الفهرس 
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Abstract
The prophyrias are inherited or acquired disorders of specific enzymes in the heme biosynthetic pathway. These disorders are caused by partial deficiencies of one of the eight enzymes involved in heme production. Clinically, the porphyrias can be divided into acute porphyrias and non-acute porphyrias. The significans of the porphyrias to anaesthetist is that some of hepatic porphyrias are exacerbated by certain lipophilic drugs and produce acute neurological disturbances involving central, peripheral sensory and lTIotor, and autonomic nervous system disturbances. Acute attacks of porphyria may be precipitated by anaesthetic drugs, surgery, pregnancy and factors that are imposed routinely perioperatively such as fasting, infection, stress and steroids. The key to uneventful anaestheria for porphyric patients is the avoidance of precipitating factors. Premedication is important, as psychologic stress alone has reported to precipitate crises. Narcotics are safe in porphyria with exception of pentazocine, midazolam used safely. Induction of anaesthesia is carried out safely by propofol, ketamine and etomidate may be used.