Cyclophosphamide: Uses, Dosage, and Side Effects

What Is Cyclophosphamide?

Cyclophosphamide is an alkylating agent that is used in chemotherapy. It helps fight many kinds of cancer, like leukemia, breast cancer, ovarian cancer, and lymphoma. It is also used to help people with very serious autoimmune diseases by calming down the immune system.

Is Cyclophosphamide FDA-Approved?

It was approved by the FDA (Food and Drug Administration) in the year 1959.

How Cyclophosphamide Works?

Cyclophosphamide works by damaging the DNA and RNA inside cancer cells. DNA carries instructions, and RNA helps turn those instructions into proteins. When these are damaged, the cancer cells cannot grow or divide anymore, so they die.

Let’s see how it works step by step:

• Activation: When Cyclophosphamide is given (by mouth or into a vein), it goes to the liver. In the liver, special helper enzymes called cytochrome P450 (CYP450) change it into its active form. The main active form is called phosphoramide mustard, which fights cancer cells. Another substance, acrolein, is also produced. Acrolein does not help treat cancer and can hurt the bladder.

• Damage to the DNA: The toxic forms of Cyclophosphamide stick to the DNA and make links inside it and between DNA strands. These cross-links damage the DNA, so the cell cannot work properly anymore.

• Cell Death: The DNA links stop the DNA from opening and separating, which the cell needs to divide. Because of this, the cell cannot grow or make new cells. Then the cell undergoes a programmed form of cell death called apoptosis. This happens to cancer cells and also to some immune cells.

What Is Cyclophosphamide Used For?

• Breast cancer.

• Ovarian cancer.

• Lung cancer.

• Leukemia.

• Lymphomas (including Hodgkin’s and Non-Hodgkin’s lymphoma and mycosis fungoides).

• Multiple myeloma (cancer of the bone marrow).

• Neuroblastoma (cancer of nerve cells).

• Retinoblastoma (cancer of the eye).

• Brain tumors.

It is also used to treat autoimmune diseases like:

• Severe lupus.

• Vasculitis.

• Rheumatoid arthritis.

• Nephrotic syndrome (a kidney disease).

Sometimes, Cyclophosphamide is used to prepare the body before stem cell treatment.

What Is the Dosage and Administration of Cyclophosphamide?

The amount of Cyclophosphamide varies from person to person. Doctors decide the dose. Always follow the doctor’s instructions and never change the dose by yourself. The information below shows the usual (average) doses.

For treating cancer:

• Adults: The dose is based on body weight. Usually, it is 1 to 5 milligrams (mg) for each kilogram (kg) of body weight per day.

• Children: The dose is also based on body weight. Usually, it is 1 to 5 mg/kg body weight per day.

Cyclophosphamide can be taken as a tablet by mouth. The tablet should be swallowed whole and not crushed or chewed. Take it at the same time every day, usually in the morning, so the kidneys can clear it better. Do not touch broken or leaking tablets with your bare hands.

Use rubber or latex gloves to pick them up. Wash your hands right away if the medicine comes into contact with your skin. It can also be given into a vein (intravenous) in a hospital. When given this way, it is slowly injected or given as a drip by healthcare workers.

What Are the Side Effects of Cyclophosphamide?

Cyclophosphamide can cause some side effects. These can be mild or serious. Below are some common side effects:

Common Side Effects:

• Hair loss.

• Nausea.

• Vomiting.

• Infertility.

• Irregular periods.

• Skin color changes and nail changes

• Loss of appetite.

• Mouth sores.

• Weakness.

• Fatigue.

• Frequent urination.

Risks: These side effects are serious. If any of these occur, contact a doctor immediately.

• Severe bone marrow suppression.

• Infections.

• Bladder issues, like blood in the urine.

• Heart problems, such as chest pain, an irregular heartbeat, shortness of breath, or swelling in the feet.

• Kidney problems, such as lower back or side pain.

• Lung problems, like pulmonary fibrosis (scarring in the lungs that makes breathing hard).

• Liver damage, including liver injury from toxins or blocked blood vessels in the liver.

