Indian Journal of Urology
ORIGINAL ARTICLE
Year
: 2001  |  Volume : 17  |  Issue : 2  |  Page : 132--140

Prospective double-blind randomized controlled trial of terazosin, finasteride and allylestrenol in the management of benign prostatic hyperplasia


Madhu S Agrawal, Monish Aron 
 Departments of Urology, S. N. Medical College, Agra, and All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Madhu S Agrawal
4/18-C, Bagh Farzana, Civil Lines, Agra- 282002
India

Abstract

Medical management is rapidly becoming a very im­portant part of the armamentarium of the urologist in­volved in the treatment of benign prostatic hyperplasia. The commonest options for medical management include alpha-blockers, 5-alpha reductase inhibitors, and pro­gestational anti-androgens. We present a double-blind randomized controlled trial evaluating the safety and efficacy of terazosin, finasteride and allylestrenol, the prototype drugs in each of these respective categories. A total of 140 patients who satisfied the inclusion and exclusion criteria were inducted into the trial after an informed consent. They were randomized into 4 groups, which received placebo, terazosin, finasteride and allylestrenol respectively for 6 months. Since 29 patients did not complete 6 months of therapy, there were 111 evaluable patients at the end of the study. We found that these 3 drugs produce comparable improvement in symp­tom score (-40%), flow rates (-60%) and PVR (-50%) which is significantly better than that in the placebo group. Both allylestrenol and finasteride bring about a comparable reduction in prostate volume (-23%), which is statistically significant as compared to the placebo and terazosin groups. Terazosin in doses of I and 2 mg/ day was, found to be effiective and well-tolerated in the vast majority of our cases. No adverse effects were seen in the placebo and finasteride groups, while 9.6% in the terazosin group had postural hypotension and 10.7% in the allylestrenol group had some loss of libido, prob­lems which were reversible upon cessation of therapy.



How to cite this article:
Agrawal MS, Aron M. Prospective double-blind randomized controlled trial of terazosin, finasteride and allylestrenol in the management of benign prostatic hyperplasia.Indian J Urol 2001;17:132-140


How to cite this URL:
Agrawal MS, Aron M. Prospective double-blind randomized controlled trial of terazosin, finasteride and allylestrenol in the management of benign prostatic hyperplasia. Indian J Urol [serial online] 2001 [cited 2019 Aug 25 ];17:132-140
Available from: http://www.indianjurol.com/text.asp?2001/17/2/132/21043


Full Text

 Introduction



Benign prostatic hyperplasia (BPH) is found in about 50% of the male population in their fifth decade and shows a tendency to increase to 80% in men over 80 years of age. [1] Based upon data from the normative aging study, the cumulative incidence of BPH, judged by physical find­ings or symptoms for a 40-year old man surviving to age 80, is 78% and that of a prostatectomy is 29%. [2] Transurethral resection of the prostate (TURP) is the gold standard in the management of these cases but its complications, hospital stay, anesthesia and cost necessitate a constant search for an alternative treatment. A recent survey of the U.S. Medicare database revealed that the absolute number of prostatecto­mies decreased over 30% despite the progressively increas­ing number of males enrolled in the Medicare program. [3] This decrease in the number of prostatectomies coincides with the evolution and acceptance of medical therapy. In patients in whom there is no absolute indication for prostatectomy or those who are unfit or waiting for surgery, several drugs have been tried, the most common of which are terazosin (an alpha blocker), finasteride (a 5-alpha reductase inhibi­tor), and allylestrenol (a progestational agent). Although several studies on terazosin and finasteride are available from Europe and the United States, the literature on allylestrenol appears principally from Japan. However, very little data is available from Indian subcontinent on the comparative safety and efficacy of these drugs. We present the results of a pro­spective double-blind randomized trial conducted to deter­mine the efficacy and safety of the 3 most commonly used agents in the medical management of BPH.

 Patients and Methods



Between January and December 1997, a total of 140 pa­tients were enrolled into the study after an informed con­sent. The inclusion criteria were:

a) age 45-80 years

b) symptoms of prostatism (Boyarsky symptom score >8)

c) maximum flow rate (MFR) exclusion criteria were:

a) prostate cancer

b) complicated BPH (acute or chronic retention, recur­rent urinary infection, hematuria, upper tract changes and bladder calculi)

c) patients with other causes for poor flow (stricture urethra, neurogenic bladder)

d) significant co-morbid illnesses

e) history of intake of drugs that affect voiding

f) prior surgery on the prostate or bladder neck

These patients were randomized, in a prospective manner, into 4 groups, of 35 patients each using computer generated random numbers. Patients in group I received a placebo tablet once daily, group 11 received terazosin 1-10 mg daily, group Ill received finasteride 5 mg daily and group IV received allylestrenol 25 mg twice daily. All patients underwent a base­line evaluation prior to starting the drug, which included a detailed history and examination, including blood pressure measurement and digital rectal examination (DRE), electro­cardiogram, hemogram, blood chemistry, urinalysis, urine cul­ture and serum PSA. The parameters for comparison between each drug were recorded at this evaluation and at subsequent visits. These were:

1. Symptom score (Boyarsky et al) [4]

2. Prostate volume (as determined by transrectal ultra­sound) in ml

3. Maximum flow rate (MFR) in mi/s

4. Post-void residual urine (PVR) in ml (as determined by abdominal ultrasound)

The dosage remained constant in all groups except group II where terazosin was used in a dose escalation schedule, beginning with 1 mg daily at bedtime and increasing to 2mg, 5 mg, and 10 mg at weekly intervals, up to the maximum tolerated dose. Only 7 patients in this study went up to or beyond 5 mg/day, with only 2 patients receiving 10 mg/day on a regular basis. All patients were called for follow-up, fortnightly for the first 2 months and then monthly for an­other 4 months. The same parameters were recorded again at the visit at 1 month, 3 months and 6 months. Any adverse effects including the effects on blood pressure and libido were noted. In order to eliminate observer bias, the study was con­ducted in completely double-blind fashion so that the person recording the parameters was not aware of the drug the pa­tient was taking. The data in terms of the observed param­eters was statistically analyzed using the student's t-test. A p value [5] Prostatic smooth muscle accounts for 51% of the total stromal volume in BPH. [6] The prostatic smooth muscle contains alpha, adreno­ceptors that mediate its contraction. The mechanism of bladder outlet obstruction in men with BPH has been attributed to static and dynamic factors, [7] the dynamic com­ponent being due to the tone of the prostatic smooth mus­cle and the static component due to the anatomic enlargement encroaching upon the bladder outlet. This concept forms the basis for the two main arms of pharma­cotherapy for BPH, namely, alpha, receptor blockade to control the dynamic component, and hormonal mani­pulafion for the static component.

The pathogenesis of BPH has been reviewed in detail by Walsh [8] and Wilson. [9] Development of the disease clearly requires a combination of testicular androgens and aging. Since the recognition that BPH is an androgen dependent process, numerous treatment strategies to inhibit androgen production or action in the prostate have been devised and tested. Indeed, both approaches, namely, alpha-blockade and androgen deprivation, appear to have value in the manage­ment of these patients. However, in evaluation of these agents, it must be recognized that a strong placebo effect is associated with the management of BPH, and that for any trial to be meaningful, it needs to be properly controlled.

The proposed mechanism for the efficacy of alpha 1 blockade in BPH is via relaxation of prostatic smooth mus­cle, which lowers outflow resistance without impairing detrusor contractility. Alpha-blockers used in the studies on the medical management of BPH can be sub-grouped according to their receptor selectivity and their elimination half-life. [10] The most extensively studied agent in this category is terazosin, which is a long-acting selective al­pha, blocker.

The primary advantage of the selective alpha 1 blockers is that the incidence and severity of side effects is consider­ably less than the nonselective alpha-blockers. The advan­tages of selective long-acting (once-a-day) alpha-blockers are related to compliance and tolerance. The most common adverse effects related to alpha, blockers include dizziness, light-headedness, asthenia and postural hypotension. The administration of long-acting, once-a-day formulations at bedtime reduce the incidence and severity of these adverse effects. [10] Terazosin is the most commonly used alpha, blocker in clinical practice and has been shown to be safe and effective over the long-term. [11]

Hormonal treatment of BPH can be given using several options, [12] including inhibiting pituitary LH secretion (GnRH agonists, like busrelin), androgen receptor inhibition (true anti-androgens like flutamide), inhibiting conversion of tes­tosterone to dihydrotestosterone (5α-reductase inhibitors like finasteride), and progestational antiandrogens (e.g. hydroxyprogesterone caproate, allylestrenol, and cyproter­one acetate).

