Overview
11 DESCRIPTION PANHEMATIN (hemin for injection) is an enzyme inhibitor derived from processed red blood cells. Hemin for injection was known previously as hematin. The term hematin has been used to describe the chemical reaction product of hemin and sodium carbonate solution. Hemin and hematin are iron containing metalloporphyrin complexes with either bound chloride or hydroxide ions,...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Heme acts to limit the hepatic and/or marrow synthesis of porphyrin. This action is likely due to the inhibition of δ-aminolevulinic acid synthetase, the enzyme which limits the rate of the porphyrin/heme biosynthetic pathway. The exact mechanism by which hematin produces symptomatic improvement in patients with acute episodes of the hepatic porphyrias has not been elucidated. PANHEMATIN therapy for the acute porphyrias is not curative. After discontinuation of PANHEMATIN treatment, symptoms generally return although in some cases remission is prolonged. Some neurological symptoms have improved weeks to months after therapy although little or no response was noted at the time of treatment. 12.
Indications
- 1 INDICATIONS AND USAGE PANHEMATIN is a hemin for injection indicated for the amelioration of recurrent attacks of acute intermittent porphyria temporally related to the menstrual cycle in susceptible women, after initial carbohydrate therapy is known or suspected to be inadequate. Limitations of Use • Before administering PANHEMATIN, consider an appropriate period of carbohydrate loading (i.e., 400 g glucose/day for 1 to 2 days) [ See Dosage and Administration ( 2.1 ) ]. • Attacks of porphyria may progress to a point where irreversible neuronal damage has occurred.
Common Doses
- 4 mg
- 6 mg
- 100 mL
- 7 mg
Dosage
2 DOSAGE AND ADMINISTRATION For intravenous infusion only. For intravenous infusion only. Dose ( 2.1 ) 1 to 4 mg/kg/day for 3 to 14 days based on the clinical signs. The standard dose in clinical practice is 3 to 4 mg/kg/day. Repeat dose in more severe cases no earlier than every 12 hours. Do not exceed 6 mg/kg in any 24 hour period. Administration ( 2.2 ) Use sterile 0.45 micron or smaller filter to remove any undissolved particulate matter. The dose may be administered directly from the vial over a period of at least 30 minutes. After the infusion, flush the vein with 100 mL of 0.9% NaCl. 2.
Contraindications
- 4 CONTRAINDICATIONS PANHEMATIN is contraindicated in patients with known hypersensitivity to this drug. Do not use in patients with known hypersensitivity to PANHEMATIN. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The most common adverse reactions (occurring in >1% of patients) are: headache, pyrexia, infusion site reactions, and phlebitis. Most common adverse reactions in >1% of patients are headache, pyrexia, infusion site reactions, and phlebitis. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Recordati Rare Diseases Inc. at 1-888-575-8344 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly...
Interactions
- 7 DRUG INTERACTIONS PANHEMATIN therapy is intended to limit the rate of porphyria/heme biosynthesis possibly by inhibiting the enzyme δ-aminolevulinic acid synthetase 1 (ALAS1) [See Clinical Pharmacology ( 12.1 )] . Most of the heme synthesized in liver is used for the production of cytochrome P450 (CYP) enzymes. Therefore, avoid CYP inducing drugs (such as estrogens, barbituric acid derivatives and steroid metabolites) while on PANHEMATIN therapy, because these drugs increase the activity of ALAS leading to induction of ALAS1 through a feedback mechanism.