Phototoxicity demeclocycline

Phototoxic reactions are most frequent with demeclocycline, and occur less frequently with the other tetracyclines minocycline is least likely to cause phototoxic reactions. 

Phototoxicity Phototoxicity, for example, severe sunburn, occurs when the patient receiving a tetracycline is exposed to sun or ultraviolet rays. This toxicity is encountered most frequently with tetracycline, doxycydine, and demeclocycline [dem e kloe SYE kleen],... 

D. Phototoxicity is encountered most frequently with demeclocycline and doxycycline. 

Demeclocycline lacks the C-6-methyl of tetracycline and is produced by a genetically altered strain of Streptomyces aureofaciens. Because it is a secondary alcohol, it is more chemically stable than tetracycline against dehydration. Food and milk co-consumption decrease absorption by half, although it is 60 to 80% absorbed by fasting adults. It is the tetracycline most highly associated with phototoxicity and has been shown to produce dose-dependent, reversible diabetes insipidus with extended use. 

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