Porphyria

 

Phlebitis with or without leukocytes and with or without mild pyrexia has occured after
administration of hematin through small arm veins.

There has been one report of coagulopathy.
The patient exhibited prolonged prothrombin time, partial thromboplastin time, thrombocytopenia,
mild hypofibronogenemia, mild elevation of fibrin split products and a 10% fall in hematocrit
 

Hypersenstivit to hemin; porphyia cutanea tarda

Special precautions:
Neutronal damage- attacks of porphyria may progress to irreversible neutronal damage.
Renal effects- reversible renal shutdown has been observed.

Monitoring-
Drug effect will be demonstarted by a decreas in urinary concentration  of one or more of the following  compounds-
ALA (delta -aminolevulinic acid)
UPG (uroporphyrinogen )
PGG ( porohobilinogen coproporphyrin )

Neuronal damage-
Clinical benefit depends on prompt administration . Attacks of prorphyria may progree to irreversible neuronal damage
Hemin therapy is intended to prevent an atack fromraeching the critical stage of neuronal
degeneration . This agent is not effctive in reapiring neuronal damage.

Renal effects- reversaible renal shutdown has ben observed where an excessive hemin dose  (12.2mg/kg) was administered in a single infusion>Oliguria had increased nitrogen retention occured  although the patient  remained unsympotomatic. No worsening of renal function has been seen with the use of recommened dosages.

Diagnostic tests- before beginning therapy diagnose the presence of axute porphyria using the  following criteria- presence of clinical symptoms and positive Watson-Schwartz or Hoesch test.

Warnings-
Pregnancy- Safety for use during pregnancy has not been established. Use only when needed.

Lactation- Safety for use in nursing mother has not been established.

Children- Safety and efficacy for use in children have not been established.

   

 

Indication:

Porphyria Dosage:

For IV use only. Use a large arm vein or a central venous catheter to avoid phlebitis. Because reconstituted hemin is not transparent, any undissolved particulate matter is difficult to see; therfore terminal filtration through a sterile 0.45micron or smaller filter is recommended.

Overdosage-

Symptoms Reversible renal shutdown has been observed in a case where an excessive hermin dose (12mg/kg) was administrered in a single infusion Treatment Treatment in this case consisted of ethacrynic acid and mannitol

Pharmacology:

Hemin for injection is an enzyme inhibitor derived from procesed red blood cells. It was also prevously known as hematin. Porphyrias are rare metabolic disorders that, as a group, represent disturbances of heme synthesis and are differentiated on the basis of specific enzymatic defects.

Pharmacokinetics:

Following IV admin of hematin in non-jaundiced patients, an increase in fecal urobilinogen can be observed, which is roughly proportional to the amount of hematin administered. This suggests an enterohepatic pathway as at least one route of elimination.

Pregnancy:

Use only when clearly needed and when the potential benefits outweigh the potential hazards to the fetus.

Lactation:

Safety for use in a nursing mother has not been established. Children- Safety and efficacy for use in children have not been established.