Ethanolamine antihistaminic

Benztropine mesylate (cogentin, others), biperiden (akineton), procycUdine (kemadrin), and trihexyphenidyl hydrochloride (artane, others) are tertiary-amine muscarinic receptor antagonists (together with the ethanolamine antihistamine diphenhydramine [benadryl, others]) that gain access to the CNS and can therefore be used when anticholinergics are indicated to treat parkinsonism and the extrapyramidal side effects of antipsychotic drugs (see Chapter 20). 

It is an ethanolamine antihistaminic agent belonging to the first-generation Hj-antagonist... 

The drug is an ethanolamine antihistamine agent having appreciable sedative pharmacologic activity and, generally, listed in OTC sleep aids. It also possesses significant anticholinergic activity. 

Hf and H Receptors. Histamine exerts its actions by binding to receptors on cell membranes. Two types of histamine receptors, the Hi and H2 receptors, are known specific agonists and antagonists exist for each of these receptors. Black et al. (55) differentiated H and H2 receptors with the compounds, 2-methylhistamine and 4 methylhistamine. 2-Methylhistamine is active on tissues with H receptors 4-methylhistamine is active on tissues with H2 receptors. Classical antihistaminic drugs were developed in the 1930 s these compounds block H but not H2 receptors. Among the clinically used H -blockers are derivatives of ethanolamine, ethylenediamine, alkylamine, piperazine and phenothiazine (32). These agents are valuable in the treatment of... 

Ethanolamines—(diphenhydramine was the prototypical agent in this group). Ethylenediamines, which were the first group of clinically effective Hj antihistamines developed, (pyrilamine). 

Iatrogenic Reactions broadly refer to any adverse reactions that are unintentionally produced by physicians in their patients. For example, one of the side effects of many antihistaminic preparations (Hj antagonists) such as ethanolamine derivatives (prototype diphenhydramine) is heavy sedation. Although sedation may be desirable for some patients, it may interfere with daytime activities, and this needs to be considered when prescribing such medications. Other antihistaminic preparations (also 11 antagonists) such as piperidine derivatives (prototypes terfenadine or astemizole) have no sedative properties (Figure 3.2). 

Liquid chromatography thermospray—mass spectrometry has been utilized to determine the identity and purity of taxol, solvent-induced degradation of cloxacillin [129], benzodiazepines, and ethanolamine-type antihistamines [130]. Electrospray LC-MS has been used for peptide mapping of the human growth hormone [131]. 

Of the systemic antihistamines, the ethanolamines, including diphenhydramine, have significant antimuscarinic activity. In addition, the antipsychotic agents, particularly the phenothiazines such as thioridazine (Mellaril), have well-dociunented anticholinergic properties. Therapeutic doses of tricyclic antidepressants, like amitriptyline hydrochloride (Elavil) and imipramine (Tofranil), produce significant anticholinergic actions and thus have the potential for ocular side effects. 

The early antihistamines. Hi histamine receptor antagonists, bore some structural resemblance to histamine and, like histamine, contained an ethylamine group. However, the structures of the many antihistamines that are available are disparate, and the traditional classification according to chemical structure (ethanolamine, ethy-lenediamine, alkylamine, piperazine, and phenothiazine) is outdated, since the second-generation antihistamines, such as terfenadine and astemizole, do not readily fit into the old classification system (2). 

This member of the ethanolamine series is characterized by a lung duration of action, with an activity that reaches a maximum in S to 7 hours and persists for 10 to 12 hours. It is well absorbed when administered orally, and it is excreted primarily in the urine. The side effects arc those usually encountered with this series of antihistamines. Clemastine is closely related to chlorphenoxomine, which is used for its central cholinergic-blocking activity. Therefore, it is not surprising that clemastine has significant antimuscarinic activity. 

Clinically important, potentially hazardous interactions with alcohol, antihistamines, ardeparin, argatroban, brompheniramine, buclizine, chlorpheniramine, dalteparin, danaparoid, dicumarol, enoxaparin, ethanolamine, heparin, imatinib, tinzaparin, warfarin... 

Clinically important, potentially hazardous interactions with alcohol, anticoagulants, antihistamines, betamethasone, brompheniramine, buclizine, buprenorphine, chlorpheniramine, darunavir, dasatinib, delavirdine, dexamethasone, dicumarol, ethanolamine, fesoterodine, fluconazole, flunisolide, fosamprenavir, hydrocortisone, imatinib, influenza vaccines, lacosamide, lapatinib, lopinavir, meperidine, methylprednisolone, midazolam, nilotinib, piracetam, pizotifen, prednisolone, prednisone, rivaroxaban, rufinamide, solifenacin, telithromycin, temsirolimus, teniposide, trabectedin, triamcinolone, warfarin... 

Ethanolamine-derivative H, antagonist antihistamines used to treat motion sickness include diphenhydramine HCl 12-(diphcnylmcthoxy)- V, V-dimethylethylamine hydrochloride C17H21NO HCI] and dimenhydrinate [8-chloro-3,7-dihydro-l,3-dimethyl-lH-purine-2,6-dione compound with... 

Drugs developed during the 1940s (e.g., pyrilamine and diphenhydramine) were marketed for the treatment of various allergic conditions such as urticaria and hay fever, for which they are still in use. Many additional drugs joined these two pioneering agents. Ultimately, five chemical classes of antihistamines evolved ethanolamine derivatives, eth-ylenediamines, alkylamines, piperazines, and phenothiazine and other polycyclics. Representative examples of each class are illustrated in Table 13-1. 

Which antihistamines are included in the ethanolamine class of drugs ... 

SAR of Buclizine. Importantly, buclizine-a member of the piperazine class of antihistaminics are very much structurally related to both the ethylenediamines as well as the benzyhydryl ethers of ethanolamines. Its structure essentially include the 2 carbon separation existing between the N-atoms, that forms a part of the piperazine ring. 

Some of the antihistamine (Hi)-receptor antagonists that can cross the blood-brain barrier are used for their hypnotic activity. The primary antihistamines used for their sedative effect are diphenhydramine and doxylamine, which belong to the ethanolamine class of antihistamines (see Chapter 37). Both drugs are sold without prescription. Sleep laboratory-controlled studies indicate that the antihistamines (Hi-receptor... 

Nitrogen-linked ethylenediamines Oxygen-linked ethanolamines Carbon-linked alkylamines Phenothiazine antihistamines Cyclizines (piperazines) Piperidines Miscellaneous... 

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