Verteporfin (trade name Visudyne), a

benzoporphyrin Porphyrins ( ) are heterocyclic, macrocyclic, organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (). In vertebrates, an essential member of the porphyrin group is heme, wh ...

derivative, is a

medication Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...

used as a

photosensitizer Photosensitizers are light absorbers that alter the course of a photochemical reaction. They usually are catalysts. They can function by many mechanisms; sometimes they abstract an electron from the substrate, and sometimes they abstract a hydro ...

for

photodynamic therapy Photodynamic therapy (PDT) is a form of phototherapy involving light and a photosensitizing chemical substance used in conjunction with molecular oxygen to elicit cell death ( phototoxicity). PDT is used in treating acne, wet age-related macula ...

to eliminate the abnormal

blood vessel Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...

s in the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

associated with conditions such as the wet form of

macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred vision, blurred or vision loss, no vision in the center of the visual field. Early on there are often no sym ...

. Verteporfin accumulates in these abnormal blood vessels and, when stimulated by nonthermal red light with a

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

of 689 nm in the presence of

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

, produces highly reactive short-lived singlet oxygen and other reactive oxygen radicals, resulting in local damage to the

endothelium The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the r ...

and blockage of the vessels.Verteporfin Verteporfin is also used

off-label Off-label use is the use of pharmaceutical drugs for an unapproved indication (medicine), indication or in an unapproved age group, dose (biochemistry), dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) ca ...

for the treatment of

central serous retinopathy Central serous chorioretinopathy (CSC or CSCR), also known as central serous retinopathy (CSR), is an eye disease that causes visual impairment, often temporary, usually in one eye. When the disorder is active it is characterized by leakage of f ...

Administration

Verteporfin is usually injected

intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...

ly into the largest arm vein. It is injected at a dose of 6 mg/m2 and light-activated. It is usually given 15 minutes before laser treatment. This dose can be repeated 4 times per year.

Contraindications

Porphyria Porphyria ( or ) is a group of disorders in which substances called porphyrins build up in the body, adversely affecting the skin or nervous system. The types that affect the nervous system are also known as Porphyria#Acute porphyrias, acute p ...

: Patients with porphyria should not receive verteporfin due to the risk of exacerbating this condition.

Hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes Imm ...

: Patients with known hypersensitivity to verteprofin or any ingredients used in it's formulation should avoid use.

Side effects

Most common side effects are blurred vision, headache, and local effects at the injection site. Also,

photosensitivity Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicit ...

; it is strictly advised to avoid exposure to sunlight and unscreened lighting until 48 hours after verteporfin administration. Dogs and rats have been treated with inactivated daily doses 32–70 times higher than the dose advised for humans. The 4 weeks of treatment resulted in mild extravascular hemolysis and hematopoiesis in the animals.

Light-activated cytotoxicity

Used by itself, the clinical recommended dose for verteporfin is not

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of dr ...

to human tissue. Though under light activation, in the presence of oxygen, it can form cytotoxic agents inside the tissue. The agents form when the porphyrin absorbs enough light to generate a reactive but short-lived singlet oxygen. The brief singlet oxygen can micro damage biological structures, leading to a local vascular occlusion.

Interactions

Verteporfin is known to interact with the herbal remedy

feverfew ''Tanacetum parthenium'', known as feverfew, is a flowering plant in the daisy family, Asteraceae. It may be grown as an ornament, and may be identified by its synonyms, ''Chrysanthemum parthenium'' and ''Pyrethrum parthenium''. Having its ...

(''Tanacetum parthenium''), the latter of which seems to act as an antagonist to verteporfin for unknown reasons. Taking the two substances simultaneously is inadvisable. Verteporfin does not appear to be metabolized by

Cytochrome P450 Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for examp ...

enzymes, therefore not affecting

metabolism of other drugs.

Shortages

In May 2020, a low manufacturing capacity caused disruption. This affected the usage of verteporfin among providers and patients in Europe. The EMA expected normal manufacturing to return by the first quarter 2022.

Off-label use

Verteporfin may be used off-label for treating central serous retinopathy and is experimentally applied to reduce scarring in hair transplantations.

References

External links

* {{Intracellular chemotherapeutic agents Photosensitizing agents Ophthalmology drugs Drugs developed by Novartis