Men Home > Precautions and Warnings With Dutasteride/Tamsulosin

Before using dutasteride/tamsulosin, there are many precautions to be aware of, including warnings relating to who should not use the medication and possible side effects that may occur. For example, this prescription drug may cause sexual side effects and may not be safe for people who have a history of low blood pressure.

What Should I Tell My Healthcare Provider Before Taking Dutasteride/Tamsulosin?

You should talk with your healthcare provider prior to taking dutasteride/tamsulosin (Jalyn™) if you have:
Also, let your healthcare provider know if you are:
  • Pregnant or thinking of becoming pregnant
  • Breastfeeding.
Make sure to tell your healthcare provider about any other medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.

Specific Dutasteride/Tamsulosin Precautions and Warnings

Some warnings and precautions to be aware of prior to taking this drug include the following:
  • Before you start treatment with dutasteride/tamsulosin, and while you are taking it, your healthcare provider may check to make sure your enlarged prostate symptoms are not caused by another condition, such as prostate cancer or bladder problems.
  • Sometimes, a blood test called a prostate-specific antigen (PSA) test is used to check for prostate cancer (see Prostate Cancer Screening). Dutasteride/tamsulosin can lower your PSA levels in the blood. Your healthcare provider will adjust your PSA test result if you are taking dutasteride/tamsulosin, or he or she may use a slightly different test called the percent-free PSA. Any increase in PSA while taking this medication (even if still within the normal range) should be further evaluated, as this may be a possible sign of prostate cancer.


  • Studies have shown that dutasteride may increase the risk of a serious type of prostate cancer. You should discuss this risk with your healthcare provider, especially if you have a family history of prostate cancer. Interestingly, dutasteride appears to decrease the risk of less serious prostate cancers. 


  • You should not donate blood while taking dutasteride/tamsulosin or for at least six months after you stop taking this medicine. The reason for this is to prevent pregnant women from being exposed to dutasteride/tamsulosin through donated blood.
  • If you have liver problems, including liver failure or cirrhosis, you should talk with your healthcare provider before taking dutasteride/tamsulosin. The liver helps remove dutasteride/tamsulosin from the body, so the medication could accumulate in people who have liver problems.
  • Men with severely decreased urine flow, or men who can only empty very little of their bladder at a time, should be closely monitored by their healthcare providers. Dutasteride/tamsulosin may not be the best option for these men.
  • Dutasteride/tamsulosin can cause a sudden decrease in blood pressure (hypotension), especially when sitting or standing up. This may lead to fainting, dizziness, or feeling lightheaded. This side effect is more common when dutasteride/tamsulosin is first started.

If you experience any of these symptoms, make sure to avoid situations that might be dangerous, such as driving or operating heavy machinery. It may also be a good idea to sit or stand up slowly. Make sure to tell your healthcare provider if you have any of these symptoms.

  • Very rarely, dutasteride/tamsulosin can cause a condition called priapism, a painful erection of the penis that does not go away. If you experience an erection for longer than four hours while taking dutasteride/tamsulosin, seek immediate medical attention. Although it may seem embarrassing, if not treated immediately, priapism may lead to permanent damage to the penis and impotency.
  • Dutasteride/tamsulosin can cause a condition called intraoperative floppy iris syndrome, a problem with the eyes that can occur during cataract surgery. This problem can occur if you currently take dutasteride/tamsulosin or if you have taken it in the past. Before having eye surgery, make sure to tell your healthcare provider if you are or have ever been on dutasteride/tamsulosin.
  • Although it is very rare, people who have a sulfa allergy might also be allergic to dutasteride/tamsulosin. If you have a sulfa allergy that has caused severe or life-threatening reactions in the past, talk with your healthcare provider before taking dutasteride/tamsulosin.
  • Dutasteride/tamsulosin can interact with a number of different medications (see Drug Interactions With Dutasteride/Tamsulosin).
  • Dutasteride/tamsulosin can cause sexual side effects, including a decreased libido (sex drive), erectile dysfunction (ED or impotence), and a decreased ejaculate amount. Men taking dutasteride/tamsulosin may also have reduced sperm counts during treatment and for at least 24 weeks after stopping this medication. It is currently unknown if this reduced sperm count affects fertility (see Jalyn Sexual Side Effects).
  • Dutasteride/tamsulosin is considered a pregnancy Category X medication. This means that it is very dangerous for use during pregnancy. Women who are pregnant or who may become pregnant should not take dutasteride/tamsulosin or even touch one of the capsules (see Jalyn and Pregnancy).
  • It is unknown if dutasteride/tamsulosin passes through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, discuss this with your healthcare provider prior to taking the drug (see Jalyn and Breastfeeding). It's important to remember that this medication is not approved for use in women.
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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