Thioguanine (Oral)

Thioguanine is a prescription medication that treats certain types of cancer.


Thioguanine comes in tablet form and is manufactured under the US brand Tabloid. This medication treats certain kinds of cancer. The medicine inhibits the growth and development of cancer cells, which are ultimately destroyed.

A prescription for thioguanine must be obtained before the patient takes the medicine. A doctor will ensure a patient experiences less side effects from interactions that can occur from food or other medications.

It is important to note with this medication that healthy cells within the body could also be impacted by thioguanine. Impacts to healthy cells may cause effects that do not take place for a lengthy period of time - sometimes years or months after taking the medication. The patient should discuss the benefits and risks with their doctor prior to taking thioguanine, as it is only accessible with a doctor's recommendation.

Conditions treated

  • acute myeloid leukemia

Type of medicine

  • Antimetabolite

Side effects

Thioguanine occasionally causes vomiting and an overall feeling of nausea. Nevertheless, it is imperative that you continue taking this medication, despite the ill feelings. Consult your physician prior to discontinuing this medication. Your doctor can give you ideas for reducing unpleasant effects.

If the patient vomits soon after having a dose of thioguanine, consult the physician whether or not the dose should be taken again or should be omitted until the next dose.

Medications that are similar to thioguanine can occasionally cause side effects to occur that are unwanted. These side affects can include blood problems and are detailed below. Due to the way this medication impacts the body, there is a small chance that they could cause additional side effects that may not be identified until years or months after the medication was used. A delayed side effect of this medication includes specific types of cancer, including leukemia. Be sure to discuss this side effect with your physician.

Not all of the following side effects will take place, but if they do happen, they could require medical care.

Consult your physician right away if side effects take place.

More common side effects (immediate medical care required)

  • Back/side pain (lower back)
  • Bleeding/bruising (unusual occurences)
  • Cough/hoarseness
  • Fever/chills
  • Red spots on skin
  • Stool irregularity (black, tarry, or accompanied by blood)
  • Urine difficulty, pain, or irregularity (accompanied by blood)

Less common side effects (medical care required as soon as possible)

  • Joint pain
  • Swelling (feet/lower legs)
  • Unsteadiness while walking

Rare side effects (medical care required as soon as possible)

  • Sores in/on mouth/lips
  • Yellowing of the skin or eyes

Additional side effects (frequency not known)

  • Abdomen bloating
  • Abdomen pain/fullness (upper right portion)
  • Appetite loss
  • Back/side pain (lower back)
  • Breath odor unpleasant
  • Breath shortness
  • Chest discomfort or pain
  • Cough/hoarseness
  • Coughing out blood
  • Fainting
  • Fatigue
  • Headache
  • Hives
  • Itching
  • Nausea
  • Rash
  • Skin paleness
  • Sore throat
  • Spots purple or red in color inside of the nose or mouth
  • Stomach or abdominal pain
  • Stool irregularities (light-colored)
  • Swollen glands
  • Tiredness/weakness (unusual)
  • Urine darkness
  • Vomiting
  • Vomiting blood
  • Weight gain

Certain side effects may not require medical care. These effects can disappear on their own during the course of treatment as the body is able to adjust more to the medication. The patient's health care provider will be able to discuss ways to reduce or prevent certain side effects. Speak with your doctor if any of the following side effects occur or are especially troublesome, or if there are any questions regarding them.

Less common side effects (medical care not required)

  • Appetite loss
  • Vomiting and nausea
  • Skin itching or rash
  • Diarrhea

Additional side effects can occur for certain patients. If you observe side effects that are not on these lists, consult your healthcare professional for direction.

Speak with your doctor for information and advice regarding side effects. The FDA also accepts reports of side effects, and they can be reached at 1-800-FDA-1088.


Individual patients will likely need a specific dose of thioguanine, which is why patients may receive different dosage instructions. Monitor the doctor's directions on the medication carefully. Average dosing data will be listed below, but is intended for informational use only. Never adjust a dose without approval from your doctor, as the strength of the medicine will be changed.

