How Do Topical Antineoplastics Work?

Topical antineoplastics are a class of drugs used on the skin to treat precancerous and cancerous skin growths, symptoms of actinic or solar keratosis (most common precancer that forms on skin damaged by chronic exposure to ultraviolet rays from the sun characterized by flat, scaly, or crusted lesions), and superficial basal cell carcinoma (a type of skin cancer that begins in the basal cells—a type of cell within the skin responsible for the production of new skin cells).

Topical antineoplastics are cytotoxic agents and toxic to certain cancer and precancerous cells. They are pyrimidine analogs (antimetabolites that interfere with nucleic acid synthesis) that irreversibly bind within a cell to thymidylate synthetase which prevents the incorporation of uracil into nuclear RNA that eventually destroys abnormal cancer cells.

Topical antineoplastics are available as a solution and a cream to be applied on the affected skin typically twice a day. They belong to a class of medications known as “antimetabolites” that work by blocking the growth of abnormal cells that causes precancerous and cancerous skin growths.

Topical antineoplastics are used to treat conditions such as:

• Actinic or solar keratosis (rough spots caused by long-term sun exposure)
• Superficial basal cell carcinoma (a type of skin cancer)

Some of the common side effects include:

• Diarrhea
• Rash
• Photosensitivity 
• Headache
• Redness/rash/pain/burning/itching/stinging/tingling at the application site 
• Skin irritation/dryness/swelling/tenderness or changes in skin color at the application site 
• Eye irritation
• Abnormal taste in the mouth

Other rare side effects include:

• Hair loss
• Insomnia 
• Blisters/pus/ulcers at the application site
• New or changed skin growths
• Thrombocytopenia (low blood platelet count)
• Allergic contact dermatitis (skin develops an allergic reaction after being exposed to a foreign substance)
• Hyperpigmentation (a harmless condition in which patches of skin become darker in color than the normal surrounding skin)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of topical antineoplastics include:

• Carac
• Efudex
• Fluoroplex
• Fluorouracil topical
• Ingenol mebutate topical
• Picato
• Tolak