What It Is and What It Treats
Imanix contains imatinib mesilate, the first molecularly
targeted anti-cancer therapy. It selectively inhibits the BCR-ABL tyrosine
kinase (the pathogenic kinase in CML), as well as KIT (CD117) and PDGFR
kinases, making it active across a range of malignancies driven by these
enzymes.
Indications:
· Chronic phase CML
(adults and paediatric patients)
· Ph+ ALL
· GIST (adjuvant and
unresectable/metastatic).
Dosing and Administration
Paediatric CML:
340 mg/m²/day, given as a single daily dose or divided into
two doses if total dose ≥340mg. Maximum 600mg/day. Body surface area must be
calculated at each dose review.
Adult dose reduction or titration:
As directed by the haematologist/oncologist based on
toxicity profile and response.
Administration: take with food and a large glass of water.
Swallow whole, or dissolve in water/apple juice for patients who cannot swallow
tablets.
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CAUTION:
DISPENSING
ALERT: Verify the correct strength — 100mg and 400mg are significantly
different doses. Do not substitute one for the other without explicit
prescriber instruction. Confirm dose calculation for paediatric patients at
each dispensing episode. |
Paediatric-Specific
Considerations
• Growth monitoring: long-term imatinib
in children may cause growth retardation. Monitor height and weight at every
clinic visit throughout treatment. Pubertal development should also be assessed
annually.
• Bone health: bone metabolism effects
have been reported in children on long-term imatinib. Monitor for bone pain and
consider DXA if clinically indicated.
• Dissolving tablets: dissolve in water
or apple juice if the child cannot swallow. Stir thoroughly until completely
dissolved and give immediately.
Side Effects
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Frequency |
Side Effects |
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Very Common |
Nausea, vomiting, diarrhoea, oedema
(periorbital puffiness and ankle/lower limb swelling are characteristic),
muscle cramps, bone pain, fatigue, rash |
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Common |
Neutropenia, thrombocytopenia, anaemia,
elevated liver enzymes (ALT/AST), headache, joint pain, fluid retention |
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Serious — Seek Urgent Help |
Severe fluid retention: pleural effusion
(breathlessness, cough), pulmonary oedema, ascites, pericardial effusion —
report sudden weight gain or breathlessness urgently. Hepatotoxicity:
jaundice, dark urine, right upper quadrant pain. Cardiac failure (particularly
in elderly or pre-existing cardiac disease). Stevens-Johnson syndrome (rare). |
Contraindications and Cautions
• Known hypersensitivity to imatinib or
any excipient
• Pregnancy and breastfeeding —
imatinib is teratogenic. Effective contraception is required during treatment and
for 30 days after the last dose.
• Moderate-severe hepatic impairment:
dose reduction to 300mg required; monitor LFTs closely
• Cardiac disease: imatinib is
cardiotoxic — can cause left ventricular dysfunction; baseline cardiac
assessment and regular monitoring in at-risk patients
Key Drug Interactions
• Strong CYP3A4 inhibitors
(ketoconazole, clarithromycin, itraconazole): increase imatinib plasma levels
significantly — monitor for toxicity
• CYP3A4 inducers (rifampicin,
phenytoin, carbamazepine, St. John's Wort): markedly reduce imatinib efficacy —
avoid; consider dose increase if unavoidable
• Warfarin: imatinib inhibits CYP2C9,
increasing warfarin effect. Substitute LMWH for warfarin wherever possible in
patients on imatinib. If warfarin is essential, monitor INR very frequently.
• Simvastatin and other CYP3A4
substrates: imatinib raises their levels — consider statin switch to
pravastatin or rosuvastatin (not CYP3A4-dependent)
• Paracetamol at high doses: increased
hepatotoxicity risk in combination — limit paracetamol dose
Clinical Monitoring Schedule
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PRESCRIBER NOTE FBC: monthly for first 3 months, then every 3
months. LFTs: monthly for the first year, then every 3 months. Renal function:
baseline and periodically. Weight: weekly by patient at home. Molecular
response (BCR-ABL PCR) for CML: every 3 months. Confirm cytogenetic/molecular
diagnosis before dispensing. Avoid warfarin — use LMWH. High-risk oncology
medicine; specialist prescription required. |
Key Dispensing Note
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DISPENSING ALERT: IMANIX 400mg and
IMATIS 400mg contain the same active ingredient at the same strength. Confirm
which product is being dispensed at each episode — do not issue both products
concurrently to the same patient. Verify specialist prescription and
indication documentation before dispensing. |
Frequently Asked Questions
Q: What is Imatis 400mg used for?
It is the standard
adult dose of imatinib, used primarily for chronic myeloid leukaemia (CML), Ph+
ALL, and gastrointestinal stromal tumours (GIST).
Q: What is the difference between Imatis and Imanix?
Both are generic
imatinib 400mg products with the same active ingredient, dose, and indications.
They differ only in brand/manufacturer. Clinically, they are equivalent. Do not
take both at the same time.
Q: What are the most important monitoring tests?
Fluid retention (weekly
weight self-monitoring), liver function (monthly for the first year), and blood
counts are the key ongoing monitoring parameters. Your specialist will arrange
a schedule.