The number of doses taken throughout the day will also influence the effectiveness of the medication. Similarly, the time between doses and the medical issue will also determine how successful thioguanine is.

Only take thioguanine according to the directions by your physician. Do not take a higher or lower amount than what is prescribed. Do not take thioguanine more frequently than prescribed.

The prescribed dose is unique for each patient and must be cautiously worked out by your doctor. Too much of thioguanine can increase the occurrence of side effects, and too little medication may not be of aid for your condition.

Your physician may recommend drinking extra liquids while taking thioguanine so that more urine will be passed. This is beneficial as kidney problems can be avoided and the kidneys can remain healthy.

Missed dose

Once the patient discovers a dose has been overlooked, the medicine needs to be taken right away, unless the planned next dose is close, in which case the first dose can remain skipped and dosage can resume as normal afterwards. Never double dose thioguanine. Consult your pharmacist or doctor for additional instructions.


Drug interactions

Under certain circumstances, medications should never be combined if it can be avoided. During other circumstances, multiple medications can be combined, even though there may be a chance of potential interaction. Your physician may adjust the amount or frequency of one of the medications if your unique circumstances allow you to combine multiple prescriptions. If your unique situation allows for you to combine prescriptions, be sure you are taking each one at the correct time, and be sure not to mix them. Consult your doctor for help in regards to planning your medication taking times.

Patients must always inform the doctor of any additional medications they are already taking. The following medications could cause an increased occurrence of various side effects, but the combination of both medications could prove to be the most optimal treatment plan.

  • Busulfan

Other interactions

Some prescriptions cannot be used while eating or around the time of eating, due to the interactions that have the potential to occur. Tobacco or alcohol use could trigger negative interactions. Discuss these concerns with your physician, and understand the interactions of thioguanine with food, tobacco, or alcohol.

Other medical problems

If the patient has any additional medical issues, this medication could be affected. Disclose all medical problems to your physician, especially:

  • Chickenpox (recent exposure included)
  • Gout (history of)
  • Infection - immunity can be reduced when taking thioguanine
  • Kidney disease - increased side effects due to the body's reduced extraction of thioguanine
  • Kidney stones (history of) - concentrations of uric acid (the cause of kidney stones) within the body could be increased
  • Liver disease - increased side effects due to the body's reduced extraction of thioguanine
  • Shingles (herpes zoster) - severe risk of disease spreading to other body parts
  • Thiopurine methyltransferase deficiency (TPMT) - patients could be more sensitive to side effects and receive a reduced dose
  • Tumors - should not be used if previously treated with thioguanine. The use of thioguanine will not likely help reduce the size of the tumor for those who have been previously treated.


Patients taking thioguanine should see a doctor regularly for routine checkups. The medical professional should review progress of the medication, monitor the patient's reaction, and ensure there are no negative side effects occurring. These meetings will ensure undesirable outcomes are minimized.

Myelosuppression can be a result of cancer treatments; it is the most common negative reaction to thioguanine. Myelosuppression is an illness in which the movement of the bone marrow is reduced, which causes there to be fewer red and white blood cells in the body, as well as fewer platelets. When unfavorable effects are observed, medication times and doses need to be changed accordingly, to counteract life-threatening cytopenias.

Patients who are taking thioguanine frequently get hyperuricemia, as a result of rapid cell lysis supplementing the antineoplastic effect. Hydration can immensely improve negative side effects and the alkalinization of urine.

Patients who are taking multiple drugs have reported that intestinal necrosis and perforation have been experienced while taking thioguanine.

Negative reactions that occur less often include stomatitis, anorexia, vomiting, and nausea.


Immunizations should be avoided during a patient is undergoing treatment for thioguanine. They should not have any immunizations after treatment until the physician approves it. Thioguanine could reduce the resistance of the body to infection and, as a result, the patient could end up contracting the infection that the immunization is intended to prevent or counteract.

