Warnings

Dutasteride

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Apr 29, 2024

Warnings

Dutasteride (Avodart) Risks, Warnings, and Complications

Dutasteride can cause or worsen health problems in some people. Talk to your doctor or pharmacist about other treatment options for an enlarged prostate if you are at an increased risk of complications from this medication. Some of the risks of taking dutasteride include:

MASKING OF PROSTATE CANCER: PSA (prostate-specific antigen) is a substance made by the prostate gland. In men with prostate cancer, PSA concentrations can be high. A blood test to measure PSA is commonly used as a screening tool for prostate cancer.
During clinical trials, dutasteride was found to reduce serum PSA concentrations by approximately 50% after 3-6 months of treatment. Therefore, dutasteride, by causing a decrease in PSA, can potentially mask the presence of prostate cancer.
Your doctor will measure a PSA level 3 months after you start dutasteride treatment to establish a new baseline and repeat the blood test periodically thereafter.
INCREASED RISK OF HIGH-GRADE PROSTATE CANCER: The Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial showed that taking dutasteride leads to an increased incidence of a very serious form of prostate cancer. Another 5 alpha-reductase inhibitor, finasteride, is also associated with an increased risk of developing prostate cancer. There isn’t enough data to say whether dutasteride can increase the risk of breast cancer. Talk to your provider about the risks versus benefits of taking dutasteride.
RISKS DURING PREGNANCY: Animal reproduction studies have shown that dutasteride concentrations producing abnormalities in animals are less than the usual human dose. This medication has been found to prevent the normal development of male offspring external genitalia in rats and rabbits when given at less than the maximum recommended human dose (MRHD) of 0.5 mg daily. At high doses (15 times the MRHD), dutasteride causes prolonged pregnancy, increased placental weights, decreased reproductive organ weights, and delayed puberty in male offspring compared to untreated female rats and rabbits.
Based on these findings, men taking dutasteride for prostate disorders should ensure that their human female partner does not handle dutasteride capsules. If women of childbearing age come in contact with leaking capsules, it can lead to absorption of the medicine through the skin. This can lead to unintended fetal exposure in case the woman is pregnant. In pregnant women, exposure of the unborn baby to dutasteride can put male fetuses at serious risk of birth defects. If a woman comes in contact with leaking dutasteride capsules, the area should be washed immediately with soap and water.
BLOOD DONATION: Dutasteride remains in the blood for a long time. Men on dutasteride therapy should not make blood donations until at least 6 months after the last dose. This is to prevent inadvertent administration of dutasteride to pregnant women through blood transfusions.
EFFECTS ON SEMEN PARAMETERS: Dutasteride treatment can affect semen characteristics and result in a decreased total sperm count, sperm motility, and semen volume. These effects are not reversible for at least 6 months. The clinical significance and expected physiological consequence of these effects on fertility are unknown. Talk to your doctor about these risks if you plan to have children in the future.

Precautions Before Starting Dutasteride (Avodart)

Tell your doctor if you have ever had allergic reactions to dutasteride, any of the active or inactive ingredients in dutasteride (Avodart) capsules, other 5-alpha reductase inhibitors like finasteride (Proscar, Propecia), or any other medications. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, nutritional supplements, and herbal products. This can help avoid possible drug interactions.

Talk to your doctor about drinking grapefruit juice while on dutasteride.

Give your doctor a complete medical history. Dutasteride may not be safe for men with certain health conditions, such as prostate cancer or liver disease.

Precautions During Use of Dutasteride (Avodart)

Keep all your medical and lab appointments during treatment with dutasteride.

Do not donate blood for at least 6 months after your last dose of dutasteride.

Dutasteride is for adult men only. Women, especially pregnant women, should not come in contact with this medicine (it can be absorbed through the skin). If a pregnant woman comes in contact with a leaking dutasteride capsule, wash the contacted area with soap and water immediately.

Tell all your health care providers you are on dutasteride before any surgery, including dental procedures.

Dutasteride (Avodart) Drug Interactions

Certain other drugs can affect how dutasteride works. Possible interactions between dutasteride and other drugs can increase the risk of severe adverse reactions. Some of the medications that can interact with dutasteride include:

Antifungal medications such as ketoconazole (Nizoral)
H2 blockers such as cimetidine (Tagamet)
Certain antibiotics, such as ciprofloxacin (Cipro) and troleandomycin (TAO)
Calcium channel blockers such as diltiazem (Cardizem, Tiazac, Dilacor) and verapamil (Calan, Verelan, Covera, Isoptin)
HIV drugs such as ritonavir (Norvir)

The above list may not describe all the potential interactions of dutasteride. Give your doctor or pharmacist a list of all the medicines you are taking, including prescription drugs, nonprescription drugs, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription and over-the-counter medications.

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