In patients with preexisting lung and/or heart disease, these medications should be monitored closely or not prescribed.The future of anesthetic care involves the simultaneous administration of several drugs including IV medications and inhaled anesthetics.Diphenhydramine can be quantified in blood, plasma, or serum.This discovery led to a search for viable antidepressants with similar structures and fewer side effects, culminating in the invention of fluoxetine (Prozac), a selective serotonin reuptake inhibitor (SSRI). FDA has required special labeling warning against use of multiple products that contain diphenhydramine.The drug is an ingredient in several products sold as sleep aids, either alone or in combination with other ingredients such as acetaminophen (paracetamol) in Tylenol PM or ibuprofen in Advil PM.Diphenhydramine can cause minor psychological dependence. Topical diphenhydramine is sometimes used especially for people in hospice.
Some cases that require sedation may also necessitate the use of analgesics to decrease pain associated with a procedure or test.
Several levels of evidence strongly indicate diphenhydramine (similar to chlorpheniramine) can block the delayed rectifier potassium channel and, as a consequence, prolong the QT interval, leading to cardiac arrhythmias such as torsades de pointes. Like many other first-generation antihistamines, diphenhydramine is also a potent antimuscarinic (a competitive antagonist of muscarinic acetylcholine receptors) and, as such, at high doses can cause anticholinergic syndrome.
The utility of diphenhydramine as an antiparkinson agent is the result of its blocking properties on the muscarinic acetylcholine receptors in the brain.
These are used to relieve itching and have the advantage of causing fewer systemic effects (e.g., drowsiness) than oral forms.
Because of its sedative properties, diphenhydramine is widely used in nonprescription sleep aids for insomnia.
Diphenhydramine is marketed under the trade name Benadryl by Mc Neil Consumer Healthcare in the U. Trade names in other countries include Dimedrol, Daedalon, and Nytol. Procter & Gamble markets an over-the-counter formulation of diphenhydramine as a sleep aid under the brand Zzz Quil.