PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of cuajLink to Publisher's site
 
Can Urol Assoc J. 2010 August; 4(4): 269–275.
PMCID: PMC2910774

Language: English | French

A practical guide to diagnosis, management and treatment of testosterone deficiency for Canadian physicians

Alvaro Morales, MD, FRCSC, FACS, DABU,* Anthony J. Bella, MD, FRCSC, Samuel Chun, MD, FRCSC, Jay Lee, MD, FRCSC,§ Peter Assimakopoulos, MD, FRCPC,Δ Richard Bebb, MD, ABIM (IM/ENDO), FRCPC (IM/ENDO), Irv Gottesman, MD, FRCPC, FACP, FACE,** Pierre Alarie, MD,†† Hélène Dugré, MD,‡‡ and Stacy Elliott, MD§§

Abstract

The percentage of men receiving appropriate management for testosterone deficiency syndrome (TDS) is small in comparison to prevalence estimates. This is despite linkages to cardiovascular disease, osteoporosis, diabetes, sexual function, sarcopenia, emotional well-being and the metabolic syndrome. Furthermore, the availability of guidelines has not significantly enhanced the care of TDS patients. A multidisciplinary group of medical experts sought to improve the management of testosterone-deficient patients by Canadian physicians. This report describes their conclusions and defines an algorithm for appropriate TDS management.

Résumé

Le pourcentage d’hommes recevant une prise en charge appropriée pour un syndrome de carence en testostérone est faible en comparaison avec les taux de prévalence évalués, et ce, malgré le lien entre ce syndrome et les maladies cardiovasculaires, l’ostéoporose, le diabète, la fonction sexuelle, la sarcopénie, le bien-être émotionnel et le syndrome métabolique. Par ailleurs, la publication de guides de pratique n’a pas amélioré de façon significative les soins offerts aux patients atteints du syndrome de carence en testostérone. Une équipe multidisciplinaire de médecins a tenté d’améliorer la prise en charge des patients atteints de ce syndrome par les médecins canadiens. Le présent rapport décrit leurs conclusions et propose un algorithme de prise en charge.

Introduction

Testosterone deficiency syndrome (TDS), formerly termed andropause, is characterized by a deficiency in serum testosterone (T) levels with or without changes in receptor sensitivity to androgens. This syndrome is also variably referred to as hypogonadism or late-onset hypogonadism (LOH). There are various clinical manifestations of TDS (Fig. 1).

Fig. 1
Clinical manifestations of testerone deficiency.

Reduced T levels have been associated with the intake of certain medications (e.g., ketoconazole, spironolactone, estrogens, methadone) and the presence of comorbid conditions, such as diabetes, hypothyroidism, chronic obstructive pulmonary disease (COPD), obesity, hemochromatosis and the metabolic syndrome (MetS).1,2 Testosterone levels also decline with age, and a subset of men over age 40 may display clinically relevant TDS.3,4 It is expected that over the next 40 years life expectancy in North America will increase by 4.8 years.5 Therefore, it is likely that the prevalence of TDS will rise during this period from the current Canadian crude prevalence rates that show 25% of men aged 40 to 62 years as biochemically testosterone deficient.6

Recent consensus recommendations and guidelines for TDS diagnosis and management are available;1,4 yet, less than 10% of affected individuals receive T therapy,7 suggesting underutilization of these guidelines. Barriers to proper diagnosis and management may include: (1) a lack of physician awareness on associated diseases (such as MetS, diabetes and cardiovascular disease) and the ability of testosterone replacement therapy (TRT) to reduce disease symptoms,811 (2) unfounded concerns about prostate health4,12 and (3) insufficient dissemination of the guidelines in Canada. To reduce these barriers a multidisciplinary panel convened with the goal of improving TDS knowledge transfer to Canadian physicians. (A panel of urologists, endocrinologists and family physicians met in Toronto, February 5 to 6, 2010. The relevant literature was reviewed and consensus recommendations were formulated.) This report summarizes the essential findings of the panel into key recommendations and a concise, practical TDS management algorithm (Fig. 2).

Fig. 2
A practical management algorithm for TDS.

