Medical term:

porfimer


porfimer

 [por´fĭ-mer″]
a light-activated antineoplastic agent related to porphyrin, used as the sodium salt in the treatment of esophageal carcinoma and non–small cell lung carcinoma; administered intravenously.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

porfimer

(pore-fim-er) ,

Photofrin

(trade name)

Classification

Therapeutic: antineoplastics
Pharmacologic: photosensitizers
Pregnancy Category: C

Indications

Part of photodynamic therapy (PDT) for:
  • Esophageal cancer that has completely or partially obstructed the esophagus and cannot be treated with Nd:YAG laser therapy,
  • Reduction of obstruction and palliation of symptoms in patients with completely or partially obstructive endobronchial non-small lung cancer,
  • Microinvasive endobronchial non-small cell lung cancer when surgery or radiation are not options,
  • High grade dysplasia due to Barrett's esophagus in patients who are unable to have esophagectomy.

Action

Porfimer is retained by the tumor, which is then treated with a laser light. When porfimer absorbs the light, a photochemical reaction occurs, causing cellular damage.
Thromboxane A is also produced, causing additional local tumor necrosis.

Therapeutic effects

Shrinkage of esophageal or endobronchial tumors.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.
Distribution: Retained for a longer period by tumors, skin, and reticuloendothelial tissue.
Protein Binding: 90%.
Metabolism and Excretion: Unknown.
Half-life: 410 hr (first dose); 725 hr (2nd dose).

Time/action profile (antitumor effect)

ROUTEONSETPEAKDURATION
IVrapid†unknownunknown
†After laser light treatment

Contraindications/Precautions

Contraindicated in: History of porphyria or hypersensitivity to porphyrins; Tracheobronchial or bronchoesophageal fistulas or tumors with potential to erode into a major blood vessel or the trachea; Not suitable for acute treatment of patients with severe respiratory distress due to obstructive endotrachial lesion; Tumors eroding into a major blood vessel; Esophageal or gastric varices, or esophageal ulcers >1 cm in diameter; Should not be used within 4 wk of radiation therapy.
Use Cautiously in: Direct sunlight or bright indoor light (photosensitivity will occur); Hepatic or renal impairment (may require more than 90 days of precautionary photosensitivity measures); Obstetric / Lactation / Pediatric: Pregnancy, lactation, or children (contraception should be practiced; safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • insomnia (most frequent)
  • anxiety
  • confusion
  • weakness

Respiratory

  • respiratory insufficiency (life-threatening)
  • dyspnea (most frequent)
  • mucositis reaction (most frequent)
  • pharyngitis (most frequent)
  • pleural effusion (most frequent)
  • pneumonia (most frequent)
  • cough
  • tracheoesophageal fistula

Cardiovascular

  • heart failure (life-threatening)
  • thromboembolic events (life-threatening)
  • atrial fibrillation
  • chest pain (most frequent)
  • edema
  • hypertension
  • hypotension
  • tachycardia

Gastrointestinal

  • esophageal rupture (life-threatening)
  • GI bleeding (life-threatening)
  • abdominal pain (most frequent)
  • constipation (most frequent)
  • esophageal stricture (most frequent)
  • nausea (most frequent)
  • vomiting (most frequent)
  • anorexia
  • diarrhea
  • dyspepsia
  • eructation
  • esophageal tumor bleeding

Dermatologic

  • photosensitivity (most frequent)

Fluid and Electrolyte

  • dehydration

Hematologic

  • anemia (most frequent)

Miscellaneous

  • fever (most frequent)
  • pain (most frequent)
  • moniliasis
  • urinary tract infection
  • weight loss

Interactions

Drug-Drug interaction

Photosensitizing effect may be ↑ by concurrent use of tetracyclines, sulfonamides, phenothiazines, sulfonylurea oral hypoglycemic agents, or thiazide diuretics.The effects of photodynamic therapy may be altered by calcium channel blockers, corticosteroids, ethanol, mannitol, dimethyl sulfoxide, beta carotene, vasoconstrictors, or agents that affect clotting.

Route/Dosage

Intravenous (Adults) 2 mg/kg followed 40–50 hr later by laser light therapy. A second session of laser light therapy may be given 96–120 hr after porfimer and may be preceded by gentle tumor débridement. Up to three treatments may be given, with a 30–day minimum interval between treatments.

Availability

Powder for injection (requires reconstitution): 75 mg/vial

Nursing implications

Nursing assessment

  • Assess patient for substernal chest pain after therapy. May result from an inflammatory response in the treatment area. May require opioid analgesics to relieve symptoms.
  • Before each new course of therapy, the patient should be examined for either bronchoesophageal or tracheoesophageal fistula.
  • Lab Test Considerations: May cause ↓ in hemoglobin and hematocrit as a result of tumor bleeding induced by photodynamic therapy.

Potential Nursing Diagnoses

Risk for injury (Adverse Reactions)

Implementation

  • Avoid contact with skin and eyes during preparation. Use of disposable gloves and eye covering is recommended. If exposure occurs, follow directions for preventing a photosensitivity reaction (see Patient/Family Teaching).
    • Porfimer spills may be wiped up with a damp cloth. Contaminated materials should be disposed in a polyethylene bag, following regulations for handling hazardous waste (see ).
  • Intravenous Administration
  • Diluent: Dilute 75–mg vial with 31.8 mL of D5W or 0.9% NaCl. Protect reconstituted solution from bright light and use immediately. Concentration: 2.5 mg/mL.
  • Rate: Administer over 3–5 min. If solution extravasates, protect injection site from bright light for 30 days.

Patient/Family Teaching

  • Instruct patient in precautions to prevent photosensitivity reactions. Precautions should be used for 30 days (90 days if patient has liver impairment). Avoid exposure of skin and eyes to direct sunlight and bright indoor light (dental or operating room lights, unshaded light bulbs at close proximity).
  • Porfimer is slowly and safely inactivated by ambient indoor light. Patients should avoid spending long periods in darkened rooms and should expose themselves to ambient indoor light.
  • Patients may test themselves for residual photosensitivity by exposing a small portion of skin to sunlight for 10 min. If erythema, blistering, or edema does not occur within 24 hr, patients may gradually increase their exposure to bright lights or sunlight. If a photosensitivity reaction occurs, patient should avoid exposure for an additional 2 wk, then retest skin. Do not use face for photosensitivity testing because skin around eyes may be more sensitive. Before traveling to geographic areas that have increased light, patients should retest their photosensitivity level.
  • Ultraviolet sunscreens offer no protection against a photosensitivity reaction because porfimer is activated by visible light.
  • Ocular sensitivity to sunlight, bright lights, or car headlights may occur. Patients should wear dark glasses that transmit <4% of white light when outside for approximately 30 days after administration of porfimer.
  • Advise patient to notify health care professional if ocular sensitivity, chest pain, respiratory distress, or esophageal strictures occur.

Evaluation/Desired Outcomes

  • Shrinkage of esophageal tumors.
Drug Guide, © 2015 Farlex and Partners

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