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Flomax

Last reviewed on RxList: 5/27/2020
Flomax Side Effects Center

What Is Flomax

Flomax (tamsulosin hydrochloride) is an alpha-blocker used to treat the symptoms of a prostate gland condition called BPH (benign prostatic hyperplasia). Flomax is available as a generic drug.

What Are Side Effects of Flomax

Common side effects of Flomax include:

Tell your doctor if you experience serious side effects of Flomax including

  • an erection that is painful or lasts more than four hours,
  • severe dizziness, or
  • fainting.

Dosage for Flomax

Flomax capsules 0.4 mg once daily is recommended as the dose for the treatment of the signs and symptoms of BPH and dosing should be taken by mouth, usually once daily.

  • Take the first dose at bedtime to minimize the chances of getting dizzy or fainting.
  • After the first dose, take your regularly scheduled dose 30 minutes after the same meal each day.

What Drugs, Substances, or Supplements Interact with Flomax

  • Drug interaction and warnings include that Flomax capsules should not be used in combination with other alpha andrenergic blocking agents.
  • It should not be used in combination with strong inhibitors of CYP3A4 (e.g., ketoconazole).
  • Flomax should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin) and with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6.
  • Flomax should also be used with caution in combination with cimetidine.
  • Caution should be exercised with concomitant administration of warfarin and Flomax capsules.

Flomax and Pregnancy

  • Flomax is not indicated for use in women and is unlikely to be used during pregnancy or while breastfeeding.
  • If a patient reports a serious, life-threatening sulfa allergy, caution is warranted when administering Flomax capsules.
  • Additional Information

    Our Flomax Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

    This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

    QUESTION

    The prostate is about the size of a _____________. See Answer
    Flomax Consumer Information

    Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

    Stop using tamsulosin and call your doctor at once if you have:

    • a light-headed feeling, like you might pass out; or
    • penis erection that is painful or lasts 4 hours or longer.

    Tamsulosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it. You may feel very dizzy when you first wake up. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

    Common side effects may include:

    • abnormal ejaculation, decreased amount of semen;
    • dizziness, drowsiness, weakness;
    • runny nose, cough;
    • back pain, chest pain;
    • nausea, diarrhea;
    • tooth problems;
    • blurred vision;
    • sleep problems (insomnia); or
    • decreased interest in sex.

    This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

    Read the entire detailed patient monograph for Flomax (Tamsulosin Hydrochloride)

    SLIDESHOW

    Prostate Cancer Symptoms, PCA Test, Treatments See Slideshow
    Flomax Professional Information

    SIDE EFFECTS

    Clinical Trials Experience

    Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The incidence of treatment-emergent adverse events has been ascertained from six short-term U.S. and European placebo-controlled clinical trials in which daily doses of 0.1 to 0.8 mg FLOMAX capsules were used. These studies evaluated safety in 1783 patients treated with FLOMAX capsules and 798 patients administered placebo. Table 1 summarizes the treatment-emergent adverse events that occurred in ≥2% of patients receiving either FLOMAX capsules 0.4 mg or 0.8 mg and at an incidence numerically higher than that in the placebo group during two 13-week U.S. trials (US92-03A and US93-01) conducted in 1487 men.

    Table 1: Treatment-Emergent* Adverse Events Occurring in ≥2% of FLOMAX Capsules or Placebo Patients in Two U.S. Short-Term Placebo-Controlled Clinical Studies

    BODY SYSTEM/ ADVERSE EVENT FLOMAX CAPSULES GROUPS PLACEBO
    0.4 mg
    n=502
    0.8 mg
    n=492
    n=493
    BODY AS WHOLE
    Headache 97 (19.3%) 104 (21.1%) 99 (20.1%)
    Infection† 45 (9.0%) 53 (10.8%) 37 (7.5%)
    Asthenia 39 (7.8%) 42 (8.5%) 27 (5.5%)
    Back pain 35 (7.0%) 41 (8.3%) 27 (5.5%)
    Chest pain 20 (4.0%) 20 (4.1%) 18 (3.7%)
    NERVOUS SYSTEM
    Dizziness 75 (14.9%) 84 (17.1%) 50 (10.1%)
    Somnolence 15 (3.0%) 21 (4.3%) 8 (1.6%)
    Insomnia 12 (2.4%) 7 (1.4%) 3 (0.6%)
    Libido decreased 5 (1.0%) 10 (2.0%) 6 (1.2%)
    RESPIRATORY SYSTEM
    Rhinitis‡ 66 (13.1%) 88 (17.9%) 41 (8.3%)
    Pharyngitis 29 (5.8%) 25 (5.1%) 23 (4.7%)
    Cough increased 17 (3.4%) 22 (4.5%) 12 (2.4%)
    Sinusitis 11 (2.2%) 18 (3.7%) 8 (1.6%)
    DIGESTIVE SYSTEM
    Diarrhea 31 (6.2%) 21 (4.3%) 22 (4.5%)
    Nausea 13 (2.6%) 19 (3.9%) 16 (3.2%)
    Tooth disorder 6 (1.2%) 10 (2.0%) 7 (1.4%)
    UROGENITAL SYSTEM
    Abnormal ejaculation 42 (8.4%) 89 (18.1%) 1 (0.2%)
    SPECIAL SENSES
    Blurred vision 1 (0.2%) 10 (2.0%) 2 (0.4%)
    *A treatment-emergent adverse event was defined as any event satisfying one of the following criteria:
    The adverse event occurred for the first time after initial dosing with double-blind study medication.
    The adverse event was present prior to or at the time of initial dosing with double-blind study medication and subsequently increased in severity during double-blind treatment; or
    The adverse event was present prior to or at the time of initial dosing with double-blind study medication, disappeared completely, and then reappeared during double-blind treatment.
    †Coding preferred terms also include cold, common cold, head cold, flu, and flu-like symptoms.
    ‡Coding preferred terms also include nasal congestion, stuffy nose, runny nose, sinus congestion, and hay fever.