• Problems having children later (infertility).

• Unusual bleeding or bruising.

• Trouble breathing.

• Hemorrhagic cystitis, where the bladder lining becomes sore and bleeds.

• Nosebleeds.

• Black, tar-like stools.

• Severe stomach pain.

• Worsening cough.

• Yellowing of the skin or eyes (jaundice).

• Severe nausea and vomiting.

• Using Cyclophosphamide for a long time may increase the risk of getting another cancer later, such as leukemia or bladder cancer.

What Precautions Should Be Taken While Taking Cyclophosphamide?

Some important safety steps should be followed while taking Cyclophosphamide:

• Drink lots of fluids. This helps protect the bladder. Try drinking 0.5 to 0.7 gallons of water each day and peeing often to help reduce bladder irritation.

• Do not use during pregnancy. This medicine can harm the baby and may cause birth defects or miscarriage.

• Use birth control. Women should use contraception for at least 1 year, and men for 6 months, after treatment to prevent birth defects.

• Do not breastfeed during treatment and for 1 week after treatment ends.

• Prevent infections. Wash your hands often and avoid people who are sick.

• Be careful to avoid bleeding. Use a soft toothbrush and an electric shaver to prevent cuts.

• Avoid vaccinations. This medicine lowers immunity, so vaccines should only be taken if the doctor allows them.

What Are the Interactions of Cyclophosphamide?

Cyclophosphamide interacts significantly with drugs that affect the liver enzyme CYP450.

Medicines that can interact:

• Liver Enzyme Modulators: Some medicines affect liver helpers called CYP450 enzymes. These include Phenobarbital, Dexamethasone, and Phenytoin. They can make Cyclophosphamide break down faster and may lower white blood cells.

• Allopurinol: Using this with Cyclophosphamide can increase bone marrow damage.

• Antifungals: Drugs like fluconazole can increase Cyclophosphamide’s effects and raise the risk of side effects.

• Succinylcholine: Using this together can cause muscles to stay relaxed for too long.

• Thiazide Diuretics: These can increase the toxic effects of Cyclophosphamide.

• Tamoxifen: Using both can raise the risk of blood clots.

• Metronidazole: This medicine can increase Cyclophosphamide toxicity.

• Vaccines: Live vaccines should be avoided because this medicine weakens the immune system.

• Food and Drink Interactions: Avoid alcohol and grapefruit, as they can worsen side effects.

Who Should Not Take Cyclophosphamide?

Cyclophosphamide should not be used in these people:

• People who are allergic to Cyclophosphamide.

• People with very low blood counts, such as low white blood cell or platelet counts (severe bone marrow suppression).

• People with blocked urine flow, because this medicine can damage the bladder.

• Pregnant women and breastfeeding mothers should not because this medicine can harm the baby and pass into breast milk.

• People with active infections, such as chickenpox or shingles.

• People with kidney or liver problems, because the drug can build up in the body and cause toxicity.

• People with heart disease, because Cyclophosphamide can increase the risk of heart problems.

• People who have had radiation therapy or chemotherapy before, as this medicine can cause stronger side effects.

• People with adrenal insufficiency, because the medicine may not be safe for them.

Conclusion

Cyclophosphamide is a strong medicine used to treat cancer and some autoimmune diseases. It works by damaging the DNA of cancer cells, which stops them from growing, and by calming down the immune system. This medicine can cause side effects that may be mild or serious. Drinking plenty of water is very important while taking this medicine to protect the bladder. It is also important to tell the doctor about any health problems or medicines you are already taking, because Cyclophosphamide can interact with them and cause problems. If you are taking this medicine and want to know more, you can talk to a cancer specialist for more help and information.

Key Takeaways

• Cyclophosphamide is a chemotherapy medicine. It helps treat many types of cancer by targeting and damaging the DNA in cancer cells. It also helps people with autoimmune diseases by calming the immune system.

• Cyclophosphamide treatment usually lasts about 3 to 6 months to help the body get better. It is often given in cycles every 2 to 4 weeks. In very serious cases, treatment can last up to 6 months or even 1 year.