Detection and selective screening for TDS

Effective management of TDS begins with an initial screening of high-risk men. A proportion of males with certain clinical disorders exhibit a high prevalence of low T levels (Table 1).1 The incidence of diabetes and T deficiency are directly correlated: 33% of men with diabetes have hypogonadism,13 and men with higher levels of T (15.6–21.0 nmol/L) have a 42% lower risk of type II diabetes.14 In particular, the Canadian Diabetes Association guidelines state that all men with diabetes should be screened for erectile dysfunction (ED), as 34% to 45% of men with diabetes have ED.15 The Endocrine Society guidelines also suggest that all men with Type II diabetes be screened for testosterone deficiency.1

Table 1
Clinical disorders or conditions associated with a high prevalence of low T levels

Alternatively, patients may report symptoms consistent with TDS, such as fatigue, insomnia, decreased libido, reduced vitality, mood changes and ED.1,4 A thorough history and physical examination may reveal other clinical manifestations that are often consistent with the degree of T deficiency (Fig. 1).1,4,16,17 These manifestations may be present alone or in combination.

Screening questionnaires have been developed to record and evaluate patient history and symptoms. The Androgen Deficiency in Aging Males (ADAM) instrument (Appendix 1) is most widely accepted. This questionnaire has been evaluated for its correlation with serum levels of T;6,18 although it shows high sensitivity (88%6 and 81%18), its specificity is marginal (66%6 and 21.6%18). Good sensitivity indicates that the ADAM questionnaire correctly identifies those individuals with biochemically low T, but a lack of specificity may lead to inappropriate classification of men as hypogonadal or normal.

Diagnosis of TDS

Patients with symptoms suggestive of TDS require biochemical evaluation of serum T. Circadian rhythm influences T levels: higher T values are obtained in the morning.19 As a result, blood samples should be obtained between 7 and 11 am.4

Serum T circulates in a free or bound state. Most T is bound to either sex hormone-binding globulin (SHBG) (60%) or albumin (38%). Testosterone is tightly bound to SHBG, but weakly bound to albumin. Consequently, both albumin-bound T and free T (FT) are accessible to target tissues and constitute the bioavailable (BT) fraction that carries out the actions of T. Sex hormone-binding globulin-bound T is not biologically active. Generally, TDS manifestations correlate with the degree of T deficiency.16

The panel recognized measured BT as the gold standard for biochemistry. Additionally, the ammonium sulphate precipitation technique correlates well with symptoms of TDS.20 If measured BT is unavailable or unaffordable, calculated free T (cFT), calculated bioavailable T (cBT) or total T (TT) are acceptable alternatives.21 A free calculator for cFT and cBT is available online at the website for the International Society for the Study of the Aging Male (www.issam.ch). The calculated methods closely correlate with FT values obtained through laboratory assays, yet there are shortcomings: (1) SHBG levels vary up to twofold with different assays, and (2) aging and illness alter the binding characteristics of SHBG or serum.

The panel has not defined cut-off values for normal T levels because of difficulties with equipment standardization and interlaboratory variability. Instead, it is recommended that physicians consistently use the same local laboratories and gain familiarity with the accuracy, precision and definition of normal values for the assays offered in their community.

Some men may show marked intraindividual weekly variability in T values,22 and up to 50% of young healthy men have temporary T levels below the normal range in a 24-hour period.23 Therefore, abnormal (low or borderline) T levels require confirmation with a repeat T determination plus SHBG and a measure of serum luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin. In young men, chronic elevation of LH and FSH, combined with low levels of T, is clearly diagnostic of primary (testicular) hypogonadism. These diagnostic criteria are not as clearly defined in older men. Patients with secondary hypogonadism (hypothalamic-pituitary) have low T and normal LH and FSH levels. A combination of primary and secondary causes of TDS is often at play.

For definitive diagnosis of hypogonadism, physicians should rule out other clinical conditions that may masquerade as TDS. For example, some symptoms of TDS are consistent with depression or hypothyroidism, the latter diagnosed through detection of elevated serum thyroid-stimulating hormone (TSH). Measures of prolactin and ferritin can exclude hyperprolactinemia and hemochromatosis, respectively. Physicians should consider referral in patients with elevated prolactin levels. To exclude the possibility of pituitary/hypothalamic lesions, magnetic resonance imaging (MRI) should be performed in patients with very low levels of T and persistent hyperprolactinemia,24,25 or in patients with prolactin levels greater than 2 times the upper normal limit.26

Treatment of TDS

Testosterone formulations

Testosterone replacement therapy is suggested in patients with TDS. The goal of treatment is symptom improvement and achievement of physiological T levels. A number of safe and effective T products have been developed for treatment with varying delivery mechanisms. The currently available approved formulations in Canada include injectable, oral and transdermal agents (Table 2).

