porfimernatrium

Porfimer sodium, commonly known by the brand name Photofrin, is a photosensitizing agent used in photodynamic therapy. It is a complex mixture of hematoporphyrin derivatives (HPD) and belongs to the class of porphyrin-based photosensitizers. After intravenous administration, it distributes in body tissues and tends to accumulate in malignant tissue to a greater extent than in normal tissue.

The therapeutic effect of porfimer sodium depends on light activation. When illuminated with light at a wavelength of approximately 630 nanometers (red light), the drug becomes excited and transfers energy to molecular oxygen to produce reactive oxygen species, including singlet oxygen. This leads to tumor cell death, vascular damage, and an inflammatory response that can contribute to antitumor activity.

The timing of light exposure relative to dosing varies by protocol, but activation typically occurs 24 to 96 hours after administration. Light delivery is lesion-specific and may be achieved endoscopically, interstitially, or externally, using sources capable of delivering red light around 630 nm. Dose and light fluence are carefully controlled to maximize tumor destruction while limiting damage to surrounding tissue.

Indications for porfimer sodium include photodynamic therapy for a range of neoplasms and selected premalignant or obstructive conditions, with use governed by local regulatory approvals. It is commonly employed for palliative treatment of certain airway or esophageal lesions and in selected head and neck cancers, among other sites.

Safety considerations include prolonged photosensitivity, necessitating avoidance of direct sunlight and bright indoor lighting for several weeks after treatment. Other adverse effects may include localized swelling or pain, nausea, and transient liver enzyme elevations. Patients are advised to follow clinician guidance on light protection and symptom monitoring.