FDA approved indications:

• Adjuvant treatment for node-positive breast cancer [1]
• Treatment of metastatic breast cancer after failure of combination chemotherapy that included an anthracycline [2]
• Treatment of metastatic breast cancer that relapsed within six months of adjuvant chemotherapy that included an anthracycline [3][4]
• Treatment of AIDS-related Kaposi sarcoma (second line)[5]
• Treatment of non-small cell lung cancer in combination therapy with cisplatin in patients who are not candidates for surgery and/or radiation therapy[6]
• Treatment of ovarian cancer in combination with cisplatin[7][8]
• Subsequent therapy for the treatment of advanced ovarian cancer in combination with cisplatin[9][10]

Non-FDA approved indications:

• Treatment of metastatic or advanced bladder cancer in combination therapy with gemcitabine[11][12]
• Treatment of advanced cervical cancer in combination with topotecan, bevacizumab, and/or cisplatin[13][14][15]
• Preoperative management of esophageal and gastric cancers in combination with carboplatin and radiation therapy[16]
• Treatment of advanced head and neck cancer in combination with cisplatin[17]
• Neoadjuvant treatment in penile cancer with bulky regional lymph node metastases[18]
• Treating relapsed or refractory small-cell lung cancer[19][20]
• Treatment of advanced or unresectable angiosarcoma [21][22]
• Treatment of relapsed or refractory testicular germ cell tumors in combination with gemcitabine and oxaliplatin or ifosfamide and cisplatin[23][24][25]
• Treatment of advanced thymoma/thymic carcinoma in combination with carboplatin[26]
• Treatment of unknown primary adenocarcinoma in combination with carboplatin and/or etoposide [27][28]
• Treatment of endometrial carcinoma[29]
• Treatment of metastatic or unresectable esophageal cancer[30]
• Treatment of metastatic or unresectable gastric cancer[31]
• Treatment of melanoma[32]
• Treatment of anaplastic thyroid cancer[33]

Paclitaxel is an antimicrotubule agent. It promotes the assembly of microtubules by enhancing the action of tubulin dimers and stabilizing current microtubules while inhibiting their disassembly. Due to the stability of the microtubules, the late G2 phase stops, and cell replication becomes inhibited. Paclitaxel may also distort mitotic spindles causing the chromosomes to break.[34]

Paclitaxel is available as an IV formula infused over 3 to 24 hours, depending on the indication or protocol. Certain off-label protocols use a 1-hour infusion, as well as off-label intraperitoneal use. Paclitaxel infusion should be through a 0.22-micron in-line filter and polyethylene-lined administration set (non-PVC).[35] If the drug is part of a combination chemotherapy regimen, the order may vary by regimen, and it is important to refer to a protocol for the recommended sequence. Patients may also be premedicated with dexamethasone, diphenhydramine, cimetidine, or ranitidine before the infusion.[36][37][38] Because paclitaxel is such a potent irritant, care to avoid extravasation must be taken. Caution with needle and catheter position is essential during the administration of the medication.  

Paclitaxel has a black box warning for hypersensitivity reactions and bone marrow suppression. Patients should be premedicated with corticosteroids, diphenhydramine, and H2 antagonists prior to infusion to avoid anaphylaxis and severe hypersensitivity reactions. The recommendation is for dexamethasone at 20 mg IV or orally (10 mg if the patient has advanced HIV) at 12 and 6 hours before the paclitaxel dose. Diphenhydramine should be administered 30 to 60 minutes before the dose at 50 mg IV. Cimetidine 300 mg, famotidine 20 mg, or ranitidine 50 mg would all be appropriate choices to be administered IV at 30 to 60 minutes before the dose. Severe hypersensitivity reactions would include dyspnea requiring bronchodilators, hypotension requiring treatment, angioedema, and/or generalized urticaria. In cases of serious hypersensitivity reaction, stop the infusion and discontinue paclitaxel. Minor hypersensitivity reactions do not require treatment to be interrupted or discontinued. Minor hypersensitivity reactions would include flushing, dyspnea, hypotension, skin reactions, or tachycardia.[39][40]

The most prevalent side effects of paclitaxel are alopecia, nausea and vomiting, mucositis, neutropenia, leukopenia, anemia, hypersensitivity reactions, arthralgia, myalgia, and weakness. Peripheral neuropathy is another common side effect, and patients with preexisting neuropathies may have an increased risk. The dose should be reduced by 20% for patients who develop severe neuropathy.[41]

Other less common side effects include flushing, edema, hypotension, skin rash, stomatitis, thrombocytopenia, hemorrhage, increased serum alkaline phosphatase and AST, local injection site reaction, increased serum creatinine, along with many more. Injection site reactions generally are mild (erythema, tenderness, skin discoloration, or swelling) and tend to occur more often with an extended infusion duration, like 24 hours, for example. It is worth noting that delays of injection site reactions can extend from 7 to 10 days. Patients may also experience infusion-related hypotension, bradycardia, and/or hypertension. Due to that concern, the recommendation is that the patient's vital signs undergo frequent monitoring, especially during the first hour of infusion.[42] 

Due to the black box warning for hypersensitivity reactions and bone marrow suppression, paclitaxel should not be given to patients who have had a severe hypersensitivity reaction with paclitaxel, patients with solid tumors who have a baseline neutrophil count of fewer than 1500 cells/mm^3, or patients with AIDS-related Kaposi sarcoma if the baseline neutrophil count is less than 1000 cells/mm^3. Bone marrow suppression is dose-dependent and is a dose-limiting toxicity. If it occurs, future doses should be reduced by 20% for severe neutropenia and consider supportive therapy (growth factor treatment).[43]