Paclitaxel is an anti-cancer drug which can be used to combat many different forms of cancer. It is sometimes marketed under the name Taxol. This medication functions by preventing cancer cells from dividing and separating into two new cells, ultimately blocking the growth of the cancer.
The compound was initially isolated from the Pacific yew tree in 1971, although it was not officially approved for medical use until 1993. It is now regarded as an essential medicine by the World Health Organization on account of its efficacy and low wholesale cost. While it was initially extracted from the Pacific yew, it is now almost always exclusively manufactured via cell culture.
Since 2001 Paclitaxel has been approved for the treatment of solid tumor diseases such as ovarian, breast, lung, melanoma, prostate and esophageal cancers. It can also be effective in the treatment of Kaposi's sarcoma, a cancer associated with HIV and AIDS.
Paclitaxel has other medicinal properties also. It can be prescribed as an antiproliferative agent to help prevent recurrent narrowing of peripheral and coronary stents (restenosis). When locally administered to the artery wall, Paclitaxel limits the growth of scar tissue (neointima) within the stents. Some drug manufacturers now market Paclitaxel-coated stents on this basis.
Like many medicines, Paclitaxel can cause unwanted side effects in addition to its desired effects. Some of the most commonly reported side effects by patients undergoing treatment with this medicine include the following:
As the patient continues to undergo chemotherapy with Paclitaxel as prescribed by a qualified physician, most (if not all) of the previously mentioned side effects should begin to lessen. If symptoms appear to get worse over time or persist for a prolonged period, the patient should inform their doctor as soon as possible. In some instances, a doctor or pharmacist might be able to recommend over the counter remedies or other prescription drugs to alleviate side effects which cause mild discomfort.
Most patients generally only experience mild side effects while undergoing treatment with Paclitaxel â€“ if they observe any at all. Most healthcare professionals agree that the benefits of treating serious cancers with Paclitaxel outweigh the risks of experiencing temporary side effects.
Other side effects experienced rarely, albeit often enough to warrant mentioning, include the following:
The following side effects have been reported extremely rarely, and their level of incidence is unknown:
Because Paclitaxel can potentially affect the psychology of the patient, caution should be taken after it has been administered to those with a history of mental health conditions (such as depression, bipolar disorder or schizophrenia).
Paclitaxel can also affect the co-ordination of the patient. It is therefore advisable for the patient to refrain for driving or operating heavy machinery until it has been observed that they do not pose a risk to themselves or other road users.
Not all side effects may have been listed or reported. Patients who think they may have experienced an unreported side effect should inform their doctor and report their findings to the FDA.
As with all drugs, it is important for Paclitaxel to be administered only as prescribed by a qualified physician with an expertise in chemotherapy. This means that patients should not receive more of the medicine than advised, either in terms of dose size or frequency. In addition to this, the patient should no longer receive further treatment with this medication if the prescribing doctor advises so.
All patients undergoing treatment with Paclitaxel should be premedicated beforehand to prevent extreme hypersensitivity reactions from occurring.
Typical adult dosage for ovarian cancer:
Previously untreated patients with ovarian cancer should receive 175mg/m2 of Paclitaxel, intravenously, over a three-hour period, administered every three weeks. This should be followed by a course of another chemotherapy drug called Cisplatin. Alternatively, the patient may receive 135mg/m2 of Paclitaxel, intravenously, over a 24-hour period, every three weeks. This again should be followed by treatment with Cisplatin.
Typical adult dosage for breast cancer:
Paclitaxel is suitable for the treatment of breast cancer in patients when initial chemotherapy for metastatic disease has failed, or relapse within six months of chemotherapy with an adjuvant has occurred. In this instance, the patient should receive 175mg/m2 of Paclitaxel, intravenously, over a three-hour period, every three weeks.
Typical adult dosage for non-small cell lung cancer:
Patients with this condition should receive 135mg/m2 of Paclitaxel over a 24-hour period, followed by therapy with Cisplatin, every three weeks. Paclitaxel is suitable for patients with non-small cell lung cancer who are not suitable for radiation therapy and/or curative surgery.
Typical adult dosage for Kaposi's sarcoma:
Patients with this AIDS-related illness should receive 135mg/m2 of Paclitaxel, intravenously, over a three-hour period, every three weeks. Alternatively, the patient may receive 100mg/m2 of Paclitaxel, intravenously, over a three-hour period, every two weeks.
Patients in the advanced stages of HIV should have their dose of dexamethasone reduced prior to commencing chemotherapy with Paclitaxel. Treatment should only be initiated in such patients if their neutrophil count is 1000 cells per mm3 or greater. Patients who experience extreme neutropenia should have subsequent courses of Paclitaxel reduced by 20 per cent.
