How and when to take Flomax (tamsulosin) for kidney stones

Medically reviewed by Dr. Mavra Farrukh

Key Takeaways

  • Flomax (tamsulosin) is commonly used off-label to aid in the passage of kidney stones, particularly those larger than 5mm, by relaxing muscles and widening the ureter.
  • Understanding kidney stone risk factors, including gender, family history, and previous incidents, can help prevent it.
  • Seek medical attention for symptoms like severe pain, blood in urine, or difficulty urinating, ensuring timely diagnosis and treatment of kidney stones.


Worried about kidney stones and their scary treatment options? Treatment options vary in different people depending upon the size and shape of their kidney stones. It can either pass naturally or need surgical intervention via medical expulsive therapy (MET) which employs medications to help pass the kidney stones out of the body. Flomax (tamsulosin) is a medication frequently utilized off-label for this purpose. In this blog, we will explore the role of Flomax in managing kidney stones, exploring its mechanisms, potential benefits, and more.

How does Flomax work?

Flomax operates within the alpha-1 blocker class of medications, a group commonly employed in the treatment of an enlarged prostate, medically termed benign prostatic hyperplasia (BPH). Notable examples within this class include Rapaflo (silodosin) and Uroxatral (alfuzosin).

The primary function of alpha-1 blockers is to induce relaxation in the prostate muscles, easing the process of urination. In kidney stones, these medications are crucial in widening the ureter, the tube connecting the kidney to the bladder. By doing so, they provide greater space for the passage of larger stones.

Research indicates that alpha-1 blockers, such as Flomax, may exhibit optimal efficacy for kidney stones exceeding 5 mm in size. A randomized controlled trial demonstrated a quicker passage of kidney stones and reduced reliance on pain medication with Flomax compared to a placebo (a pill devoid of active medication).

Suffering from a kidney stone? Get a prescription for Flomax with Your Doctors Online.

When to take Flomax?

For optimal effectiveness, taking tamsulosin (Flomax) in the morning, following breakfast, or the initial meal or snack of the day is recommended. This strategic timing is based on the observation that the highest concentrations of the medication are reached in the body approximately 6 hours post-administration. By following this schedule, individuals can derive maximum benefit during daytime hours when the urge to urinate is typically more pronounced.

Is Flomax an effective treatment for kidney stones? 

While Flomax is primarily prescribed to address benign prostatic hyperplasia (BPH), healthcare providers may prescribe its off-label use for individuals dealing with kidney stones. The prescription details, including dosage and duration, will be tailored based on the stone’s severity and the individual’s response to the medication.

Role of Flomax in kidney stone treatment

Recent data underscores Flomax’s efficacy in enhancing the passage of kidney stones, particularly those smaller than 5mm. Through its muscle-relaxant properties on the ureter, Flomax facilitates smoother stone movement, reducing the time required to transit through the urinary tract.

Considerations for usage

It is essential to recognize that Flomax may not be universally suitable for all individuals with kidney stones. Healthcare providers will assess individual circumstances to determine the appropriateness of Flomax as a treatment option.

Effectiveness and outcomes

Studies indicate that Flomax can contribute to an improved stone passage rate, potentially minimizing the necessity for invasive interventions like surgery or lithotripsy. Nevertheless, responses to Flomax vary among individuals, and it does not guarantee the successful passage of all kidney stones. Notably, Flomax has effectively reduced the duration of stone passage, offering relief from associated pain and discomfort.

Suffering from a kidney stone? Get a prescription for Flomax with Your Doctors Online.

How long to take it for?

Flomax provides rapid action relief, significantly reducing the time required to pass stones through the urinary tract within 48 hours of initiating the medication. However, for certain individuals, symptom improvement may take 2-4 weeks.

What If you forget to take it?

In the event of a missed dose of tamsulosin, if remembered on the same day, take the missed dose as soon as recollected. If the omission is realized the following day, skip the missed dose and resume with the next scheduled dose. Avoid doubling up on doses to compensate for a missed one.

