Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Lanvis (Thioguanine).

Anemia: Lanvis (Thioguanine) may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible

Blood clotting: Lanvis (Thioguanine) can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. Tell your doctor of any signs that your blood is not clotting as quickly as usual. Such symptoms may include black and tarry stools, blood in the urine, easy bruising, or cuts that won't stop bleeding.

Gout: Lanvis (Thioguanine) increases the blood levels of uric acid, which may increase the risk of gout.

Infection: As well as killing cancer cells, Lanvis (Thioguanine) can reduce the number of cells that fight infection in the body (white blood cells). Avoid contact with people with contagious infections and tell your doctor if you begin to notice signs of an infection, such as fever or chills.

Liver function: Lanvis (Thioguanine) can reduce liver function and can cause liver damage. If you have liver problems, discuss with your doctor how Lanvis (Thioguanine) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Lanvis (Thioguanine), and whether any special monitoring is needed. Your doctor will order blood tests for your liver function regularly while you are taking Lanvis (Thioguanine).

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Pregnancy: There is a possibility of birth defect if either the man or woman is using Lanvis (Thioguanine) at the time of conception. As well, it may harm the baby if used during pregnancy. Effective birth control should be practiced while using Lanvis (Thioguanine).

Lanvis (Thioguanine) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Lanvis (Thioguanine), contact your doctor immediately.

Breast-feeding: It is not known whether Lanvis (Thioguanine) passes into breast milk. Because of the risks associated with Lanvis (Thioguanine), a decision should be made to stop breast-feeding or to stop the medication, taking into account the importance of the medication to the mother.