    Signs And Symptoms Of Orthostasis

    In the two U.S. studies, symptomatic postural hypotension was reported by 0.2% of patients (1 of 502) in the 0.4 mg group, 0.4% of patients (2 of 492) in the 0.8 mg group, and by no patients in the placebo group. Syncope was reported by 0.2% of patients (1 of 502) in the 0.4 mg group, 0.4% of patients (2 of 492) in the 0.8 mg group, and 0.6% of patients (3 of 493) in the placebo group. Dizziness was reported by 15% of patients (75 of 502) in the 0.4 mg group, 17% of patients (84 of 492) in the 0.8 mg group, and 10% of patients (50 of 493) in the placebo group. Vertigo was reported by 0.6% of patients (3 of 502) in the 0.4 mg group, 1% of patients (5 of 492) in the 0.8 mg group, and by 0.6% of patients (3 of 493) in the placebo group.

    Multiple testing for orthostatic hypotension was conducted in a number of studies. Such a test was considered positive if it met one or more of the following criteria: (1) a decrease in systolic blood pressure of ≥20 mmHg upon standing from the supine position during the orthostatic tests; (2) a decrease in diastolic blood pressure ≥10 mmHg upon standing, with the standing diastolic blood pressure <65 mmHg during the orthostatic test; (3) an increase in pulse rate of ≥20 bpm upon standing with a standing pulse rate ≥100 bpm during the orthostatic test; and (4) the presence of clinical symptoms (faintness, lightheadedness/lightheaded, dizziness, spinning sensation, vertigo, or postural hypotension) upon standing during the orthostatic test.

    Following the first dose of double-blind medication in Study 1, a positive orthostatic test result at 4 hours post-dose was observed in 7% of patients (37 of 498) who received FLOMAX capsules 0.4 mg once daily and in 3% of the patients (8 of 253) who received placebo. At 8 hours post-dose, a positive orthostatic test result was observed for 6% of the patients (31 of 498) who received FLOMAX capsules 0.4 mg once daily and 4% (9 of 250) who received placebo (Note: patients in the 0.8 mg group received 0.4 mg once daily for the first week of Study 1).

    In Studies 1 and 2, at least one positive orthostatic test result was observed during the course of these studies for 81 of the 502 patients (16%) in the FLOMAX capsules 0.4 mg once-daily group, 92 of the 491 patients (19%) in the FLOMAX capsules 0.8 mg once-daily group, and 54 of the 493 patients (11%) in the placebo group.

    Because orthostasis was detected more frequently in FLOMAX capsule-treated patients than in placebo recipients, there is a potential risk of syncope [see WARNINGS AND PRECAUTIONS].

    Abnormal Ejaculation

    Abnormal ejaculation includes ejaculation failure, ejaculation disorder, retrograde ejaculation, and ejaculation decrease. As shown in Table 1, abnormal ejaculation was associated with FLOMAX capsules administration and was dose-related in the U.S. studies. Withdrawal from these clinical studies of FLOMAX capsules because of abnormal ejaculation was also dose-dependent, with 8 of 492 patients (1.6%) in the 0.8 mg group and no patients in the 0.4 mg or placebo groups discontinuing treatment due to abnormal ejaculation.

    Laboratory Tests

    No laboratory test interactions with FLOMAX capsules are known. Treatment with FLOMAX capsules for up to 12 months had no significant effect on prostate-specific antigen (PSA).

    Postmarketing Experience

    The following adverse reactions have been identified during post-approval use of FLOMAX capsules. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Decisions to include these reactions in labeling are typically based on one or more of the following factors: (1) seriousness of the reaction, (2) frequency of reporting, or (3) strength of causal connection to FLOMAX capsules. Allergic-type reactions such as skin rash, urticaria, pruritus, angioedema, and respiratory symptoms have been reported with positive rechallenge in some cases. Priapism has been reported rarely. Infrequent reports of dyspnea, palpitations, hypotension, atrial fibrillation, arrhythmia, tachycardia, skin desquamation including reports of Stevens-Johnson syndrome, erythema multiforme, dermatitis exfoliative, constipation, vomiting, dry mouth, visual impairment, and epistaxis have been received during the postmarketing period. During cataract and glaucoma surgery, a variant of small pupil syndrome known as Intraoperative Floppy Iris Syndrome (IFIS) has been reported in association with alpha1 blocker therapy [see WARNINGS AND PRECAUTIONS].

    Read the entire FDA prescribing information for Flomax (Tamsulosin Hydrochloride)

    Related Resources for Flomax

    Read the Flomax User Reviews »

    © Flomax Patient Information is supplied by Cerner Multum, Inc. and Flomax Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

    QUESTION

    The prostate is about the size of a _____________. See Answer

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