Alternatives medications

In patients who are unable to take Flomax or it doesn’t work that effectively, the doctors may recommend some alternatives belonging to the class of alpha-blockers, including:

  • Silodosin
  • Alfuzosin
  • Non-branded tamsulosin

Pain management with kidney stones  

Utilizing over-the-counter pain relievers such as ibuprofen (Advil, Motrin), acetaminophen (Tylenol), or naproxen (Aleve) can assist in managing discomfort during the passage of kidney stones. Additionally, your doctor might prescribe an alpha blocker to relax the muscles in your ureter, facilitating a quicker and less painful passage of the stones.

Who is most at risk of kidney stones?

Certain demographic and lifestyle factors increase the likelihood of developing kidney stones. Understanding these risk factors is essential for proactive management and prevention. Key considerations include:

  • Gender Disparity: Men are more predisposed to the development of kidney stones compared to women.
  • Family History: Individuals with a family history of kidney stones face an elevated risk of experiencing them.
  • Previous Incidents: Those who have previously had kidney stones are more susceptible to recurring episodes.
  • Hydration Levels: Inadequate fluid intake increases the risk of kidney stone formation.
  • Obesity: Increased weight is also associated with the chances of having kidney stones.

Being aware of these risk factors empowers individuals to adopt preventive measures and consult healthcare professionals for personalized guidance.

How quickly does Flomax work for kidney stones?

The average time for the flomax to dissolve in the bloodstream and start working is under 48 hours, within which it starts decreasing the time of passing stones out of the body. However, the duration can vary in individuals and may take 2-4 weeks to show improvement. 

Suffering from a kidney stone? Get a prescription for Flomax with Your Doctors Online.

When should I see a doctor?

The presence of a kidney stone may not be apparent until it initiates its journey through the urinary tract. At this stage, individuals may encounter the following symptoms:

  • Pain during urination
  • Urine with a reddish, pinkish, or brown hue indicates blood in the urine
  • Foul-smelling or cloudy urine
  • Waves of varying-intensity pain
  • Pain localized in the back and/or side(s)
  • Nausea and vomiting
  • Fever often accompanied by chills

While these symptoms may not demand immediate medical attention, scheduling an appointment with a healthcare professional to address the underlying issue is crucial. Certain circumstances warrant urgent medical care for both healing and safety. Seek immediate attention if you experience:

  • Severe pain accompanied by vomiting, fever, and/or chills
  • Visible blood in the urine
  • Difficulty urinating

Timely consultation with a healthcare provider ensures appropriate intervention and management of kidney stones.

Suffering from a kidney stone? Get a prescription for Flomax with Your Doctors Online.

FAQs about Flomax for kidney stone

How do I manage the side effects of dizziness with Flomax?

Flomax or tamsulosin may have side effects like sweating and dizziness, which you can overcome by changing your position from sitting to standing and vice versa until you feel better. Refrain from driving, cycling, or operating machinery while experiencing dizziness. Avoid alcohol consumption, as it can exacerbate these symptoms.

Is it safe to continue Flomax if I have other medical conditions?

Flomax (tamsulosin) interacts with 289 drugs, has four disease interactions, and involves two alcohol/food interactions. Among these interactions, 32 are considered major, 253 moderate, and four minor. Considering these potential interactions, discussing the safety of continuing Flomax with your healthcare provider is imperative.

Can I take Flomax if I’m pregnant or breastfeeding?

Flomax is not recommended for use in women and is unlikely to be prescribed during pregnancy or breastfeeding.

Is it common to experience Flomax not working for me?

Response to Flomax varies among individuals, and not everyone may find it effective. Those who continue to experience persistent urges to urinate or other urinary symptoms should consult their healthcare providers. Alternative medications, a combination of drugs, or lifestyle adjustments may be explored to improve symptoms.

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Is Flomax Effective for Kidney Stones?

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