Tamsulosin Hydrochloride

Pronunciation

Class: Selective alpha-1-Adrenergic Blocking Agents
ATC Class: G04CA02
VA Class: CV150
Chemical Name: (R)-5-[2-[[2-(2-ethoxyphenoxy)ethyl]amino]propyl] -2-methoxybenzenesulfonamide monohydrochloride
Molecular Formula: C20H28N2O5S•HCl
CAS Number: 106463-17-6
Brands: Flomax

Introduction

α1-Adrenergic blocking agent with selectivity for α1A-adrenergic receptors; sulfamoylphenethylamine derivative.1 2 3 5 6 8 9 10 11 12 13 14 15 32 33

Uses for Tamsulosin Hydrochloride

Benign Prostatic Hyperplasia (BPH)

Reduction of urinary obstruction and relief of associated manifestations (e.g., hesitancy, terminal dribbling of urine, interrupted or weak stream, impaired size and force of stream, sensation of incomplete bladder emptying or straining) in hypertensive or normotensive patients with symptomatic BPH.1 2 3 5 6 8 9 10 11 12 13 14 15 35

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Although drug therapy usually is not as effective as surgical therapy, it may provide adequate symptomatic relief with fewer and less serious adverse effects compared with surgery.35

May consider combined therapy with an α1-adrenergic blocker and 5α-reductase inhibitor for men with bothersome moderate to severe BPH and demonstrable prostatic enlargement.35 Has been more effective than therapy with either drug alone in preventing long-term BPH symptom progression.35 Men at risk for BPH progression are most likely to benefit from combination therapy.35

Other Uses

Manufacturer states that tamsulosin should not be used for the treatment of hypertension.1

Tamsulosin Hydrochloride Dosage and Administration

Administration

Oral Administration

Administer orally once daily, 30 minutes after the same meal each day.1 8

Swallow capsules intact; do not open, crush, or chew capsules.1

Dosage

Available as tamsulosin hydrochloride; dosage expressed in terms of the salt.1

Adults

BPH
Oral

Initially, 0.4 mg once daily.1 Allow 2–4 weeks to assess response at initial dosage.1 May increase dosage to 0.8 mg once daily, if necessary, to improve urinary flow rates and reduce symptoms.1

If administration is interrupted for several days at either dosage (i.e., 0.4 or 0.8 mg daily), reinitiate therapy at dosage of 0.4 mg once daily.1

Special Populations

Hepatic Impairment

Dosage adjustment not necessary in patients with moderate hepatic impairment.1

Renal Impairment

Dosage adjustment not necessary in patients with mild to severe renal impairment (Clcr 10–70 mL/minute per 1.73 m2).1

Not studied in patients with end-stage renal disease (Clcr <10 mL/minute per 1.73 m2).1

Cautions for Tamsulosin Hydrochloride

Contraindications

  • Known hypersensitivity to tamsulosin or any ingredient in the formulation.1

Warnings/Precautions

Warnings

Postural Hypotension

Potential for postural hypotension, dizziness, or vertigo; syncope may occur.1

Priapism

Priapism reported rarely; treat promptly.1

Sensitivity Reactions

Allergic Reactions

Rash, pruritus, urticaria, and angioedema of the tongue, lips, and face reported; positive rechallenge in some patients.1

Sulfonamide Sensitivity

Allergic reaction to tamsulosin reported rarely in patients with sulfonamide sensitivity.1 Use with caution in patients with serious or life-threatening sulfonamide sensitivity.1

General Precautions

Prostate Cancer

Exclude possibility of prostate cancer prior to initiation of therapy.1

Intraoperative Floppy Iris Syndrome (IFIS)

IFIS observed during phacoemulsification cataract surgery in some patients receiving α1-blockers, including tamsulosin.1 36 Most cases were in patients who continued tamsulosin therapy at the time of cataract surgery.1 36

Specifically question male patients being considered for cataract surgery to ascertain whether they have received tamsulosin or other α1-blockers.36 If patient has received tamsulosin, ophthalmologist should be prepared for possible modifications to his/her surgical technique (e.g., use of iris hooks, iris dilator rings, viscoelastic substances) to minimize complications of IFIS.1 36

