Tamsulosin, the generic term for Flomax, is a medication that treats the symptoms associated with an enlarged prostate gland (benign prostatic hyperplasia, or BPH). These symptoms most commonly include difficult, painful or urgent urination. As an alpha blocker, tamsulosin works by relaxing the muscles around the prostate and bladder so that urine flows more easily. Like all drugs, tamsulosin may cause some adverse side effects. Although most of these side effects seem to be temporary, patients affected by intraoperative floppy iris syndrome (IFIS) may suffer long-term effects.
The most common side effects of tamsulosin affect the nervous system. Among men who take tamsulosin, 4 to 20 per cent will experience headaches, 1 to 8 per cent will suffer from weakness, and 5 to 15 per cent will experience dizziness. Additionally, up to 4 per cent of users will experience drowsiness and up to 2 per cent will develop insomnia. One study also indicates an increased likelihood of seizures in patients who have a history of seizures.
Abnormal ejaculation is a well-known side effect associated with the use of tamsulosin, with 8 to 18 per cent of males reporting retrograde or decreased volume of ejaculation. Other sexual side effects include an increased rate of impotence in roughly 3 per cent of patients, and rare cases of erections that last longer than four hours. These symptoms seem to be dose-related; decreasing the dosage of tamsulosin may reduce their occurrence.
The most commonly reported respiratory side effects include a stuffy nose (up to 18 per cent of users), cough (4 per cent) and sinusitis (3 per cent).
Tamsulosin's gastrointestinal side effects include diarrhoea in 5 per cent of patients and nausea in 3 per cent. In rare cases, the drug may cause constipation, gastrointestinal pain, difficulty swallowing and anorexia.
Although only 1 to 2 per cent of people experience intraoperative floppy iris syndrome (IFIS) during cataract surgery, 43 to 63 per cent of those cases are associated with alpha blockers such as tamsulosin. Patients affected by IFIS suffer from a flaccid iris that billows in response to ocular fluid. This complication may lead to more post-operative pain, a longer recovery time and less vision improvement. Therefore, a patient with a history of tamsulosin use should alert his ophthalmologist, so that she can adjust the patient's eye treatment accordingly.
In rare cases, tamsulosin users have reported flushing, increased heart rate (tachycardia) and temporary loss of consciousness (syncope).
In rare instances, researchers have noted elevated liver function --- which may indicate liver damage --- in patients using tamsulosin.