Administration of oral activated charcoal in variegate porphyria results in a paradoxical clinical and biochemical deterioration.
BACKGROUND
Porphyrinogens are the obligate intracellular precursors of haem. These compounds are, however, unstable and are easily oxidized to the corresponding porphyrins, which are the form in which they are usually measured in the laboratory. A substantial enterohepatic cycling of porphyrins has been shown. Administration of oral activated charcoal, by interrupting this cycle, may reduce plasma and urine porphyrin levels in patients with some forms of porphyria. The effect of charcoal in subjects with variegate porphyria (VP) has not been reported.


OBJECTIVE
To determine the clinical and biochemical effects of the administration of oral activated charcoal in patients with VP.


METHODS
Oral activated charcoal was administered to eight subjects with VP. Clinical activity was assessed by skin lesion counts fortnightly for 6 weeks, 6 weeks after cessation of therapy, and during a subsequent 6-week control period during which no charcoal was taken. Urine and plasma porphyrins and urine precursors were measured by standard techniques.


RESULTS
Treatment resulted in a significant increase in skin disease, urine and plasma porphyrins.


CONCLUSIONS
Oral charcoal administration results in a paradoxical aggravation of VP, suggesting a complex and as yet undefined interaction of hepatic porphyrin metabolism and bowel porphyrin reabsorption. Oral sorbents should not be prescribed to subjects with VP.
Hift
R J
RJ
MRC/UCT Liver Research Centre and Department of Medicine, University of Cape Town, Medical School, Observatory 7925, South Africa. rjh@liver.uct.ac.za
Todd
G
G
Meissner
P N
PN
Kirsch
R E
RE
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000622:Aminolevulinic Acid / Q000097:blood / Q000652:urine; D000704:Analysis of Variance; D002606:Charcoal / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D011162:Porphobilinogen / Q000097:blood / Q000652:urine; D017094:Porphyrias, Hepatic / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011166:Porphyrins / Q000097:blood / Q000652:urine; D011446:Prospective Studies; D013019:South Africa; D017211:Treatment Failure
D011166:Porphyrins; D002606:Charcoal; D011162:Porphobilinogen; D000622:Aminolevulinic Acid