sunitinib malate

Action

Inhibits multiple receptor tyrosine kinases, some of which are implicated in tumor growth, pathologic angio-genesis, and metastatic cancer progression

Availability

Capsules: 12.5 mg, 25 mg, 50 mg

Indications and dosages

➣ GI stromal tumor after disease progression with or intolerance to imatinib mesylate; advanced renal cell carcinoma

Adults: 50 mg P.O. daily on cycle of 4 weeks on and 2 weeks off treatment; may increase or decrease dosage in 12.5-mg increments based on safety and tolerance

Dosage adjustment

• Concurrent use of strong CYP3A4 inducers or inhibitors

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:

• left ventricular dysfunction, hypertension, history of prolonged QT interval, concurrent use of antiarrhythmics, patients with relevant preexisting cardiac disease, bradycardia, or electrolyte disturbances

• patients who have experienced cardiac events within previous 12 months

• hepatotoxicity

• concurrent use of strong CYP3A4 inhibitors

• pregnant or breastfeeding patients

• children (safety and efficacy not established).

Administration

See Monitor liver function tests before start of treatment.

• Administer with or without food.

• Interrupt therapy or reduce dosage, as prescribed, in patients who lack clinical evidence of heart failure but have ejection fractions (EFs) below 50% and above 20% below baseline.

Adverse reactions

CNS: headache, asthenia

CV: hypertension, left ventricular dysfunction

EENT: epistaxis, oral pain

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, mucositis, stomatitis, anorexia

Hematologic: bleeding, anemia, thrombocytopenia, neutropenia, lymphopenia, hemorrhage

Hepatic: hepatotoxicity

Metabolic: acquired hypothyroidism, adrenal toxicity

Musculoskeletal: arthralgia, back pain, limb pain, myalgia

Respiratory: dyspnea, cough, pulmonary embolism

Skin: skin abnormalities, skin discoloration, rash, palmar-plantar erythrodysesthesia, alopecia, hair color changes

Other: altered taste, fatigue, fever

Interactions

Drug-drug. Atazanavir, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole: increased sunitinib blood level

Carbamazepine, dexamethasone, phenobarbital, phenytoin, rifabutin, rifampin, rifapentin: decreased sunitinib blood level

Drug-diagnostic tests. Amylase, creatinine, lipase, uric acid: increased

Liver function tests: abnormal

Serum phosphorus, potassium, sodium: decreased

Drug-food. Grapefruit juice, pomegranate: increased sunitinib blood level

Drug-herbs. Alpha-lipoic acid: decreased chemotherapeutic efficacy

American elder, bishop's weed, cat's claw, devil's claw, eucalyptus, feverfew, Siberian ginseng, valerian: increased sunitinib blood level

St. John's wort: unpredictable decrease in sunitinib blood level

Patient monitoring

• Obtain CBC with platelet count and blood chemistries (including phosphate) at start of each treatment cycle and frequently thereafter.

• Know that physician may order baseline and periodic evaluation of left ventricular EF in patients who experienced cardiac events within 12 months before starting drug. Watch closely for signs and symptoms of left ventricular dysfunction (especially heart failure).

• Be aware that physician may order baseline EF testing for patients without cardiac risk factors.

• Monitor for hypertension; administer standard antihypertensive therapy as ordered and needed.

• Monitor for adrenal insufficiency if patient experiences stress (as from surgery, trauma, or severe infection).

See Monitor liver function tests during each cycle of treatment and as clinically indicated. Interrupt therapy for Grade 3 or 4 drug-related hepatic adverse events; discontinue drug if no resolution. Don't restart drug if severe changes in liver function tests subsequently occur or if patient has other signs and symptoms of liver failure.

Patient teaching

• Instruct patient to take drug with or without food.

See Urge patient to immediately report sudden signs and symptoms of liver problems (such as yellowing of skin or eyes, unusual tiredness, loss of appetite), chest pain, swelling, or difficulty breathing.

• Tell patient drug may cause skin changes (drying, cracking, or rashes on hands or feet) and hair color changes.

• Advise patient to consult prescriber before taking other drugs, including over-the-counter drugs and herbs.

• Caution patient not to take St. John's wort during therapy.

• Advise female with childbearing potential to avoid pregnancy and breastfeeding during therapy.

•As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.

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