Promethazine drugs

Since many of the uses of antihistamines involve conditions such as rashes, which should be treatable by local application, there is some rationale for developing drugs for topical use. The known side effects of antihistamines could in principle be avoided if the drug were functionalized so as to avoid systemic absorption. The known poor absorption of quaternary salts make such derivatives attractive for nonabsorbable antihistamines for topical use. Thus, reaction of the well-known anti his-taminic drug promethazine (104) with methyl chloride leads... 

The FT-Raman spectra of a range of drugs (theophylline, indomethacin, diclofenac, and promethazine) in several polymers (sodium alginate, hydroxy-propylmethylcellulose, and polyethylene glycol) have been obtained [56,57]. In these studies, the linearity of response of Raman scattering to species concentration was exploited to analyze diclofenac at concentrations of 0.01-6.0% w/w... 

Chlorpromazine, prochlorperazine, promethazine, methylprednisolone, lorazepam, metoclopramide, dexamethasone, or dronabinol may be used for adult patients. Around the clock dosing should be considered. The choice of specific agent should based on patient specific factors, including potential for adverse drug reactions, and cost. SSRIs are effective for breakthrough nausea and vomiting but they are not superior to the less expensive antiemetics above. 

Show how you would prepare 12 promethazine hydrochloride suppositories containing 20 mg of the drug in each suppository. Assume that you are required to use cocoa butter and that the displacement value of promethazine hydrochloride is 2.5. 

Promethazine employed as a preanesthetic calming drug by Laborit. 

There are also known cases of drug enantiomers that possess completely different therapeutic properties. The (+)-2/ ,35 -stereoisomer of propoxyphene (dextropropoxyphene) is marketed as an analgesic agent, whereas its enantiomer ( )-(25, 3/ )-propoxyphene (levopropoxyphene) is available as an effective anti-tussive agent [3]. The enantiomers of some chiral drugs are known to possess essentially identical qualitative and quantitative pharmacological activities, for example, the antihistamine promethazine, which is marketed as a racemate [5]. 

Neuroleptic malignant syndrome (NMS) A potentially fatal symptom complex sometimes referred to as NMS has been reported in association with promethazine alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status, and evidence of autonomic instability (eg, irregular pulse or blood pressure, tachycardia, diaphoresis, cardiac dysrhythmias). 

See the Antipsychotic Agents monograph for drug interactions that relate to promethazine. 

Drug/Lab test interactions Diagnostic pregnancy tests based on hCG may result in false-negative or false-positive interpretations in patients on promethazine. 

XX Zhang, F Hong, WB Chang, YX Ci, YH Ye. Enantiomeric separation of promethazine and D,L-a-amino-/3-[4-(l,2-dihydro-2-oxo-quinoline)] propionic acid drugs by capillary zone electrophoresis using albumins as chiral selectors. Anal Chim Acta 392 175-181, 1999. 

Other drugs Acetazolamide, acetosulfone, acetylcysteine, acitretin, allopurinol, aminoglutehimide, benzaflbrate, brompheniramine, calcium dobe-silate, chloropheniramine, chlorpropamide, colchicine, deferiprone, dapsone, flutamide, glibenclamide, hydroxychloroquine, mebhydro-lin, meprobamate, metapyrilene, methazolamide, metochlopramide, prednisone, promethazine, retinoic acid, riluzole, ritodrine, tolbutamide, yohimbine... 

Several Hi histamine antagonists (e.g., diphenhydramine, promethazine, and hydroxyzine) have been used as sedative-hypnotics, since they produce some degree of sedation. While this sedation is usually considered a side effect of their antihistaminic activity, in some cases the sedation is sufficient to allow the drugs to be used in the treatment of anxiety and sleep disturbances. For these drugs, the anxiolytic properties are thought to be a direct consequence of their ability to produce sedation. 

Many of these drugs have effects that are not mediated by Hi-receptors (Table 38.2). The antimuscarinic activity of several first-generation Hj-blockers may account for their effectiveness in combating motion sickness and their limited ability to suppress parkinsonian symptoms. The phenothiazines have some capacity to block a-adrenoceptors, whereas cyproheptadine Periactin) is an antagonist at serotonin receptors. Diphenhydramine Benadryl), pyrilamine (Ryna), and promethazine Phen-ergan) are effective local anesthetics. Many second-generation antihistamines also have been found to inhibit the non-histamine-mediated release of various... 

Many Hj-receptor blocking drugs have sedative properties, and some have been used in over-the-counter sleep aids. The most widely used Hj-blocking drugs for sleep induction are diphenhydramine, promethazine, and pyrilamine. 

Majority of antihistaminic drugs produce variable degree of CNS depression i.e. sedation, drowsiness and sleep. Drugs like diphenhydramine, promethazine are potent sedatives and is often accompanied by inability to concentrate. 

Antimotion sickness effect Several Hj-antagonists have significant property in preventing motion sickness. This effect was first observed with drug, dimenhydrinate and subsequently with other drugs like diphenhydramine, promethazine and other piperazine derivatives. 

Motion sickness Drugs like promethazine, promethazine chlorotheophyl-linate, diphenhydramine, dimenhydri-nate, cyclizine and meclizine have value in prophylaxis of motion sickness. 

One common denominator of all antipsychotics is the biockade of centrai dopamine (DA) receptors. As a result, extrapyramidal reactions, particularly parkinsonian symptoms, are a major adverse effect of many of these drugs, as well as an important clue to their mechanism of action. True Parkinson s disease is caused by a DA deficiency in the nigrostriatal system. Further, crystallographic data have demonstrated that CPZ s molecular configuration is similar to that of DA, which could explain its ability to block this neurotransmitter s receptors. Drugs with similar structures that do not block DA receptors (e.g., promethazine, imipramine) do not have antipsychotic activity. Another example is the isomer of flupenthixol, which blocks DA receptors is an effective antipsychotic, but the isomer that does not is ineffective (7). The other family of dopamine receptors, D and Dg, have not yet been implicated in psychosis. 

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