Class: Chemotherapy

Generic Name: Thioguanine (thye-oh-GWO-neen), 6-TG, 6-Thioguanine, 2-Amino-6-Mercaptopurine
Trade Name: Tabloid®

How is this drug used? Thioguanine is FDA approved for the treatment of acute nonlymphocytic leukemias. Although thioguanine is one of several agents with activity in the treatment of the chronic phase of chronic myelogenous leukemia, more objective responses are observed with Myleran® (busulfan), and therefore busulfan is usually regarded as the preferred drug.  It is important for patients to remember that physicians have the ability to prescribe medication for conditions other than those for which the drug has been approved by the FDA. Patients who have received a prescription of this drug for a condition other than which it is approved may wish to discuss this issue with their physician.
What is the mechanism of action? Thioguanine belongs to a class of drugs called antimetabolites. Antimetabolites produce their anti-cancer effects by inhibiting the ability of a cell to produce or repair DNA, thereby making the cell unable to replicate or repair itself and ultimately causing cellular death.

How is thioguanine given (administered)? Thioguanine is given by mouth, in the form of a tablet and the dose depends on several factors, including the condition being treated, the size of the patient, the particular regimen being used and the overall health of the patient.

How are patients monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with thioguanine.  Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver.  Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy.

Patients are also at an increased risk for the development of a condition called tumor lysis syndrome in which electrolyte and metabolic disturbances occur.  Tumor lysis syndrome can be prevented if managed aggressively at the beginning of treatment.  Blood tests will measure levels of electrolyte and metabolic products, and patients should contact their healthcare provider if they experience symptoms such as nausea and vomiting, shortness of breath, an irregular heartbeat, clouding of urine, lethargy and/or joint discomfort.

Patients will also be monitored for an uncommon, yet potentially serious condition called veno-occlusive liver disease (VOD), a condition affecting the liver that may progress to affect other organs. If patients experience pain in the upper right quadrant of their abdomen, rapid weight gain, yellowing of the skin or eyes, or swelling of the hands, feet, face or abdomen, they should contact their healthcare provider immediately.

What are the common (occur in 30% or more of patients) side effects of treatment with thioguanine?

• Low white blood cell levels – increases risk of infection
• Low red blood cell levels – increases risk of anemia
• Low platelet levels – increases risk of bleeding

What are the less common (occur in 10% to 29% of patients) side effects of treatment with thioguanine?

• Loss of appetite
• Changes in liver function tests, liver damage
• Nausea or vomiting
• Mouth sores

This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.

Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.

What can patients do to help alleviate or prevent discomfort and side effects?

• Pay careful attention to the physician’s instructions and inform the physician of any side effects.
• Maintain adequate rest and nutrition.
• Wear sunscreen and protective clothing and try to minimize sun exposure.
• Drink plenty of fluids. (Patients should ask their physician about the amount of liquid to consume during a day.)
• If possible, patients should avoid large crowds or persons who are sick or not feeling well, as this drug may leave some patients susceptible to infection.
• Wash hands often to reduce the risk of infection.
• Avoid activities that may cause injury or bruising.
• Use a soft toothbrush and an electric razor to prevent cuts on the mouth or skin.
• Eat small meals frequently to help alleviate nausea.
• Use a soft toothbrush and an electric razor to prevent cuts on the mouth or skin.
• For mouth sores, patients should rinse their mouth three times a day with a salt and soda solution (8 ounces of water mixed with ½ to 1 tsp baking soda and/or ½ to 1 tsp salt) and brush their teeth with a soft toothbrush to help prevent the development of mouth sores.

Are there any special precautions patients should be aware of before starting treatment?

• Patients should inform their physician if they are pregnant, breastfeeding or planning a family in the near future. This drug may cause birth defects. It is important to use some kind of birth control while undergoing treatment. Also, patients may want to talk to their physician if they are considering having children in the future, since some drugs may cause fertility problems.
• It is important that patients inform their physician of any pre-existing conditions (chicken pox, heart disease, kidney disease, liver disease, lung disease, etc.) as they may worsen with this drug.
• Patients should inform their physician of any other medication they are taking (whether prescription or over-the-counter, including vitamins, herbs, etc.) as they may interfere with treatment.
• Patients should check with their physician before starting any new drug or nutritional supplement.
• Patients should inform their physician of any known drug or food allergies or any reactions to medications they have experienced in the past.
• If an oral dose is missed, do not double up on doses.  Patients should contact their doctor in this event.
• Keep tablets out of reach of children and return to the pharmacy for safe disposal if treatment is terminated.

When should patients notify their physician?

• Pain in the upper right quadrant of their abdomen
• Sudden weight gain
• Swelling of the hands, feet abdomen , face or ankles
• Signs of tumor lysis syndrome:  nausea and vomiting, shortness of breath, an irregular heartbeat, clouding of urine, lethargy and/or joint discomfort
• Flu or cold-like symptoms: fever, chills, sore throat, cough
• Signs of infection: redness, swelling, pus, tenderness, painful or frequent urination
• Persistent or severe fatigue
• Unexplained or excessive bleeding (nosebleeds, bruising, black tarry stools, blood in the urine, etc.)
• Yellowing of the skin or eyes
• Persistant or severe nausea or vomiting
• Persistant or servere diarrhea
• Mouth sores
• Skin rash

What is a package insert?

A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers.  A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.

Copyright © 2010 CancerConnect Last updated 07/10.

Important Limitations of Use

The information provided above on the drug you have selected is provided for your information only and is not a substitute for consultation with an appropriate medical doctor. We are providing this information solely as a courtesy and, as such, it is in no way a recommendation as to the safety, efficacy or appropriateness of any particular drug, regimen, dosing schedule for any particular cancer, condition or patient nor is it in any way to be considered medical advice. Patients should discuss the appropriateness of a particular drug or chemotherapy regimen with their physician.

As with any printed reference, the use of particular drugs, regimens and drug dosages may become out-of-date over time, since new information may have been published and become generally accepted after the latest update to this printed information. Please keep in mind that health care professionals are fully responsible for practicing within current standards, avoiding use of outdated regimens, employing good clinical judgment in selecting drugs and/or regimens, in calculating doses for individual patients, and verifying all dosage calculations.

DISCLAIMER OF WARRANTIES

CANCERCONSULTANTS.COM SPECIFICALLY DISCLAIMS AND EXCLUDES ALL EXPRESSED OR IMPLIED WARRANTIES, INCLUDING ANY IMPLIED WARRANTIES AS TO QUALITY, ACCURACY (INCLUDING TYPOGRAPHICAL ERRORS), MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE OF THE INFORMATION CONTAINED HEREIN.  CANCERCONSULTANTS.COM DISCLAIMS ALL LIABILITY OR DAMAGES ARISING FROM ANY USE OF THE INFORMATION.

The prescribing physician is solely responsible for making all decisions relating to appropriate patient care including, but not limited to, drugs, regimens, dose, schedule, and any supportive care.