B in the FDA Classification of Drug Safety During Pregnancy. It is also excreted in breast milk. The paradoxical reaction to diphenhydramine has been documented, especially among children, and can lead to excitation rather than sedation.
Topical diphenhydramine is sometimes used primarily for people in care homes. This use without topical indications and diphenhydramine should not be used as a treatment for nausea because studies do not show this therapy more effectively than alternatives.
Maps Diphenhydramine
Adverse effects
The most prominent side effect is sedation. The common dose of creating a driving disorder is equivalent to a blood alcohol level of 0.10 higher than the 0.08 limit of most drunk driving laws.
Diphenhydramine is a powerful anticholinergic agent. This activity is responsible for side effects of dry mouth and throat, increased heart rate, pupil dilatation, urinary retention, constipation, and, at high doses, hallucinations or delirium. Other side effects include motor disorders (ataxia), reddened skin, blurred vision near due to lack of accommodation (cycloplegia), abnormal sensitivity to bright light (photophobia), sedation, difficulty concentrating, short-term memory loss, vision impairment, irregular breathing, dizziness, irritability, itchy skin, confusion, increased body temperature (in general, on hand and/or foot), temporary erectile dysfunction, and stimulation, and although it can be used to treat nausea, higher doses may cause vomiting.
Some people have allergic reactions to diphenhydramine in the form of itching. However, anxiety or akathisia can also be a side effect exacerbated by an increase in diphenhydramine levels, especially with recreational doses. Because diphenhydramine is widely metabolized by the liver, care should be taken when administering drugs to individuals with liver disorders.
Long-term anticholinergic use was associated with an increased risk of cognitive decline and dementia among parents.
Overdose
Diphenhydramine overdose symptoms may include
Acute poisoning can be fatal, leading to cardiovascular collapse and death within 2-18 hours, and generally treated using a symptomatic and supportive approach. The diagnosis of toxicity is based on clinical history and presentation, and at the general specific level is useless. Several levels of strong evidence suggest that diphenhydramine (similar to chlorpheniramine) can block delayed receptor potassium channels and, as a result, prolong the QT interval, leading to cardiac arrhythmia such as torsades de pointes. There is no specific antidote for known diphenhydramine toxicity, but anticholinergic syndrome has been treated with physostigmine for severe delirium or tachycardia. Benzodiazepines may be given to reduce the likelihood of psychosis, agitation, and seizures in people susceptible to these symptoms.
Interactions
Alcohol can increase the drowsiness caused by diphenhydramine.
Pharmacology
Pharmacodynamics
Diphenhydramine acts primarily as an inverted agonist of histamine H 1 . It is a member of the class of ethanolamine an antihistaminergic agent. By reversing the effects of histamine on the capillaries, it can reduce the intensity of allergy symptoms. It also crosses the blood-brain barrier and in reverse destroys the centralized H 1 receptors. Its effect on the central receptor << sub> 1 causes sleepiness.
Like many other first-generation antihistamines, diphenhydramine is also a potent antimuscarinic (competitive antagonist acetylcholine muscarinic receptor) and, thus, at high doses can cause anticholinergic syndrome. The utility of diphenhydramine as an antiparkinson agent is the result of blocking properties of muscarinic acetylcholine receptors in the brain.
Diphenhydramine also acts as an inhibitor of the intracellular sodium channel, which is responsible for its action as a local anesthetic. Diphenhydramine has also been shown to inhibit serotonin reuptake. It has been shown to be the potential for analgesia induced by morphine, but not by endogenous opioids, in mice. This drug has also been found to act as a histamine inhibitor of N-methyltransferase (HNMT).