While the manufacturers of Paclitaxel provide general dose instructions, it must be reiterated that these are merely guidelines which can be altered at the discretion of the prescribing doctor. Diagnostic tests and factors discussed between patient and doctor will play a role in determining the optimum dosage, along with the age, height, weight, and condition of the patient.
In the event of missing a dose, the patient should reschedule the missed dose for as soon as possible, before continuing with the dosage schedule as standard. Patients who miss a dose should not receive a double dose, and this could potentially cause hypersensitive reactions or an overdose.
Patients who experience signs of an overdose while undergoing treatment with this or any other medicine may require urgent medical attention. If this is the case, the patient or their caregiver should alert a healthcare professional within the administering clinic, contact the local poison control center on 1800-222-1222 or call emergency services on 911 immediately.
All drugs can potentially interact with other chemicals or drugs within the human body. These interactions can potentially cause one or more of the medicines involved to stop functioning in the way they normally would, becoming ineffective at treating the condition they were prescribed to combat. In other cases, interactions can cause potentially dangerous or even fatal side effects to occur. Because of these risks, it is vital for the patient to keep a fully detailed list of all medicines they are currently undergoing treatment with. This includes vitamins, herbal supplements, over the counter remedies and complimentary medicines.
The following is a list of medications known to interact negatively with Paclitaxel. Patients who are currently taking any of these medicines should inform their doctor or healthcare provider prior to beginning chemotherapy with Paclitaxel:
Paclitaxel should not be administered unless under the supervision of an experienced physician who is familiar in the use of chemotherapeutic medication. Additionally, it should only be administered in a clinic or healthcare facility that is appropriately equipped to deal with any complications which may arise as a result of Paclitaxel use (such as hypersensitivity reactions or overdose).
Approximately 2-4 per cent of patients who undergo treatment with Paclitaxel encounter severe hypersensitivity reactions. The most common reactions are hypotension and dyspnea, both of which generally require clinical treatment.
Patients with solid tumors and baseline neutrophil counts of 1500 or less are not suitable for treatment with Paclitaxel.
All patients should be pre-treated with a course or diphenhydramine, corticosteroids and H2 agonists before undergoing a course of chemotherapy. This is to prevent discomfort cause by hypersensitive reactions. Patients with severe hypersensitive reactions must not be re-challenged with Paclitaxel â€“ the prescribing doctor should be able to devise an alternative course of treatment.
The safety and efficacy of Paclitaxel has not been established in patients below the age of 18. While this medication can be used in younger patients, it is generally prescribed at the discretion of the prescribing doctor. Patients under the age of 18 may require parental consent before undergoing treatment with Paclitaxel.
Paclitaxel can cause blood cell counts to become much lower than normal. Blood cells are required to help the blood to clot, and to fight infection. As a result, patients undergoing treatment with Paclitaxel may notice that they are more susceptible to infections or bleeding. In the event of any unusual bruising, bleeding or signs of severe infection (such as chills, body aches and fevers) the patient should contact their doctor as soon as possible.
Patients who are allergic to polyoyethylated castor oil are not suitable for treatment with Paclitaxel or any other medication containing this ingredient. Other cancer medications which contain this substance include Teniposide and Cyclosporine.
To ensure that treatment with Paclitaxel is safe, patients are advised to inform their doctor if they have any of the following conditions:
Paclitaxel is not suitable for pregnant women, as it can potentially cause serious harm to an unborn fetus. Women who are undergoing treatment with Paclitaxel are therefore advised to use an effective form of birth control, and to inform their doctor if they accidentally fall pregnant during the course of chemotherapy.
It is unknown whether Paclitaxel is excreted into breastmilk, or whether it could harm a nursing baby. Official FDA advice suggests that women should refrain from breastfeeding while they are using this medication.
Paclitaxel should be stored and administered in a clinical environment. The patient's healthcare provider is responsible for ensuring that it is stored in accordance with FDA guidelines and administered via an inline filter featuring a micro-porous membrane less than 0.22 micron.
Paclitaxel is a greatly beneficial drug; however, it can potentially pose a risk to patients who do not communicate fully with their doctors and healthcare providers. As a treatment designed to prevent cancerous cells from multiplying, it is effective in combatting lung, breast, ovarian and esophegeal cancers among others. However, it can also cause feelings of dizziness, drowsiness, shortness of breath and other side effects which can potentially affect the day-to-day functioning of the patient.
When administered correctly, Paclitaxel can help patients overcome even the most aggressive tumors, providing them with a much greater quality of life. To achieve this, patient and doctor must work together in order to ensure the treatment is safe, effective and does not interact with any other medicines the patient may be taking.