Low-dose oral chloroquine in the treatment of porphyria cutanea tarda

Abstract

Seven patients with porphyria cutanea tarda received a total of ten courses of low-dose oral chloroquine therapy (125 mg chloroquine phosphate twice weekly). Patients were treated for a mean 14.9 months during which time all went into clinical and biochemical remission. Relapse occurred in four patients on a total of six occasions after a mean 17 months. In four patients there was no relapse after a mean 47.3 months. There were no adverse side-effects from the treatment. Low-dose oral chloroquine therapy appears to be a safe, effective and convenient treatment for porphyria cutanea tarda, although relapses may occur requiring further therapy.

Porfiria cutânea tardia

“…120,121 chloroquine in antimalarial doses causes severe hepatotoxic reaction associated to intense uroporphynuria and photosensitization. 120 Low doses -125mg 117,122,123 or 250mg124 -twice a week, were successfully used in several reports. Chloroquine administration is followed by increased urine excretion of pophyrins 125 and slight increase in hepatic transaminases at the beginning of treatment.…”

“…127 Bullae and cutaneous fragility improve in approximately 6 months and the porphyrin excretion normalizes between six to 15 months. 117,122,124,127 It is recommended that treatment must not be interrupted until biochemical remission (urine URO < 100ìg/24h) is attained. 122 The duration of the remission period varies from 17 to 24 months.…”

“…117,122,124,127 It is recommended that treatment must not be interrupted until biochemical remission (urine URO < 100ìg/24h) is attained. 122 The duration of the remission period varies from 17 to 24 months. 122,127 Chloroquine is effective, however relapse occurs earlier than after phlebotomy.…”

“…122 The duration of the remission period varies from 17 to 24 months. 122,127 Chloroquine is effective, however relapse occurs earlier than after phlebotomy. 117 There are several hypotheses to explain the mechanism of action of chloroquine: (1) it chelates iron from hepatocytes, which is later eliminated; 128 (2) it reduces ALA-synthetase activity; 129 (3) it forms a complex with uroporphyrin, which is excreted by the liver through the bile, 130 but the model utilized is not comparable to human PCT 129 , and (4) it increases the excretion of porphyrins by means of exocytosis and has a porphyrinostatic effect, inhibiting porphyrin formation.…”

Dual Porphyria of Coexisting Variegata and Cutanea Tarda

“…While in porphyria cutanea tarda the mobilization and successive renal elimination of accumulated liver porphyrins by low-dose chloroquine treatment has become a successful therapy (7,22), in the case of dual variegate -cutanea tarda it should be considered that chloroquine sometimes induces acute porphyria manifestations (23). Therefore, chloroquine should either be omitted in these cases or, if the variegate is in a latent and stable phase (constantly normal urinary 5-aminolaevulinic acid and porphobilinogen levels), be applied under continuous clinical and pathobiochemical monitoring of urinary 5-aminolaevulinic acid, porphobilinogen and porphyrin excretion.…”