Others in your household should not receive or have recently received the oral polio vaccine, either, due to there being a chance that the polio virus could be passed to the patient. Do not spend time near other people who have recently gotten the oral polio vaccine. Maintain distance between them and ensure you are not spending time with them in the same room for lengthy periods of time. A protective facemask can be helpful for those who are not able to follow these precautions.

Thioguanine can temporarily reduce the total amount of white blood cells in the body, which increases chance of receiving an infection. The total count of platelets can also be reduced, and these are essential for appropriate blood clotting. There are several precautions that can be taken when the blood count reaches an extremely low number to lower the risk of bleeding or infection:

  • Avoid individuals who have infections, if possible. Consult your physician right away if you suspect that you are contracting an infection, or if you experience chills, fever, hoarseness, cough, side pain, lower back pain, difficulty, or pain when urinating.
  • Consult your physician right away if you suspect any atypical bruising or bleeding, tarry, black stools, urine in stools or blood or red dots resembling pinpoints on the skin.
  • Take extra caution if you use a normal toothbrush, toothpick, or dental floss. There may be other methods to cleaning the teeth and gums that your doctor, nurse, or dentist may recommend. Consult your physician if you need to have any kind of dental work performed.
  • Where possible, don't touch the inside of your nose or your eyes. Only do this is if your hands have just been cleaned beforehand with soap and water, and nothing else has been touched in the interim.
  • Take caution not to cut yourself while using scissors or other sharp objects, including fingernail or toenail cutters and safety razors.
  • Contact sports should be avoided, along with additional situations where injury or bruising is likely.


The doctor should be alerted if there are any atypical or uncommon allergic reactions by the patient to the medicine, which may include skin rash, hives, or additional irregularities. Cease use immediately and contact a physician if there are any allergic reactions to this medication.

The physician must know which allergies the patient has prior to prescribing this medication. For example, the allergies could be to dyes, preservatives, foods, or animals. Ensure the directions on the package are read thoroughly, as these can contain important information regarding ingredients that could cause an allergic reaction.

Specific demographic use


Children are additionally sensitive to thioguanine. Take caution - this can raise the likelihood that toxicity of the liver can occur during treatment. Thioguanine is not safe and effective for children.


Many prescriptions have not been tested in the geriatric population. The way the medication works for older people is unknown, as it may not work in a similar manner for younger adults. Different issues or side effects could occur for older people. No information is available regarding the use of this medication for the elderly.


It has been confirmed that thioguanine does pose a risk to the fetus when a pregnant woman takes the medication. However, when involved in a position that is life threatening or when living with a severe disease that could prevent the woman's ability to carry the baby to full term, a patient may value the benefits of thioguanine over the potential risk.


It is important to consider both the pros and cons of incorporating thioguanine into a diet when a women is breastfeeding. There have not been any adequate studies conducted to determine if this medication is effective and safe for both mother and baby during breastfeeding.


This medication must be stored out of children's reach.

Store this medication at room temperature in a container that is closed. It should not be near direct light, freezing temperatures, or heat.

Thioguanine should be disposed of when it reaches the expiration date, within six weeks of opening, or when it is no longer needed.


Thioguanine is a potent medication and should be avoided unless an individual has been diagnosed with acute non lymphocytic leukemia. The doctor involved in prescribing the medication should also be experienced in analyzing reactions to chemotherapy.

As there are many side effects that can take place while taking this prescription, work closely to determine the amount of thioguanine that is right for you. This medicine also impairs the health of the healthy cells within the body, which is why it is important to discuss all of the pros and cons of thioguanine with your doctor. There are several warnings and precautions patients should take when on this prescription. Patients must stay regular in their check up appointments with their doctors in order to ensure they are doing everything they can to combat the disease.

Last Reviewed:
December 25, 2017
Last Updated:
April 05, 2018
Content Source: