Tamsulosin is a sulfamoylphen-ethylamine derivative, a potent and a selective antagonist of Alpha-1A adrenoceptor. It�s approved in the treatment of LUTS in BPH disease, being a specific Alpha -1A blocker it does not interfere much with the cardiovascular system. Though an age old molecule but still it�s a friendly drug to most of the physicians. Even the recent studies found its as efficacious to some of the newer molecules in the group

Praveen R, Int J Cur Bio Med Sci.

English

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Tamsulosin � turn a round

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Tamsulosin – Turn A Round: A Review
Praveen R
A R T I C L E I N F O A B S T R A C T
Keywords:
Original Article
Tamsulosin
Alpha 
Adrenoceptor
1. Introduction
2. Pharmacodynamic Properties
3.Urodynamic
4.Cardivascular System
5.Pharmacokinetics
Tamsulosin is a sulfamoylphen-ethylamine derivative, a potent and a selective antagonist of 
Alpha-1A adrenoceptor. It�s approved in the treatment of LUTS in BPH disease, being a 
specific Alpha -1A blocker it does not interfere much with the cardiovascular system. Though 
an age old molecule but still it�s a friendly drug to most of the physicians. Even the recent 
studies found its as efficacious to some of the newer molecules in the group.
      Tamsulosin is a sulfamoylphen-ethylamine derivative(Fig 1). It 
is a more potent and selective antagonist of Alpha-1A 
adrenoceptor. Tamsulosin  is a steroisomer. The binding of R (-) 
isomer is greater than that of S (+) isomer. The R (-) isomer is a 
modified release formulation is commercially available.     
Tamsulosin is a highly selective alpha1-adrenergic antagonist 
that was developed to avoid the side effects of nonselective 
agents.In the  new  nomenclature agreed upon  by the  
International Union  of Pharmacology the cloned  Alpha-1 
adrenoreceptor subtypes are Alpha-1A, Alpha-1B and Alpha-1D.1 
The messenger  RNA  expression  of Alpha-1A,Alpha-1D  subtypes 
are predominant  in the prostate  and the base and neck of the  
urinary bladder 2,3.
      The Alpha-1 adrenoreceptor subtypes selectively of tamsulosin 
was demonstrated to be Alpha-1A>Alpha-1D=Alpha-1B in exvivo 
radioceptor assays in placebo controlled, single blind, randomized, 
cross over study.
      The efficacy of tamsulosin is  by the blockade of Alpha-1A 
adrenoceptor in the prostate, there by relaxes the smooth muscles 
and results in the improvement of urinary flow rate4, 5, 6. It also 
contributes to the blockade of Alpha-1A, lpha-1D adrenoceptor in 
the bladder which inhibits the detrusor muscle instability and 
storage symptoms.7, 8,9 and may involve blockade of Alpha 
adrenoreceptors in the sympathetic nervous system and spinal 
cord.
      Unlike  other  Alpha blockers which are developed for treating  
hypertension, tamsulosin was specifically developed  for the  
treatment of LUTS in BPH.10 Significantly   less symptomatic  
11
orthostatic hypotension was documented  with tamsulosin .
Absorption of tamsulosin is gradual with a bio-availability of 
100 percent under fasting conditions.12 Fasting conditions 
increases the area under the tamsulosin plasma concentration- 
time curve by 30 percent and the mean maximum plasma 
concentration (cmax) by 40-70 percent compared with fed 
condition.
      Tamsulosin 0.4 mg when administerd with food, the maximum 
concentration (tmax) increases to 6 hours in contrast of 4 hours in 
Fasting conditions.
Copyright 2011. CurrentSciDirect Publications.  IJCBMS - All rights reserved.
Copyright 2011. CurrentSciDirect Publications.  IJCBMS - All rights reserved.
c
c
Kadhirnahalli, BSK IInd stage, Bangalore-70
*  Corresponding Author : Dr.Praveen R
No: 12, Balaji 4th cross, Kadhirnahalli,
BSK IInd stage,Bangalore-70
Cell: 9008149749
E.mail: drpraveen28@gmai.com
Contents lists available at SciDirect PublicationsCurrent
Journal homepage: www.currentscidirect.com
 International Journal of Current Biological and Medical Science
Int J Cur Bio Med Sci. 2011; 1(2): 39 – 40.
CurrentSciDirect
Publication
13
Tamsulosin is metabolized in the liver by CYP 450 enzyme , 
14.The primary iso-enzyme involved are CYP3A4 and 
CYP2D6.The metabolites do not play a major role in the efficacy of 
the drug. The clearance of tamsulosin is relatively slow 
13
(2.88L/hr) .Increased age diminishes the intrinsic clearance of 
tamsulosin, which results in slightly prolonged disposition of the 
13
drug in the elderly patient.
      After  a single dose administration of the modified  release 
tamsulosin 0.2 mg  in  healthy volunteers the elimination  half life 
15
was  9 hours .The modified  release  tamsulosin 0.4 mg is 
estimated  to be 14-15 hours in the elderly patients and  9 – 13 
13
hours in healthy volunters .
      Tamsulosin  improved  the symptom  score  to a greater  extent 
and also increased  Q max  when used  especially in patients  with  
mild to severe LUTS. The  reduction  in IPSS score  from base line 
in all groups of patients  with  LUTS.  In a recent study (2010) by 
Kawachi et al found that tamsulosin reduced the LUTS in patients 
suffering from BPH.15.
   Tamsulosin is well tolerated in the long term studies in the 
patients with LUTS regarding the age. The most common adverse 
effect occurred is abnormal ejaculation, the others are headache, 
15
dizziness, asthenia, rhinitis and orthostatic hypotension.
13,14,16 
Tamsulosin  is indicated  for the treatment  of  BPH. The 
usual dose is 0.4 mg/day  once daily after  the breakfast and the 
dose may be  increased to 0.8 mg once daily  for the patients who 
fail to respond  the 0.4mg dose after 2-4  weeks of treatment. The 
capsule should not be crushed  as this will interfere with the 
8,13 
modified  release  of tamsulosin It should be taken after the 
same meal  each day to produce  consistent plasma  drug  
concentration.
6.Therapeutic Efficacy
7.Tolerability
8.Dosage And Administration
9.References
Praveen R / Int J Cur Bio Med Sci. 2011; 1(2): 39 – 40.
[1] Hieble JP, Bylund DB, Clarke DE. International union of pharmacology X. 
Recommendation for nomenclature of alpha-adrenoceptors: consensus 
update.   J Pharmacol Rev 1994;47:267-270.  
[2] Roosen A, James B, Wood D, Fry C. Clinical and experimental aspects of 
A d r e n o - m u s c a r i n i c  s y n e r g y  i n  t h e  b l a d d e r  b a s e  a n d  
prostate.2009;28(8):938-943.
[3] Price DT, Schwinn DA, Lomasney JW. Identification, quantification, and 
localization of mRNA for three distinct alpha-1 adrenergic receptor 
subtypes in human prostate.J Urol 1993;150:546-551
[4] Holtgrewe HL. Current trends in management of men with lower urinary 
tract symptoms and benign prostatic hyperplasia. J Urol 1998;51:1-7.
[5]  Andersson  KE. Mode of action of alpha-adrenoreceptor antagonists in the 
treatment of lower urinary tract symptoms. BJU 2000;85:12-18.
[6] Puppo P. Do we know everything about alpha-blockade in the management 
of lower urinary tract symptoms?.J Eur Urol 2001;39:38-41.
[7] Schwinn DA, Michelotti GA. alpha-Adrenergic receptors in the lower 
urinary tract and vascular bed: potential role for the alpha subtype in filling 
symptoms and effects of ageing on vascular expression. BJU  2000;85:6-11.  
[8] Khoury S, Cockett A, Aso Y. International consultation on urological 
diseases: a decade of progress. J Prostate 2000;45:194-199
[9] Puppo P. Do we know everything about alpha-blockade in the management 
of lower urinary tract symptoms?. Eur Urol 2001 Jan; 39 Suppl. 2.: 38-41
[10] Beduschi MC, Beduschi R, Oesterling JE. Alpha-blockade therapy for benign 
prostatic hyperplasia: from a nonselective to a more selective alpha1A-
adrenergic antagonist. Urology 1998; 51: 861-72
[11] de Mey C, Michel MC, McEwen J, et al. A double-blind comparison of 
terazosin and tamsulosin on their differential effects on ambulatory blood 
pressure and nocturnal orthostatic stress testing. Eur Urol 1998; 33: 481-8
[12] van Hoogdalem EJ, Soeishi Y, Matsushima H, et al. Disposition of the 
selective [alpha]1A-adrenoceptor antagonist tamsulosin in humans: 
comparison with data from interspecies scaling. J Pharm Sci 1997; 86: 
1156-61
[13] Boehringer Ingelheim Pharmaceuticals Incorporated. Flomax 
(tamsulosin) prescribing information. 2000.
[14] Salinas F, Gabriela, Rosette J, Michel, Martin C. Pharmacokinetics and 
Pharmacodynamics of Tamsulosin in its Modified-Release and Oral 
Controlled Absorption System Formulations. 2010;49(3):177-88.  
[15] Kawachi Y, Sakurai T, Sugimura S, Iwata S, Noto K, Honda S et al. Long-term 
treatment and prognostic factors of α1-blockers for lower urinary tract 
symptoms associated with benign prostatic hyperplasia: A pilot study 
comparing naftopidil and tamsulosin hydrochloride.2010;44:38-45.
[16] Yamanouchi Pharmaceutical Co. Ltd. Harnal (tamsulosin) prescribing 
information. 2000 
Copyright 2011. CurrentSciDirect Publications.  IJCBMS - All rights reserved.c
39


