Verteporfin

Indications

Verteporfin is used for: Neovascular age-related macular degeneration

Adult Dose

Intravenous Photosensitiser in the photodynamic therapy of neovascular age-related macular degeneration Adult: 6 mg/m2 by infusion over 10 min, followed by activation using a laser tuned to a wavelength of 689 nm 15 min after the start of the infusion. Recommended light dose is 50J/cm2, given over 83 sec. Repeat every 3 mth for recurrent choroidal neovascular leakage. Hepatic impairment: Biliary obstruction; moderate to severe impairment: use with caution as no studies done.

Child Dose

Renal Dose

Administration

After IV infusion, eyedrops are used to numb eye Approximately 15 min after infusion & no later than 5 min after eyedrop application, a special ophthalmic lens is placed over eye Next the cold laser light spot-sized to match treatment area is applied

Contra Indications

Porphyria; lactation.

Precautions

Moderate to severe hepatic disorders; biliary disorders. Pregnancy. Use the largest arm vein possible (e.g. antecubital) especially in elderly and avoid small veins in the back of the hand. Stop infusion if extravasation occurs and protect extravasation area from direct light and apply cold compresses. Patient to be under close monitoring during verteporfin infusion and exercise caution when general anaesthesia is considered. Avoid exposure of unprotected skin, eyes or other body organs to direct sunlight or bright indoor light for 5 days after treatment. Protect all parts of skin and eyes by wearing protective clothing and dark sunglasses (sunscreens are ineffective) if going outdoors in daylight is necessary. Exposure to ambient indoor light is encouraged as it helps in gradual inactivation of any remaining drug.

Pregnancy-Lactation

Pregnancy Category: C Lactation: Distributed in milk; not recommended

Interactions

Increased rate of verteporfin uptake by the vascular endothelium with calcium channel blockers, polymyxin B or radiation therapy. Increased photosensitivity with photosensitizing agents (e.g. tetracyclines, sulfonamides, phenothiazines, sulfonylurea hypoglycaemic agents, thiazide diuretics and griseofulvin). Decreased verteporfin efficacy with compounds that quench active oxygen species or scavenge radicals e.g. dimethyl sulfoxide, betacarotene, ethanol, formate and mannitol. Decreased verteporfin efficacy with drugs that decrease clotting, vasoconstriction or platelet aggregation e.g. thromboxane A2 inhibitors. Anaesthetics may cause haemodynamic effects.

Adverse Effects

Side effects of Verteporfin : Visual disturbances; severe vision loss with or without subretinal or vitreous bleeding; inj site reactions; nausea; photosensitivity; asthenia; cataracts; blepharitis; conjunctivitis; dry eyes; ocular itching; flu-like syndrome; atrial fibrillation; hypertension; peripheral vascular disorder; varicose veins; eczema; constipation; GI cancers; fever; lachrymation disorder; hypersensitivity reactions; increased LFT.

Mechanism of Action

Verteporfin, when activated by low-intensity nonheat-generating laser light at a wavelength corresponding to its absorption peak, generates highly reactive, short-lived singlet O2 and reactive O2 radicals that cause local damage to neovascular endothelium, resulting in vessel occlusion. It appears to accumulate preferentially in the neovasculature e.g. choroidal neovasculature.