Thioguanine

Registered South African indications:

• Acute myelocytic leukaemia
• Chronic myelocytic leukaemia

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Live vaccines must not be used on patients receiving thioguanine

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Hepatic impairment
• Thiopurine S-methyltransferase deficiency
• Mutated NUDT15 gene
• Myelosuppressive chemotherapy
• Lesch-Nyhan syndrome
• Exposure to sunlight and ultraviolet light 
• Lactose intolerance 
• Galactose intolerance
• Lapp lactase deficiency
• Glucose-galactose malabsorption

Forms avail. in SA and covered in this monograph: tab

Used for the treatment of

Acute myelocytic leukaemia
Chronic myelocytic leukaemia

Consult specialist for dosages and regimens

See adult dosage

Pregnancy

• Caution; not recommended
• Thioguanine should be avoided whenever possible during pregnancy, particularly during the first trimester
• Contraception in males and females: As with all cytotoxic chemotherapy, adequate contraceptive precautions must be advised when either partner is receiving thioguanine

Breastfeeding

• Caution; not recommended

Renal Impairment

• Caution; dose adjustment recommended

Hepatic Impairment

• Caution; dose adjustment recommended

Elderly

• No dose adjustment recommended

Gastrointestinal Disorders

• Stomatitis
• Gastrointestinal disorder
• Necrotising colitis

Hepatobiliary Disorders

• Venoocclusive liver disease
• Hyperbilirubinaemia
• Hepatomegaly
• Increased weight 
• Portal hypertension
• Increased hepatic enzymes
• Increased blood alkaline phosphatase 
• Increased gamma glutamyltransferase 
• Jaundice
• Portal fibrosis
• Nodular regenerative hyperplasia
• Peliosis hepatitis
• Venoocclusive liver disease
• Hepatic necrosis

Genitourinary Disorders

• Hyperuricosuria 
• Urate nephropathy

Musculoskeletal Disorders

• Hyperuricaemia

Skin and Subcutaneous Tissue Disorders

• Photosensitivity

Immune, Blood and Lymphatic System Disorders

• Bone marrow failure

• Live vaccines
• Other myelotoxic substances
• Radiation therapy
• Aminosalicylate derivatives

• Full blood count with differential
• Hepatic function

Thioguanine is a sulphydryl analogue of guanine and behaves as a purine antimetabolite. It is activated to its nucleotide, thioguanylic acid. Thioguanine metabolites inhibit de novo purine synthesis and purine nucleotide interconvertions. Thioguanine is also incorporated into nucleic acids and DNA (deoxyribonucleic acid) incorporation is claimed to contribute to the agent's cytotoxicity.

Tablet 40mg

• Lanvis (Pharmacare) originator