A double-blind comparison of terazosin and tamsulosin on their differential effects on ambulatory blood pressure and nocturnal orthostatic stress testing. Eur Urol

alpha-Adrenergic receptors in the lower urinary tract and vascular bed: potential role for the alpha subtype in filling symptoms and effects of ageing on vascular expression.

Alpha-blockade therapy for benign prostatic hyperplasia: from a nonselective to a more selective alpha1Aadrenergic antagonist. Urology

Clinical and experimental aspects of A d r e n o - m u s c a r i n i c s y n e r g y i n t h e b l a d d e r b a s e a n d

Cur Bio Med Sci.

Current trends in management of men with lower urinary tract symptoms and benign prostatic hyperplasia.

Disposition of the selective [alpha]1A-adrenoceptor antagonist tamsulosin in humans: comparison with data from interspecies scaling.

Do we know everything about alpha-blockade in the management of lower urinary tract symptoms?. Eur Urol

Do we know everything about alpha-blockade in the management of lower urinary tract symptoms?.J Eur Urol

Harnal (tamsulosin) prescribing information.

International consultation on urological diseases: a decade of progress.

International union of pharmacology X. Recommendation for nomenclature of alpha-adrenoceptors: consensus update.

Long-term treatment and prognostic factors of α1-blockers for lower urinary tract symptoms associated with benign prostatic hyperplasia: A pilot study comparing naftopidil and tamsulosin

Mode of action of alpha-adrenoreceptor antagonists in the treatment of lower urinary tract symptoms.

Pharmaceuticals Incorporated. Flomax (tamsulosin) prescribing information.

Pharmacokinetics and Pharmacodynamics of Tamsulosin in its Modified-Release and Oral Controlled Absorption System Formulations.

quantification, and localization of mRNA for three distinct alpha-1 adrenergic receptor subtypes in human prostate.J Urol

Tamsulosin � turn a round

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