Of these multiple options the most successful in clini­cal practice are the use of 5α -reductase inhibitors and progestogens. 5α -reductase inhibitors act by inhibiting conversion of testosterone to DHT, resulting in decreased levels of serum and prostatic DHT. Finasteride has been shown to reduce mean serum PSA levels by approximately 50%, [13] even though the effect on each individual patient is highly variable. The implications of the PSA-altering effect of finasteride, on the detection of prostate cancer, are as yet unresolved. [14] Finasteride has a very agreeable adverse event profile. Impotence and decreased ejaculate volume are the primary treatment-related side effects. However, in a recent multicenter study of 1229 patients with BPH, Lepor et al, [11] demonstrated no advantage of finasteride over placebo. A subset analysis of this study revealed that modest efficacy was seen only in patients with prostates larger than 50 cm 3 .

Interest in progestins for the management of BPH be­gan in 1965 with the report by Geller and associates that hydroxyprogesterone caproate results in prostatic regres­sion. [15] Progestational agents such as allylestrenol act not only by reducing the pituitary release of gonadotrophins, but also produce an androgen receptor blockade in the prostate. They also partly inhibit the enzyme 5α -reduct­ase responsible for the synthesis of DHT. The biggest draw­back with these agents is the loss of sexual function they produce by virtue of the reduction in pituitary gonado­trophin secretion. [16]

The present study was designed to determine the effi­cacy and adverse effect profile of these three agents in the medical management of BPH. We found that all 3 agents bring about subjective and objective improvement in pa­tients with BPH. These 3 drugs show comparable improve­ment in symptom score (-40%), flow rates (-60%) and PVR (-50%) which is significantly better than that in con­trols. It is interesting to note that nearly 15% subjective improvement was observed in the placebo group as well. Both allylestrenol and finasteride bring about a compara­ble reduction in prostate volume (-23%), although allylest­renol tends to cause a reversible loss of libido in about 10% of patients.

Contrary to reports from western literature, we found that 2 mg/day dose of terazosin is sufficient in the vast majority of our cases. Terazosin is well tolerated in doses up to 2 mg daily, although a 5 mg dose led to postural hypotension in several of our patients, and only 7 patients received doses of 5 mg or above in the present study. The first benefit from terazosin was noted as early as 2 weeks, while that with finasteride and allylestrenol appeared at 4 weeks, somewhat earlier than what has been described in the literature.

Of concern is the fact that as many as 20.7% of patients who were initially enrolled into the study did not com­plete 6-months' of therapy, and 10% did so because of inability or unwillingness for follow-up. This is an impor­tant consideration given the prolonged treatment time and regular follow-up essential for any patient being consid­ered for medical management. Overall, 9.2% of patients developed an indication for TURP during the study. This highlights the need for regular follow-up in these patients, without which they may suffer silent damage to the upper tracts and land up in renal failure.

 Conclusions



Terazosin, finasteride and allylestrenol have compara­ble effects on symptom score, PVR and MFR which are significantly better than placebo. The fastest response is seen with terazosin. Finasteride and allylestrenol produce similar reduction in prostate size and over a similar time frame. Finasteride has the most favorable adverse event profile. The incidence of postural hypotension and related adverse effects with terazosin is dose-dependent and can often be controlled by dose reduction. The adverse effects of allylestrenol are reversible with cessation of therapy, although the -10% incidence of loss of libido may be of concern to sexually active patients.

Although there is little doubt that these drugs are effec­tive treatment options for selected patients with BPH, cer­tain concerns remain. These include the need for prolonged (possibly life-long) therapy, high cost, need for long-term compliance and close follow-up, potential adverse effects and a lack of permanent effect on the primary pathology. Thus the role of medical management for BPH must be continually reassessed in terms of the community at large, keeping in mind the special socio-economic factors in the Indian context. At the present time, with the available drugs, it seems a safe and effective option for the well­informed and motivated patient, who is willing for close follow-up, and can afford prolonged therapy.

 Acknowledgements



We are thankful to M/S Cadila, Cipla, Intas, Infar, and Dr. Reddy's Laboratories for providing us with the vari­ous drugs used during this study.

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