Photochemical Production of Oxy Radicals
Robert A. Greenwald in CRC Handbook of Methods for Oxygen Radical Research, 2018
Many molecules have been shown to be photodynamic sensitizers, including various acridines, porphyrins, phenothiazines, quinones, flavins, and metal derivatives such as ruthenium bipyridyl. An activated sensitizer can react directly with other molecules to produce free radicals by removal of an electron or of hydrogen, or the sensitizer can react with molecular oxygen in aqueous solution to produce activated forms of oxygen, particularly singlet oxygen. Another route to activated oxygen species lies in photoreduction of the molecule in the presence of a suitable hydrogen donor, followed by reaction of the reduced molecule (either one- or two-electron) with dioxygen with transfer of an electron to yield superoxide radical anions.
Nausea and vomiting
Alan Galbraith, Shane Bullock, Elizabeth Manias, Barry Hunt, Ann Richards in Fundamentals of Pharmacology, 2007
Phenothiazines These drugs are dealt with more fully in Chapter 33. They are dopamine antagonists and act centrally by blocking the CTZ. The only phenothiazine without appreciable antiemetic properties is thioridazine. In practice, only prochlorperazine is used commonly. These drugs are not of much use in the treatment of nausea due to motion sickness (except promethazine, which is an antihistamine phenothiazine).
Antipsychotics: pharmacology
Kathy J Aitchison, Karena Meehan, Robin M Murray in First Episode Psychosis, 2022
The first drug to be prescribed for the treatment of psychosis was chlorpromazine. In the early 1990s the situation changed with the marketing of clozapine in most Western nations as the first antipsychotic with a significantly different profile, both in animal and human studies. Conventional antipsychotics of other chemical groups tend to resemble the piperazine phenothiazines. Clozapine has a broad spectrum of receptor affinities. The atypical antipsychotics are metabolized by polymorphic cytochromes. Olanzapine is also metabolized significantly by N-glucuronidation and by the flavin-monooxygenase system, which means that its metabolism is less dependent on the polymorphic and inducible cytochrome systems. Serotonergic theories of schizophrenia stretch back to the evidence that many hallucinogens, and possibly endogenous hallucinogens, act on serotonin receptors.
Enhanced beneficial effects of mild hypothermia by phenothiazine drugs in stroke therapy
Published in Neurological Research, 2015
Shimeng Liu, Xiaokun Geng, Brian Forreider, Yao Xiao, Qingtao Kong, Yuchuan Ding, Xunming Ji
Objectives: Hypothermia is a well-recognised and effective neuroprotectant because of its depressive effect on metabolism. However, its application in focal ischaemic stroke is limited by delayed onset, prolonged duration, the need for extensive medical and nursing efforts and significant complications. This study combined mild hypothermia with phenothiazine drugs to enhance its neuroprotective effects, thus potentially avoiding side effects. Methods: Fifty-four male Sprague-Dawley rats were induced with a 2-hour right middle cerebral artery (MCA) occlusion using an intraluminal filament. Five groups were tested: the stroke group without treatment (anal temperature 37.8–38.3°C), the mild hypothermia group (anal temperature 35.0°C), the drugs group (1 mg/kg chlorpromazine and 1 mg/kg promethazine, anal temperature at 37.8–38.3°C), combination therapy with the mild hypothermia and drugs group and the normal control group (anal temperature 37.8–38.3°C). The treatments immediately followed reperfusion. The extent of brain injury was evaluated by infarct volume and behaviour performance. Results: The combination treatment of mild hypothermia with phenothiazine drugs demonstrated salient and significant (P
Phenothiazines as anti-tubercular agents: mechanistic insights and clinical implications
Published in Expert Opinion on Investigational Drugs, 2011
Introduction: Tuberculosis (TB) chemotherapy has been rendered ineffective by the emergence of multi-drug resistant (MDR), extensively drug resistant (XDR) and totally drug resistant strains reinforcing the need for the development of new drugs as a global health priority. Reconsidering phenothiazines for the improvement of TB chemotherapy seems to be a rational option especially in view of their role as inhibitors of type II NADH dehydrogenase, a key component of respiratory chain of Mycobacterium tuberculosis, thus raising the speculation that they can be effective against latent TB as well. Areas covered: This article offers a detailed description of the chemotherapeutic efficacy of phenothiazine compounds against susceptible, drug resistant and latent TB. Furthermore, their clinical implications and molecular mechanisms of action have been reviewed extensively. Expert Opinion: Phenothiazines are currently being evaluated for the treatment of TB and have been shown to be effective against M. tuberculosis through a number of in vitro, ex vivo and in vivo studies. In addition, recent clinical studies have implicated their role in the treatment of MDR/XDR TB also. Therefore, phenothiazines, particularly thioridazine, hold great potential to be considered as safe and effective antimycobacterial agents in near future.
Ocular side effects of phenothiazines
Published in Clinical and Experimental Optometry, 1991
Rolene Scott, Geoffrey T Cunningham, Jenny M Puddle, Jeremy D Klinger, Robert J Jacobs
It has been shown that prolonged usage of phenothiazine drugs causes tissue changes in the eye. Such changes were evaluated in 19 long‐term psychiatric patients who had taken phenothiazines over periods ranging from five to 32 years to assess whether decreased contrast sensitivity function and colour vision anomalies could be used as indicators of ocular tissue change. Using Vistech gratings, contrast sensitivity was found to be below normal at 6,12 and 18 cycles per degree in 45 per cent, 16 per cent and 39 per cent of the eyes respectively. The Farnsworth Dichotomous Panel D15 test revealed colour vision anomalies in more than half the eyes. However, linear regression analysis showed no systematic relationship between the results of either test and the degree of ocular tissue changes observed.
Related Knowledge Centers
- Adverse Drug Reaction
- Anthelmintic
- Antipsychotic
- Promethazine
- Extrapyramidal Symptoms
- Antiemetic
- Antihistamine