Benefit of discontinuing α1-blockers, including tamsulosin, prior to cataract surgery not established.1 36

Specific Populations

Pregnancy

Category B.1 Not indicated for use in women.1

Lactation

Not indicated for use in women.1

Pediatric Use

Not indicated for use in children.1

Geriatric Use

No substantial differences in safety and efficacy relative to younger adults, but increased sensitivity cannot be ruled out.1

Common Adverse Effects

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.1

Interactions for Tamsulosin Hydrochloride

Specific Drugs

Drug

Interaction

Comments

α-Adrenergic blocking agents

Additive effects1

Concomitant use not recommended1

Atenolol

No change in BP or pulse rate1

Dosage adjustment not necessary1

Cimetidine

Increased plasma tamsulosin concentrations1

Use with caution, particularly with doses >0.4 mg1

Digoxin

Pharmacokinetic interaction unlikely1

Enalapril

No change in BP or pulse rate1

Dosage adjustment not necessary1

Furosemide

Decreased plasma tamsulosin concentrations1

Not clinically important1

Nifedipine

No change in BP or pulse rate1

Dosage adjustment not necessary1

Theophylline

Pharmacokinetic interaction unlikely1

Warfarin

Possible pharmacokinetic interaction1

Available data inconclusive; use with caution1

Tamsulosin Hydrochloride Pharmacokinetics

Absorption

Bioavailability

Essentially completely absorbed following oral administration under fasting conditions; peak plasma concentrations attained within 4–5 hours.1

Food

Food delays time to peak plasma concentration by about 2 hours.1 When administered under fasting conditions, bioavailability and peak plasma concentration are increased by 30 and 40–70%, respectively, compared with fed state.1

Distribution

Extent

Appears to distribute into extracellular fluids in humans.1 In animals, distributed into kidney, prostate, liver, gallbladder, heart, aorta, and brown fat, with minimal distribution into brain, spinal cord, and testes.1

Plasma Protein Binding

94–99% (mainly to α1-acid glycoprotein).1

Special Populations

In patients with moderate hepatic impairment, protein binding is altered, resulting in changes in overall plasma concentrations; however, no substantial alterations in intrinsic clearance and concentrations of unbound drug.1 8 13

In patients with renal impairment, protein binding is altered, resulting in changes in overall plasma concentrations; however, no substantial alterations in intrinsic clearance and concentrations of unbound drug.1 8 13

Elimination

Metabolism

Extensively metabolized by CYP enzymes (specific isoenzyme[s] not identified) in the liver.1 Metabolites undergo further conjugation prior to excretion.1

Elimination Route

Excreted in urine (76%) and feces (21%).1

Half-life

Because of absorption rate-controlled pharmacokinetics of tamsulosin capsules, apparent half-life is about 9–13 hours in healthy individuals and 14–15 hours in patients with BPH.1

Special Populations

In males 55–75 years of age, intrinsic clearance is decreased and elimination half-life is prolonged, resulting in a 40% increase in AUC compared with males 20–32 years of age.1 34

Stability

Storage

Oral

Capsules

25°C (may be exposed to 15–30°C).1

Actions

  • Binds to α1-adrenergic receptors on the prostate and the bladder trigone, resulting in decreased urinary outflow resistance in men.2 5 8 9 11 12

  • Higher affinity for α1A-adrenergic receptors, which are located in nonvascular smooth muscle (e.g., prostate), than for α1B-adrenergic receptors located in vascular smooth muscle (e.g., internal iliac artery);1 8 9 10 11 12 33 may result in reduced incidence of cardiovascular effects (e.g., syncope, dizziness, hypotension).8 9 10 11 12 13

Advice to Patients

  • Importance of providing patient a copy of manufacturer’s patient information and advising patient to read and follow instructions for use.1

  • Risk of feeling faint or dizzy, particularly following initiation of therapy or dosage increase; avoid operating machinery or driving a motor vehicle for 12 hours following initial dose or dosage increase.1

  • Importance of sitting or lying down when symptoms of lowered BP occur and of rising carefully from a sitting or lying position.1

  • Importance of advising male patients being considered for cataract surgery that they should inform their ophthalmologist of current or prior α1-blocker therapy.1

  • Importance of men seeking medical treatment promptly if an erection is painful or persists for several hours.1

  • Importance of taking tamsulosin 30 minutes after the same meal each day.1 Importance of swallowing the capsules whole and of not chewing, crushing, or opening the capsules.1

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs.1

  • Importance of informing patients of other important precautionary information.1 (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Tamsulosin Hydrochloride

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Capsules

0.4 mg

Flomax

Boehringer Ingelheim

Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 02/2014. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.

