Flomax Side Effects
Generic name: tamsulosin
Note: This document contains side effect information about tamsulosin. Some of the dosage forms listed on this page may not apply to the brand name Flomax.
Some side effects of Flomax may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to tamsulosin: oral capsule
Get emergency medical help if you have any of these signs of an allergic reaction while taking tamsulosin (the active ingredient contained in Flomax) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using tamsulosin and call your doctor at once if you have any of these serious side effects:
feeling like you might pass out;
fever, chills, body aches, or flu symptoms; or
penis erection that is painful or lasts 4 hours or longer.
Less serious side effects of tamsulosin may include:
sleep problems (insomnia);
abnormal ejaculation, decreased sex drive; or
runny nose, sore throat, cough.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.
For Healthcare Professionals
Applies to tamsulosin: oral capsule
In one case report, seizure frequency increased in a patient with medial temporal lobe seizures following initiation of tamsulosin (the active ingredient contained in Flomax) treatment. Prior to the use of tamsulosin, the patient experienced 3 to 4 seizures per year. In the first 3 months after starting tamsulosin, seizures were appearing twice a month and by the fourth month of treatment the patient had 3 seizures in one day. Following withdrawal of tamsulosin, seizure frequency returned to baseline.
Nervous system side effects are among the most common and include headache in 4% to 20%, asthenia in 1% to 8%, dizziness in 5% to 15%, somnolence in 0% to 4%, and insomnia in 1% to 2% of patients. (These side effects were also noted among patients treated with placebo in controlled trials, but occurred more often among patients treated with tamsulosin.) According to one case report, tamsulosin caused exacerbation of seizures in a patient with a history of seizures.
Abnormal ejaculation includes ejaculation failure, ejaculation disorder, retrograde ejaculation and ejaculation decrease. In controlled studies, abnormal ejaculation was associated with the use of tamsulosin (the active ingredient contained in Flomax) and was dose-related. The results of one study suggest that intermittent use of tamsulosin may allow for improvement in abnormal ejaculation.
Genitourinary complaints include abnormal (retrograde or decreased volume) ejaculation among 8% (0.4 mg) to 18% (0.8 mg) of male patients. The occurrence of abnormal ejaculation among males who were given placebo in controlled trials averaged 0.2%. Other genitourinary side effects have included impotence (2.9%) and rare cases of urinary retention and priapism.
Respiratory system side effects include rhinitis in 1% to 18%, pharyngitis in 5%, increased cough in 4%, and sinusitis in 3% of patients. In controlled studies, these side effects were also noted in similar but slightly lower incidences among patients who were treated with placebo.
Musculoskeletal complaints--back or chest pains--were reported among 4% to 8% of patients in controlled trials, compared with 4% to 7% among patients who were treated with placebo.
Rarely, flushing and tachycardia have been associated with the use of tamsulosin (the active ingredient contained in Flomax)
Cardiovascular side effects including rare occurrences of orthostatic hypotension have been reported. In two US studies, symptomatic postural hypotension was reported by 0.2% (0.4 mg), 0.4% (0.8 mg), and 0% (placebo) of patients. Syncope was reported by 0.2%, 0.4%, and 0.6% of patients in the above groups, respectively. Because of the risk of syncope, it is recommended that patients be warned against situations where injury could result were syncope to occur.
Gastrointestinal side effects include diarrhea in 5% and nausea in 3% of patients. In controlled studies, these side effects were also noted in similar but slightly lower incidences among patients who were treated with placebo. Rarely, constipation, gastric pain, dysphagia, and anorexia have been associated with the use of tamsulosin (the active ingredient contained in Flomax)
Although the overall prevalence of intraoperative floppy iris syndrome (IFIS) is 1% to 2%, the incidence of IFIS associated with the use of tamsulosin (the active ingredient contained in Flomax) ranges from 43% to 63%. Most reports were in patients treated with an alpha-1 blocker at the time IFIS occurred, but in some instances the alpha-1 blocker had been stopped prior to surgery. The manufacturer recommends that male patients be questioned to determine whether or not they have taken tamsulosin or other alpha-1 blockers prior to being considered for cataract surgery. If it is determined that the patient has taken an alpha-rt1 blocker, the patient's ophthalmologist should be prepared for possible modifications to their surgical technique that may be necessary should IFIS be observed during the procedure.
Clinical studies in men 66 years of age and older who were exposed to tamsulosin within 14 days of cataract surgery was significantly associated with serious postoperative ophthalmic adverse events other than IFIS.
Ocular side effects including amblyopia have been reported in 0.2% of men given 0.4 mg, 2% of men given 0.8 mg, and in 0.4% of men who were given placebo.
Intraoperative Floppy Iris Syndrome (IFIS) has been observed in some patients undergoing phacoemulsification cataract surgery while being treated with alpha-1 blockers including tamsulosin.
Hepatic side effects including rare isolated instances of elevated liver function tests have been associated with the use of tamsulosin (the active ingredient contained in Flomax)
General side effects unrelated to a particular organ system include a flu-like syndrome or infection in approximately 2% of patients. (Similar incidences were observed among patients who were treated with placebo in controlled trials.)
More Flomax resources
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