Flomax (tamsulosin HCl)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Tamsulosin hydrochloride is an alpha1-adrenergic blocking agent with selectivity for alpha1A-adrenergic receptors, which are mainly located in nonvascular smooth muscle (e.g., prostate).
Tamsulosin hydrochloride is a sulfamoylphenethylamine-derivative alpha1-adrenergic blocking agent. Commercially available tamsulosin hydrochloride is a racemic mixture of 2 isomers. The drug is pharmacologically related to doxazosin, prazosin, and terazosin; however, unlike these drugs, tamsulosin has higher affinity and selectivity for alpha1A-adrenergic receptors, which are mainly located in nonvascular smooth muscle (e.g., prostate), than for alpha1B-adrenergic receptors located in vascular smooth muscle (e.g., internal iliac artery).
Results of in vitro studies indicate that tamsulosin has 7-38 times greater affinity for alpha1A-adrenoceptors than for alpha1B-adrenoceptors; the drug has about 12 times greater affinity for alpha1-adrenergic receptors in the prostate than for those in the aorta. Such selectivity of tamsulosin for alpha1A-receptors may result in a reduced incidence of adverse cardiovascular effects (e.g., syncope, dizziness, hypotension). On a molar basis, the alpha1-adrenergic receptor affinity of tamsulosin is about 6 times that of prazosin when tested in human prostatic tissue.
Because of the prevalence of alpha-receptors on the prostate capsule, prostate adenoma, and bladder trigone and the relative absence of these receptors on the bladder body, alpha-adrenergic blocking agents decrease urinary outflow resistance in men.
SumMon(R) (see Users Guide). For additional information on this drug until a more detailed monograph is developed and published, the manufacturer's labeling should be consulted. It is essential that the labeling be consulted for detailed information on the usual cautions, precautions, and contraindications.
USES: Tamsulosin is used by men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia-BPH). It does not shrink the prostate, but it works by relaxing the muscles in the prostate and the bladder. This helps to relieve symptoms of BPH such as difficulty in beginning the flow of urine, weak stream, and the need to urinate often or urgently (including during the middle of the night).
Tamsulosin belongs to a class of drugs known as alpha blockers. Do not use this medication to treat high blood pressure.
Generic name: tamsulosin HCl
Pronunciation: (tam-SOO-loe-sin)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Flomax
Indications
The following indications are listed for Flomax:
- Benign Prostatic Hyperplasia With Lower Urinary Tract Symptom
Also known as: Symptomatic Benign Prostatic Hyperplasia, Symptomatic Benign Prostatic Hypertrophy, Symptomatic Bph, Symptomatic Prostatic Hypertrophy.
Dosing
The manufacturer states that safety and efficacy of tamsulosin in children younger than 18 years of age have not been established, and clinical experience in these patients is not available.
Although protein binding of tamsulosin may be altered in patients with mild to moderate (i.e., creatinine clearance of 30-70 mL/minute per 1.73 m2) or severe (i.e., creatinine clearance of 10 to less than 30 mL/minute per 1.73 m2) renal impairment and in patients with moderate hepatic impairment resulting in changes of overall plasma concentrations of the drug, alterations in intrinsic clearance and concentrations of unbound tamsulosin do not appear to be substantial. Therefore, the manufacturer states that dosage adjustment in such patients is not necessary. However, tamsulosin has not been studied in patients with end-stage (i.e., creatinine clearance of less than 10 mL/minute per 1.73 m2) renal disease.
Tamsulosin is administered orally. Because food may decrease peak plasma concentrations of tamsulosin and lengthen the time to achievement of peak plasma concentrations and decrease oral bioavailability of the drug, the manufacturer recommends that tamsulosin be taken 30 minutes after a meal; it is recommended that the drug be taken after the same meal each day. Patients should be advised that the capsules must be swallowed intact and not be opened, chewed, or crushed.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
There is no enhanced messaging for this drug.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
Known hypersensitivity to tamsulosin or any ingredient in the formulation.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
Headache, infection, asthenia, back pain, chest pain, dizziness, somnolence, insomnia, decreased libido, rhinitis, pharyngitis, increased cough, sinusitis, diarrhea, nausea, tooth disorder, abnormal ejaculation, blurred vision.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
No enhanced messaging available.
Not indicated for use in children.
Category B. Not indicated for use in women.
Not indicated for use in women.
No substantial differences in safety and efficacy relative to younger adults, but increased sensitivity cannot be ruled out.
ICD codes
No ICD codes are available for this drug.
Formulary status
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Last reviewed · Source: First Databank (FDB) drug data
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