Flomax 0.4MG Capsules (BOEHRINGER INGELHEIM): 30/$153.99 or 90/$431.95

Jalyn 0.5-0.4MG Capsules (GLAXO SMITH KLINE): 30/$129.00 or 90/$369.96

Tamsulosin HCl 0.4MG Capsules (ZYDUS PHARMACEUTICALS (USA)): 30/$122.99 or 90/$328.98

AHFS DI Essentials. © Copyright, 2004-2014, Selected Revisions June 9, 2011. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

References

1. Boehringer Ingelheim. Flomax (tamsulosin hydrochloride) capsules prescribing information. Ridgefield, CT; 2006 Jul 19.

2. Geller J, Kirschenbaum A, Lepor H et al. Therapeutic controversies: clinical treatment of benign prostatic hyperplasia. J Clin Endocrinol Metab. 1995; 80:745-53. [IDIS 348873] [PubMed 7533770]

3. Oesterling JE. Benign prostatic hyperplasia: medical and minimally invasive treatment options. N Engl J Med. 1995; 332:99-109. [IDIS 340651] [PubMed 7527494]

4. Nacey J, Delahunt B. Changing perspectives in benign prostatic hyperplasia. N Z Med J. 1995; 108:283-4. [IDIS 352161] [PubMed 7543666]

5. Kawabe K, Ueno A, Takimoto Y et al et al. Use of an α1-blocker, YM617, in the treatment of benign prostatic hypertrophy. J Urol. 1990; 144:908-12. [IDIS 275219] [PubMed 1697914]

6. Eri LM, Tveter KJ. α-blockade in the treatment of symptomatic benign prostatic hyperplasia. J Urol. 1995; 154:923-34. [IDIS 351642] [PubMed 7543612]

7. Narayan P, Indudhara R. Pharmacotherapy for benign prostatic hyperplasia. West J Med. 1994; 161:495-506. [IDIS 338686] [PubMed 7528957]

8. Wilde MI, McTavish D. Tamsulosin: a review of its pharmacological properties and therapeutic potential in the management of symptomatic benign prostatic hyperplasia. Drugs. 1996; 52:883-98. [PubMed 8957159]

9. Chapple CR, Wyndaele JJ, Nordling J et al et al. Tamsulosin, the first prostate-selective α1A-adrenoceptor antagonist: a meta-analysis of two randomized, placebo-controlled, multicentre studies in patients with benign prostatic obstruction (symptomatic BPH). Eur Urol. 1996; 29:155-67. [PubMed 8647141]

10. Hieble JP, Ruffolo RR Jr. The use of α-adrenoceptor antagonists in the pharmacological management of benign prostatic hypertrophy: an overview. Pharmacol Res. 1996; 33:145-60. [PubMed 8880886]

11. Schulman CC, Cortvriend J, Jonas U et al. Tamsulosin, the first prostate-selective α1A-adrenoceptor antagonist: analysis of a multinational, multicentre, open-label study assessing the long-term efficacy and safety in patients with benign prostatic obstruction (symptomatic BPH). Eur Urol. 1996; 29:145-54. [PubMed 8647140]

12. Abrams P, Schulman CC, Vaage S and the European Tamsulosin Study Group. Tamsulosin, a selective α1c-adrenoceptor antagonist: a randomized, controlled trial in patients with benign prostatic ’obstruction’ (symptomatic BPH). Br J Urol. 1995; 76:325-336. [PubMed 7551841]

13. Rabasseda X, Fitzpatrick JM. Tamsulosin: the first prostate-selective α1A-adrenoceptor antagonist for the treatment of symptomatic benign prostatic hyperplasia. Drugs Today. 1996; 32(Suppl C):1-12.

14. Lepor H and the Tamsulosin Investigator Group. Clinical evaluation of tamsulosin, a prostate selective alpha1c antagonist. J Urol. 1995; 153(Suppl):274A.

