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Pharmacologic class: Alpha-adrenergic blocker
Therapeutic class: Anti-adrenergic
Pregnancy risk category B
Decreases smooth muscle contractions of prostate by binding to alpha1-adrenergic receptors. This action increases urine flow and reduces symptoms of benign prostatic hyperplasia (BPH).
Capsules: 0.4 mg
Indications and dosages
Adults: 0.4 mg/day P.O. after a meal. After 2 to 4 weeks, may increase to 0.8 mg/day.
• Hypersensitivity to drug or its components
Use cautiously in:
• concurrent use of other alpha-adrenergic blockers or strong CYP3A4 inhibitors (avoid use)
• concurrent use of moderate CYP3A4 inhibitors, strong or moderate CYP2D6 inhibitors, other cytochrome P450 inhibitors, warfarin, and in patients who are poor CYP2D6 metabolizers
• patients at increased risk for prostate cancer.
• Give 30 minutes after same meal each day.
CNS: dizziness, headache, asthenia, insomnia, drowsiness, syncope, vertigo
CV: orthostatic hypotension, chest pain
EENT: rhinitis, amblyopia, pharyngitis, sinusitis
GU: retrograde or diminished ejaculation, decreased libido
Musculoskeletal: back pain
Respiratory: increased cough
Other: tooth disorder, infection
Drug-drug. Cimetidine: increased tamsulosin blood level, greater risk of toxicity
Doxazosin, prazosin, terazosin: increased risk of hypotension
Ketoconazole (strong CYP3A4 inhibitor), paroxetine (strong CYP2D6 inhibitor): increased tamsulosin Cmax and area under the curve
Drug-behaviors. Alcohol use: increased risk of hypotension
• Monitor blood pressure. Stay alert for orthostatic hypotension.
• Tell patient to take 30 minutes after same meal each day.
• Instruct patient not to chew or open capsule. Advise him to swallow it whole.
• Tell patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from sudden blood pressure decrease.
• Caution patient to avoid hazardous activities on first day of therapy.
• Inform patient that drug may cause abnormal ejaculation. Advise him to discuss this issue with prescriber.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and behaviors mentioned above.
ClassificationTherapeutic: none assigned
Pharmacologic: peripherally acting antiadrenergics
Time/action profile (↑ in urine flow)
Adverse Reactions/Side Effects
Central nervous system
- dizziness (most frequent)
- headache (most frequent)
Ear, Eye, Nose, Throat
- orthostatic hypotension
- retrograde/diminished ejaculation
Drug-Drug interactionCimetidine may ↑ blood levels and the risk of toxicity.↑ risk of hypotension with other peripherally acting anti-adrenergics (doxazosin, prazosin, terazosin ); concurrent use should be avoided.↑ risk of hypotension with sildenafil, tadalafil, and vardenafil.Strong CYP3A4 inhibitors and CYP2D6 inhibitors may ↑ blood levels (concurrent use should be avoided.
Availability (generic available)
- Assess patient for symptoms of prostatic hyperplasia (urinary hesitancy, feeling of incomplete bladder emptying, interruption of urinary stream, impairment of size and force of urinary stream, terminal urinary dribbling, straining to start flow, dysuria, urgency) before and periodically during therapy.
- Assess patient for first-dose orthostatic hypotension and syncope. Incidence may be dose related. Observe patient closely during this period and take precautions to prevent injury.
- Monitor intake and output ratios and daily weight, and assess for edema daily, especially at beginning of therapy. Report weight gain or edema.
- Rectal exams prior to and periodically throughout therapy to assess prostate size are recommended.
Potential Nursing DiagnosesRisk for injury (Side Effects)
Impaired urinary elimination (Indications)
- Oral: Administer daily dose 30 min after the same meal each day. Swallow capsules whole; do not open, crush, or chew.
- If dose is interrupted for several days at either the 0.4-mg or 0.8-mg dose, restart therapy with the 0.4-mg/day dose.
- Emphasize the importance of continuing to take this medication, even if feeling well. Instruct patient to take medication at the same time each day. If a dose is missed, take as soon as remembered unless almost time for next dose. Do not double doses.
- May cause dizziness. Advise patient to avoid driving or other activities requiring alertness until response to medication is known.
- Caution patient to change positions slowly to minimize orthostatic hypotension.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications, especially cough, cold, or allergy remedies.
- Emphasize the importance of follow-up visits to determine effectiveness of therapy.
- Decrease in urinary symptoms of benign prostatic hyperplasia.
Flomax®Tamsolusin Urology An alpha blocker used to manage BPH, which can be used with antihypertensives, to manage hyperlipidemia Adverse effects Headache, infection, asthenia, dizziness. See Benign prostatic hypertrophy.
Patient discussion about Flomax
Q. Should FloMax & Avodart be taken together? Been on Avodart for 5 Mos.FloMax 3yrs.