Pharmacokinetics
Diphenhydramine oral bioavailability is in the range of 40% to 60%, and peak plasma concentrations occur about 2 to 3 hours after administration. The main route of metabolism is two successive demethylations of tertiary amines. The resulting primary amine is then oxidized to carboxylic acid. The elimination half-life of diphenhydramine has not been fully explained, but appears to range between 2.4 and 9.3 hours in healthy adults. A 1985 pharmacokinetic antihistamine review found that the elimination half-life of diphenhydramine ranged between 3.4 and 9.3 hours in five studies, with an average elimination half-life of 4.3 hours. A 1990 study found that half-life of diphenhydramine elimination was 5.4 hours in children, 9.2 hours in young adults, and 13.5 hours in the elderly.
Chemistry
Diphenhydramine is a diphenylmethane derivative. The analogy to diphenhydramine includes orphenadrine, anticholinergics, nephopam, analgesics, and tofenacin, antidepressants. Selective serotonin reuptake inhibitors (SSRIs) of fluoxetine antidepressants are also near analogues of diphenhydramine.
Detection in body fluids
Diphenhydramine can be quantified in blood, plasma, or serum. Gas chromatography with mass spectrometry (GC-MS) can be used with ionization of electrons in full scan mode as a screening test. GC-MS or GC-NDP can be used for quantification. Rapid urine drug screening using immunoassays based on the principle of competitive binding can show false positive methadone results for people taking diphenhydramine. Quantification can be used to monitor therapy, confirm the diagnosis of poisoning in hospitalized people, provide evidence in driving disorders, or assist in investigation of death.
History
Diphenhydramine was discovered in 1943 by George Rieveschl, a former professor at the University of Cincinnati. In 1946, it became the first prescription antihistamine approved by the US FDA.
In the 1960s diphenhydramine was found to inhibit the reuptake of serotonin neurotransmitters. These findings led to the search for suitable antidepressants with the same structure and fewer side effects, culminating in the discovery of fluoxetine (Prozac), selective serotonin reuptake inhibitors (SSRIs). Similar previous searches have led to the synthesis of the first SSRI, zimelidine, from brompheniramine, as well as antihistamines.
Society and culture
Diphenhydramine is sometimes used recreatively as an opiate potentiator. Diphenhydramine is considered to have limited potential abuse in the United States due to the profile of potentially serious side effects and limited euphoria effects, and not controlled substances. Since 2002, the US FDA has mandated special labeling warnings against the use of some products containing diphenhydramine. In some jurisdictions, diphenhydramine is often present in postmortem specimens collected during sudden infant death investigations; the drug can play a role in this incident.
Diphenhydramine is a prohibited and controlled substance in the Republic of Zambia, and tourists are advised not to take medicine into the country. Some Americans have been arrested by the Zambia Drug Enforcement Commission for having Benadryl and other over-the-counter medicines containing diphenhydramine.
Use of recreation
Although diphenhydramine is widely used and is generally considered safe, many cases of abuse and addiction have been documented. Because the drugs are cheap and sold freely in most countries, teenagers who do not have access to illegal drugs are particularly at risk. People with mental health problems - especially those with schizophrenia - are also susceptible to substance abuse, given themselves in large doses to treat extrapyramidal symptoms caused by antipsychotic use.
Recreational users report the calming effect, mild euphoria, and hallucinations as the desired effect of the drug. Studies have shown that antimuscarinic agents, such as diphenhydramine, "may have antidepressant properties and mood enhancement." A study conducted on adult males with a history of sedative abuse found that subjects given high doses (400mg) of diphenhydramine reported a desire to take the drug again, although also reported negative effects, such as difficulty concentrating, confusion, tremors, and blurred vision.
Name
Diphenhydramine is marketed under the trade name Benadryl by McNeil Consumer Healthcare in the US, Canada and South Africa. Trade names in other countries include Dimedrol, Daedalon, and Nytol. It is also available as a generic drug.
Procter & amp; Gamble markets an over-the-counter formulation of diphenhydramine as a sleep aid under the ZzzQuil brand. By 2014, this product has annual sales of more than $ 120 million and has a 29.3% share of the $ 411 million sleep aid market category.
References
Further reading
External links
- Recipe Information at drugs.com
Source of the article : Wikipedia
0 Comments