15. Lepor H and the Tamsulosin Investigator Group. Long-term evaluation of tamsulosin, a prostate selective alpha1 antagonist. J Urol. 1996; 155(Suppl):585A.

16. Wasson JH, Reda DJ, Bruskewitz RC et al et al. A comparison of transurethral surgery with watchful waiting for moderate symptoms of benign prostatic hyperplasia. N Engl J Med. 1995; 332:75-9. [PubMed 7527493]

17. Lepor H. The emerging role of alpha antagonists in the therapy of benign prostatic hyperplasia. J Androl. 1991; 12:389-94. [PubMed 1722795]

18. Wilde MI, Fitton A, Sorkin EM. Terazosin: a review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in benign prostatic hyperplasia. Drugs Aging. 1993; 3:258-77. [PubMed 7686794]

19. Lepor H, Meretyk S, Knapp-Maloney G. The safety, efficacy and compliance of terazosin therapy for benign prostatic hyperplasia. J Urol. 1992; 147:1554-7. [IDIS 297430] [PubMed 1375659]

20. Chapple C. Medical treatment for benign prostatic hyperplasia. BMJ. 1992; 304:1198-9. [IDIS 296671] [PubMed 1381250]

21. Chapple CR, Christmas TJ, Milroy EJG. A twelve-week placebo-controlled study of prazosin in the treatment of prostatic obstruction. Urol Int. 1990; 45(Suppl 1):47-55. [PubMed 1690482]

22. Lepor H. Role of long-acting selective alpha-1 blockers in the treatment of benign prostatic hyperplasia. Urol Clin North Am. 1990; 17:651-9. [PubMed 1695785]

23. Chisholm GD. Benign prostatic hyperplasia: the best treatment. BMJ. 1989; 299:215-6. [IDIS 257552] [PubMed 2475197]

24. Geller J. Nonsurgical treatment of prostatic hyperplasia. Cancer. 1992; 70(Suppl 1):339-45. [IDIS 298353] [PubMed 1376202]

25. Bostwick DG, Cooner WH, Denis L et al. The association of benign prostatic hyperplasia and cancer of the prostate. Cancer. 1992; 70(Suppl 1):291-301. [PubMed 1376199]

26. Hill SJ, Lawrence SL, Lepor H. New use for alpha blockers: benign prostatic hyperplasia. Am Fam Physician. 1994; 49:1885-8. [IDIS 330970] [PubMed 7515555]

27. Kirby RS. Alpha-adrenoceptor inhibitors in the treatment of benign prostatic hyperplasia. Am J Med. 1989; 87(Suppl 2A):26-30S.

28. Yamada S, Suzuki M, Tanaka C et al. Comparative study on α1-adrenoreceptor antagonist binding in human prostate and aorta. Clin Exp Pharmacol Physiol. 1994; 21:405-11. [PubMed 7955549]

29. Abbott Laboratories. Hytrin (terazosin hydrochloride) tablets prescribing information. North Chicago, IL; 1993 Aug.

30. Pfizer Roerig. Cardura (doxazosin mesylate) tablets prescribing information. New York, NY; 1994 Dec.

31. Hayashida S, Hirasawa T, Uchiyama K et al. Effect of tamsulosin hydrochloride on benign prostatic hyperplasia-comparison with prazosin hydrochloride. Proceedings of the 23rd Congress of the Societe Internationale d’Urologie. Sydney, Australia. 1994:99. Abstract No. 93.

32. Anon. Tamsulosin for benign prostatic hyperplasia. Med Lett Drugs Ther. 1997; 29:96.

33. Lowe FC. Coadministration of tamsulosin and three antihypertensive agents in patients with benign prostatic hyperplasia: pharmacodynamic effect. Clin Ther. 1997; 19:730-57. [IDIS 393050] [PubMed 9377617]

34. Reviewers’ comments (personal observations).

35. American Urological Association. Guideline on the management of benign prostatic hyperplasia (BPH)(2003/updated 2006). Available from website. Accessed 2006 Aug 10.

36. Boodee HW. Dear doctor letter regarding intraoperative floppy iris syndrome associated with tamsulosin. Ridgefield, CT: Boehringer Ingelheim; 2005 Nov.

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