Phenothiazines photosensitivity with

Photosensitivity Because photosensitivity has been reported (rarely with thioridazine), undue exposure to the sun should be avoided during phenothiazine treatment. 

Phenothiazine [58-37-7] (thiodiphenylamine) is used orally against intestinal nematodes of ruminants and horses. It is used with occasional gastrointestinal upset, hemolytic processes, and photosensitivity. It is used routinely at low concentrations on horse farms to suppress the egg production of intestinal parasites (strongyles) and thus limit pasture contamination and transmission (4). 

Drug-induced photosensitivity reactions are divided into phototoxicity (a nonimmunologic reaction) and photoallergic reactions (an immunologic reaction). The latter form is far less common. Medications associated with photosensitivity reactions include fluoroquinolones, nonsteroidal antiinflammatory drugs, phenothiazines, antihistamines, estrogens, progestins, sulfonamides, sulfonylureas, thiazide diuretics, and tricyclic antidepressants. 

In a review of photopatch-testing in 2390 patients with rashes that were confined to sun-exposed areas, about 70% of 4374 positive reactions were classified as photo-induced reactions, of which 222 (5%) were photoaUergic reactions (6). NSAIDs, disinfectants, and phenothiazines were the main photoallergens. Photosensitive reactions to antimicrobial drugs, including topical agents, have been reviewed (7). 

Rashes due to thiazides are common but are only very occasionally severe and disabling (SEDA-11, 198). A state of chronic photosensitivity can persist for many years after drug withdrawal and is difficult to treat (23) it can mimic contact dermatitis, and there can be crossreactivity with sulfonamides and phenothiazines. Patients who develop photosensitivity to thiazides should never take these drugs again. 

In the recent decay, there is a considerable interest in making green photopolymerizations using photosensitizers. One way to obtain nontoxic polymers through sensitization is to copolymerize compounds that can behave either as a photosensitizer or monomer with different monomers [113]. Another way is to polymerize these monomeric photosensitizers and afterward subject them to sensitize the polymerization of convenient monomers. In both ways, nontoxic and odorless polymers can be obtained after polymerization. Compounds introducing phenothiazine moiety and their polymeric analogs were found the display high efficiency in PCP of vinyl ethers and epoxides. 

Several dyes with photosensitizing properties have been reported including phenon-axine, phenothiazine (methylene blue) (Figure 21) and acridine orange. Thiazine dyes and acridine were the first agents used in antiviral PDT. 

The phenothiazine drugs listed in Table 7 are all capable of cross-reacting with the phenothiazine antihistamines, and all of these compounds are potential photosensitizers (Lewis and Sawicky 1955). Often a photoallergic reaction occurs in combination with the allergic eczematous contact dermatitis. The systemic administration of the phenothiazine drugs shown in Table 7 may produce an eczematous contact dermatitis medicamentosa in individuals sensitized by such topical exposure. Cross-reactions readily take place between these phenothiazines and the related antihistamines (Mitchell and Ongley 1972). 

This phenothiazine with sedative properties is used in human medicines and has induced contact dermatitis in nurses or in those working in the pharmaceutical industry. It is also used in veterinary medicine to avoid mortality of pigs during transportation. It is a sensitizer and a photosensitizer. 

A wide assortment of electron transfer photosensitizers for diaryiiodonium salts have been described in the journal and patent literature. Among these are polynuclear aromatic hydrocarbons with three or more rings such as anthracene, alkoxyanthracenes, pyrene, and perylene heterocyclic compounds of low basicity such as carbazoles " and phenothiazines aromatic ketones such as benzophenone, Michler s ketone, and thioxanthone and substituted thiox-anthones coumarins phenanthrene-9,10-quinone Mannich bases and (dimethylamino)benzylidyne compounds. In addition, the use of dyes such as eosine, acridine orange, acridine red, and benzoflavin has been employed to provide photosensitization in the visible region of the spectrum. 

Because they have lower oxidation potentials, diaryliodonium salts are more easily photosensitized than triarylsulfonium salts. Thus, while diaryliodonium salts are photosensitized by a variety of aryl ketones, condensed ring aromatic hydrocarbons and dyes, useful photosensitizers for triarylsulfonium salts, are limited to those photoinitiators with high triplet energies and low oxidation potentials. Condensed ring aromatic hydrocarbons such as anthracene, rubrene, coronene, perylene and certain heterocyclic compounds as phenothiazine derivatives meet these requirements. 

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