Paclitaxel and docetaxel

Paclitaxel and docetaxel

Antineoplastic drugs are used to treat metastatic ovarian andbreast cancer after chemotherapy has failed. They include:

·                 paclitaxel

·                 docetaxel.

Pharmacokinetics

After I.V. administration, paclitaxel is highly bound to plasma pro-teins. Docetaxel is administered I.V. with a rapid onset of action.

Metabolism and excretion

Paclitaxel is metabolized primarily in the liver with a small amount excreted unchanged in urine. Docetaxel is excreted pri-marily in stool.

Pharmacodynamics

Paclitaxel and docetaxel exert their chemotherapeutic effect by disrupting the microtubule network essential for mitosis and oth-er vital cellular functions.

Pharmacotherapeutics

Paclitaxel is used when first-line or subsequent chemotherapy has failed in treating metastatic ovarian cancer as well as metastatic breast cancer.

Head, neck, and below

The taxanes may also be used for treating head and neck cancer, prostate cancer, and non–small-cell lung cancer. (See Culturalconsiderations with docetaxel use.)

Drug interactions

Taxanes may interact with other drugs.

·                 Concomitant use of paclitaxel and cisplatin may cause additive myelosuppressive effects.

·                 Cyclosporine, ketoconazole, erythromycin, and troleandomycin may modify the metabolism of docetaxel.

·                 Phenytoin may decrease paclitaxel serum level, leading to a loss of efficacy.

·                 Quinupristin/dalfopristin may increase paclitaxel serum levels, increasing the risk of toxicity. (See Adverse reactions to paclitax-el and docetaxel.)