Phototoxic properties of neuroleptic drugs.
BACKGROUND
Photo-induced eruptions are well-known adverse effects of some neuroleptic drugs, particularly chlorpromazine.


OBJECTIVE
By a photohemolysis test we assessed in vitro the phototoxic properties of 12 phenothiazines (chlorpromazine, dixyrazine, fluphenazine, levomepromazine, perazine, perphenazine, promazine, promethazine, prothipendyl, thioridazine, trifluoperazine, triflupromazine) and 5 thioxanthenes (chlorprothixene, clopenthixol, flupenthixol, thiothixene, zuclopenthixol).


METHODS
Human erythrocytes from 3 donors were incubated with the compounds and irradiated with light sources rich in UVA or UVB, respectively. Doses were up to 100 J/cm2 UVA or up to 1,600 mJ/cm2 UVB. Photo-induced hemolysis was calculated as percentage of complete hemolysis.


RESULTS
Photo-induced hemolysis >10% due to radiation rich in UVA was found with chlorpromazine (maximal median: 98%), dixyrazine (100%), fluphenazine (84%), perazine (100%), perphenazine (100%), promazine (16%), promethazine (25%), prothipendyl (96%), trifluoperazine (100%), triflupromazine (76%), chlorprothixene (100%) and thiothixene (31%). UVB-rich radiation induced hemolysis only with chlorpromazine (73%), dixyrazine (45%) and perazine (60%).


CONCLUSIONS
Most neuroleptics are strongly phototoxic in vitro indicating a potential risk for photo-induced reactions also to occur in patients treated with these drugs.
Eberlein-König
B
B
Dermatologische Klinik und Poliklinik der Ludwig-Maximilians-Universität München, Deutschland.
Bindl
A
A
Przybilla
B
B
D014150:Antipsychotic Agents / Q000009:adverse effects*; D002746:Chlorpromazine / Q000009:adverse effects; D002749:Chlorprothixene / Q000009:adverse effects; D003006:Clopenthixol / Q000009:adverse effects; D017484:Dermatitis, Phototoxic / Q000209:etiology*; D003875:Drug Eruptions / Q000209:etiology*; D004912:Erythrocytes / Q000187:drug effects; D005475:Flupenthixol / Q000009:adverse effects; D005476:Fluphenazine / Q000009:adverse effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008728:Methotrimeprazine / Q000009:adverse effects; D010464:Perazine / Q000009:adverse effects; D010546:Perphenazine / Q000009:adverse effects; D010640:Phenothiazines / Q000009:adverse effects; D011395:Promazine / Q000009:adverse effects; D011398:Promethazine / Q000009:adverse effects; D011829:Radiation Dosage; D013843:Thiazines / Q000009:adverse effects; D013881:Thioridazine / Q000009:adverse effects; D013888:Thiothixene / Q000009:adverse effects; D014268:Trifluoperazine / Q000009:adverse effects; D014273:Triflupromazine / Q000009:adverse effects; D014466:Ultraviolet Rays / Q000009:adverse effects
D014150:Antipsychotic Agents; D010640:Phenothiazines; D013843:Thiazines; D014268:Trifluoperazine; C069248:prothipendyl; D013888:Thiothixene; C012950:dixyrazine; D010464:Perazine; D003006:Clopenthixol; D008728:Methotrimeprazine; D002749:Chlorprothixene; D005475:Flupenthixol; D011398:Promethazine; D010546:Perphenazine; D013881:Thioridazine; D011395:Promazine; D014273:Triflupromazine; D005476:Fluphenazine; D002746:Chlorpromazine