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Other information

Indication
Indicated in the treatment of esophageal cancer.

Pharmacology
Porfimer is a photosensitizing agent used in the photodynamic therapy (PDT) of tumors. Porfimer is indicated for the palliation of patients with completely obstructing esophageal cancer, or of patients with partially obstructing esophageal cancer who cannot be satisfactorily treated with Nd:YAG laser therapy, reduction of obstruction and palliation of symptoms in patients with completely or partially obstructing endobronchial nonsmall cell lung cancer (NSCLC), and the treatment of microinvasive endobronchial NSCLC in patients for whom surgery and radiotherapy are not indicated. The cytotoxic and antitumor actions of Porfimer are light and oxygen dependent. Tumor selectivity in treatment occurs through a combination of selective retention of Porfimer and selective delivery of light.

Mechanism Of Action
Cellular damage caused by Porfimer is a consequence of the propagation of radical reactions. Radical initiation may occur after Porfimer absorbs light to form a porphyrin excited state. Spin transfer from Porfimer to molecular oxygen may then generate singlet oxygen. Subsequent radical reactions can form superoxide and hydroxyl radicals. Tumor death also occurs through ischemic necrosis secondary to vascular occlusion that appears to be partly mediated by thromboxane A2 release.

Drug Category
Dermatologic Agents; Antivirals; Antineoplastic Agents; ATC:L01XD01

Brand Names/Synonyms
DHE; Dhp Ether; Dihematoporphyrin Ether; Photofrin; Porfimer; Porfimer Sodium

Dosage Forms
POWDER FOR SOLUTION

Absorption
Not Available

Interactions
Interactions for Porfimer:

There have been no formal interaction studies of PHOTOFRIN^® and any other drugs. However, it is possible that concomitant use of other photosensitizing agents (e.g., tetracyclines, sulfonamides, phenothiazines, sulfonylurea hypoglycemia agents, thiazide diuretics, and griseofulvin) could increase the photosensitivity reaction.

PHOTOFRIN^® PDT causes direct intracellular damage by initiating radical chain reactions that damage intracellular membranes and mitochondria. Tissue damage also results from ischemia secondary to vasoconstriction, platelet activation and aggregation and clotting. Research in animals and in cell culture has suggested that many drugs could influence the effects of PDT, possible examples of which are described below. There are no human data that support or rebut these possibilities.

Compounds that quench active oxygen species or scavenge radicals, such as dimethyl sufloxide, b-carotene, ethanol, formate and mannitol would be expected to decrease PDT activity. Preclinical data also suggest that tissue ischemia, allopurinol, calcium channel blockers and some prostaglandin synthesis inhibitors could interfere with PHOTOFRIN^® PDT. Drugs that decrease clotting, vasoconstriction or platelet aggregation, e.g., thromboxane A₂ inhibitors, could decrease the efficacy of PDT. Glucocorticoid hormones given before or concomitant with PDT may decrease the efficacy of the treatment.

Chemical IUPAC Name
Not Available

Chemical Formula
C68H74N8O11

Half Life
10-452 hours

Drug Type
Approved Drug

# Accession No
APRD00078

CAS Registry Number
87806-31-3