(British Approved Name, rINN)

Drug Nomenclature

International Nonproprietary Names (INNs) in main languages (French, Latin, Russian, and Spanish):

Pharmacopoeias. In US.

The United States Pharmacopeia 31, 2008 (Testolactone). A white to off-white, practically odourless, crystalline powder. Soluble 1 in 4050 of water; soluble in alcohol and in chloroform; slightly soluble in benzyl alcohol; insoluble in ether and in petroleum spirit. Store in airtight containers.

Profile

Testolactone is a derivative of testosterone. It is reported to be an aromatase inhibitor that reduces peripheral oestrogen synthesis but has no significant androgenic activity. It has been used in the palliative treatment of advanced breast cancer in postmenopausal women. The usual oral dose is 250 mg four times daily. It should not be given to men with breast cancer. Peripheral neuropathies have occurred in patients given testolactone; gastrointestinal disturbances, pain or oedema of the extremities, hypertension, malaise, maculopapular erythema, and glossitis have also been reported.

Congenital adrenal hyperplasia. For mention of the use of testolactone with flutamide to block androgenic effects in congenital adrenal hyperplasia.

Precocious puberty. Encouraging results have been reported using testolactone in the treatment of 5 girls with precocious puberty due to the McCune-Albright syndrome. Testolactone is an aromatase inhibitor and blocks the synthesis of oestrogens from androgens. Long-term therapy (for up to 5 years) was associated with continued benefit in many patients; however, signs of puberty were not always completely suppressed, in some cases perhaps because of difficulties in maintaining the dosage regimen. Encouraging results were also obtained using testolactone with spironolactone in the treatment of familial precocious puberty in boys, although neither agent was successful when used alone. Again, signs of a reduced response to longer-term therapy have occurred; in this case control was restored by addition of a gonadorelin analogue Another study in 10 boys who were treated for at least 6 years with spironolactone and testolactone, with deslorelin added at the onset of secondary central precocious puberty, found normalisation in growth rate and bone maturation, and improvements in predicted adult height.

Preparations

The United States Pharmacopeia 31, 2008: Testolactone Tablets.

Single-ingredient Preparations

Belgium: Teslac; Chile: Teslac; Germany: Fludestrin; United States: Teslac

Mechanisms of Obstruction and Rationale for Pharmacotherapy

Current pharmacotherapy for Benign Prostatic Hyperplasia (BPH) is based on agents that relax the smooth muscles of prostatic urethra and stroma and those that deprive acinar cells of androgen.

Various agents have been tried in the treatment of BPH (Table). They may be broadly grouped into those affecting the dynamic component of urethral obstruction, namely the smooth muscle and prostatic stroma, and those affecting the glandular elements by androgen deprivation. The mechanism of action of many agents claimed to be useful in Benign Prostatic Hyperplasia is not clearly understood.

Caine has suggested that obstruction due to Benign Prostatic Hyperplasia occurs because of two factors: a dynamic component is thought to occur as a result of the contraction of smooth muscles of the prostate and prostatic urethra and is mediated mostly by adrenergic receptors; and a mechanical component of obstruction is related to the presence of a mass of hyperplastic acinar or stromal tissue that compresses and narrows the urethral lumen. There is some evidence that the presence and density of stromal content in BPH may relate to the severity of obstruction.

Current understanding of the biologic mechanisms of obstruction is limited and does not extend to two common clinical facts. The first is that the size of the prostate does not always correlate with the severity of symptoms or objective signs of obstruction. The second is the discrepancy between the histologic changes of BPH and the presence and severity of symptoms. From a physiologic standpoint, five conditions in patients with symptoms of “BPH” may exist singly or in combination. These are prostatic urethral obstruction, impaired detrusor contractility, detrusor instability, sensory urgency, and primary vesical neck obstruction. All these conditions likely result from varying combinations of prostatic enlargement and subtle neurologic dysfunction, all due to age-related central nervous system degeneration. Alternatively, a hyperplastic prostate during growth may disrupt normal sphincteric function. Thus, it is not surprising that prostatectomy fails to relieve symptoms of prostatism in about 20% of patients because the symptoms may be caused by poorly understood deficits in neurosensory pathways regulating micturition and sphincteric function.

Transurethral prostatectomy is the most common surgical procedure currently performed for the treatment of Benign Prostatic Hyperplasia. Outcome analyses have questioned the results of transurethral resection of the prostate (TURP). Patients undergoing TURP have been reported to be at greater risk from cardiovascular death than patients undergoing open prostatectomy. Recently these findings were disputed, and it was reported that transurethral resection for BPH does not increase long-term mortality and that comorbid illnesses and older age probably account for the apparent increase in long-term mortality after TURP. The morbidity of the procedure remains unchanged, however. In a review in 1962, the morbidity after transurethral resection of the prostate was reported to be 18% and the mortality 2.5%. More recently, the American Urological Association (AUA) cooperative study of 3,885 patients after the procedure revealed an overall complication rate of 18% and 0.2% mortality. Thus, the search for alternative therapies has been prompted by patients’ preferences for less invasive forms of treatment without prohibitive side effects. Apart from pharmacotherapy, other methods undergoing trials for the treatment of Benign Prostatic Hyperplasia include laser ablation, microwave hyperthermia, and prostatic stents. Ultimately, the role of surgical treatment and newer modalities must be based on relative effectiveness, cost, morbidity, effect on quality of life, expectations, and treatment preferences of patients.