Verteporfin

INTRODUCTION

Indications

Treatment of age-related macular degeneration in patients with predominantly classic subfoveal choroidal neovascularization.

Action

Verteporfin is activated by nonthermal red light in the presence of oxygen to form reactive oxygen radicals. The resultant compound produces local damage to neovascular epithelium and subsequent vessel occlusion. Therapeutic Effects: Improved visual acuity.

Adverse Reactions/Side Effects

CNS: headache, weakness. EENT: visual disturbances, cataracts, conjunctivitis/conjunctival injection, dry eyes, ocular itching, severe vision loss, subconjunctival/subretinal/vitreous hemorrhage. Derm: photosensitivity. Local: injection-site reactions, including extravasation and rashes. MS: back pain (during infusion). Misc: fever, flu-like syndrome.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess any back pain, especially during or immediately after drug infusion. Try to determine if pain is drug-induced rather than caused by musculoskeletal pathology.

• Monitor IV injection site for pain, swelling, rash, or other local symptoms. Report prolonged or excessive injection site reactions to the physician.

Interventions

• Causes photosensitivity; avoid use of UV treatments for at least 5 days after drug infusion. Advise patient to avoid direct sunlight and wear protective clothing when outdoors.

Patient/Client-Related Instruction

• Instruct patient to report any vision disturbances, eye irritation, or loss of vision.

• Instruct patient to report other troublesome side effects such as severe or prolonged headache, fever, flu-like syndrome, or weakness.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.

Distribution: Transported by lipoproteins.

Metabolism and Excretion: Small amount of metabolism by the liver and plasma esterases; elimination is primarily fecal. Verteporfin in skin is inactivated by photobleaching from ambient indoor lighting.

Half-life: 5–6 hr.

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Porphyria; Exposure to direct sunlight.

Use Cautiously in: Moderate/severe hepatic impairment; Pregnancy, lactation or children (safety not established).

Interactions

Drug-Drug: Calcium channel blockers, polymyxin B, or radiation therapy may ↑ the rate of uptake by the vascular epithelium. Concurrent use of other photosensitizing agents, including thiazide diuretics, sulfonylureas, phenothiazines, sulfonamides or tetracyclines, may ↑ the risk of skin photosensitivity reactions. Dimethyl sulfoxide, beta-carotene, alcohol, formate, and mannitol may ↓ the activity of verteporfin.

Route/Dosage

IV (Adults): 6 mg/m² infused over 10 min, followed by appropriate laser light delivery initiated 15 min after the start of the infusion.