How Do Thymidylate Synthetase Inhibitors Work?

Thymidylate synthetase inhibitors are a class of drugs used to treat the adenocarcinoma of the colon (large intestine), rectum, breast, pancreas, and stomach.

Thymidylate synthetase inhibitors are folate-based potential anticancer chemotherapy medications and a nucleoside analog that work by inhibiting the enzyme thymidylate synthetase (a critical enzyme for DNA replication and cell growth) that further suppresses DNA synthesis.

Thymidylate synthetase inhibitors are administered via intravenous route.

Thymidylate synthetase inhibitors work in the following ways:

• They are a potential anticancer chemotherapy medication that work by inhibiting the enzyme thymidylate synthase.
• This inhibition further prevents the methylation of C5 of deoxyuridine monophosphate, thereby inhibiting the synthesis of deoxythymidine monophosphate.
• Because of this effect, tumor cells cannot undergo DNA synthesis, thus promoting cell death.

Thymidylate synthetase inhibitors are used to treat conditions such as:

Adenocarcinoma of:

• Colon
• Rectum 
• Stomach
• Breast
• Pancreas

Some of the common side effects include:

• Nausea
• Vomiting
• Diarrhea
• Headache
• Dry skin
• Photosensitivity (extreme sensitivity to UV rays from the sun)
• Loss of appetite
• Tiredness/weakness
• Mouth sores

Other rare side effects include:

• Dizziness 
• Fatigue 
• Hair loss
• Anemia (low red blood cell count)
• Thrombocytopenia (low blood platelet count)
• Cardiotoxicity (a condition when the heart muscles are damaged)
• Hyperammonemia encephalopathy (an unusual complication characterized by a decreasing level of consciousness, focal neurological deficits, cognitive slowing, vomiting, drowsiness, and lethargy)
• Neurologic toxicity (damage to the brain or peripheral nervous system)
• Palmar-plantar erythrodysesthesia (also known as hand-foot syndrome characterized by redness, swelling, and pain on the palms of the hands and/or the soles of the feet)
• Myelosuppression (a decrease in bone marrow activity, resulting in reduced production of blood cells)
• Altered mental status
• Confusion
• Visual disturbances
• Increased risk of elevated international normalized ratio (a blood test to analyze blood clotting)
• Increased lacrimation (increased secretion of tears)
• Photophobia (increased sensitivity and aversion to light)
• Thrombophlebitis (inflammation of a vein caused by a blood clot)
• Epistaxis (bleeding from the nose)
• Nystagmus (an involuntary, rapid, and repetitive movement of the eyes)

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 thymidylate synthetase inhibitors include:

• 5-Fluorouracil
• Raltitrexed
• Capecitabine