Table 2
Common testosterone formulations available in Canada

Intramuscular injection products include testosterone cypionate (Depo-Testosterone27) and testosterone enanthate (Delatestryl28). These preparations are relatively inexpensive, effective and long-acting.29 Both products induce supra-physiologic serum T levels in the first few days of the cycle. These formulations also have a waning effect that can result in the reappearance of T deficiency manifestations towards the end of the treatment cycle (2 to 3 weeks after injection).

Testosterone undecanoate is formulated in Canada in the convenience of an oral preparation (Andriol30 or pms-Testosterone31). These products may induce supraphysiologic levels of dihydrotestosterone.32 To permit absorption, testosterone undecanoate must be taken with a high-fat meal. Absorption issues may lead to poor responses.

Two transdermal T products are also available in Canada. Testosterone gels (AndroGel33 and Testim34) are transdermal gels applied daily to the skin that achieve consistent T levels.3537 Side effects of the gels are minimal, mainly minor skin reactions. Patients may prevent secondary exposure through contact transfer by washing their hands after applying the gel, covering the application sites with clothing, and washing the site thoroughly prior to anticipated skin-to-skin contact with another individual.

The transdermal patch (Androderm38) is an alternative to the gels with similar effectiveness; however, visibility and significant skin reactions are drawbacks of this product.39,40

The choice of T formulation should be based on physician and patient discussions with regard to the ASTEP acronym: availability, safety, tolerability, efficacy and preference. Physicians should be aware of the suggested follow-up periods and adverse events of each T product.

Benefits of TRT

Testosterone treatment has been shown to improve many of the symptoms of TDS and enhance overall health and potentially survival.41 Clinical studies indicate that T therapy enhances strength,42 sexual desire,43,44 energy,45 emotional well-being and cognition.4547 Bone mineral density (BMD) is increased by T therapy in men with low T levels.48,49 Testosterone replacement therapy reduces body fat,50 enhances glycemic control in diabetic patients and may improve some components of MetS.8 Men with profound hypogonadism show significant improvement in ED when on TRT.35,51 Evidence is emerging that T may also improve cardiovascular health in hypogonadal men.911

Contraindications to TRT

Patients should be evaluated for other medical conditions that may lead to adverse events upon treatment. Testosterone therapy is absolutely contraindicated in men with breast or prostate carcinomas.1,4 Prior to initiation of T therapy, it is recommended that physicians measure the prostate-specific antigen (PSA) level and perform a digital rectal examination (DRE). Patients with abnormal PSA or DRE findings should be referred to a urologist for further evaluation.

Testosterone therapy may also worsen other medical conditions, including erythrocytosis, untreated obstruc tive sleep apnea and severe congestive heart failure.50,52 Erythrocytosis can be revealed through a complete blood count (CBC). Testosterone replacement therapy is not suggested for men wishing biological fatherhood as T may reduce sperm production. Treatment with T in men with any of these medical conditions should not be initiated until these issues have been addressed

Alternative treatments to TRT

Occasionally, some testosterone deficiency manifestations can be managed with reversal of an underlying cause, drug therapy or lifestyle modifications (Table 3). Treatment of sleep apnea,53 weight reduction54 and discontinuation of opioid medication55 may improve manifestations of T deficiency. Yet, the poor adherence to many of these regimens (e.g., diet and exercise) makes T therapy a logical option.

Table 3
Common alternative/complementary approaches to testosterone replacement therapy for the management of testosterone deficiency syndrome manifestations

Monitoring

Patients should be examined regularly for symptom response and changes in blood parameters. Monitoring should occur every 3 to 6 months in the first year and at yearly intervals thereafter if the patient is stable. Some improvements in the clinical manifestations of TDS may be observed in the first 3 to 6 months of TRT, while other symptoms may take longer to resolve (Fig. 3).4 Non-response may be indicative of compliance issues, malabsorption, insufficient dose, an unsatisfactory formulation or symptoms unrelated to TDS. Long-term lack of response may require referral to a specialist. Combination therapy with T and phosphodiesterase-5 inhibitors (PDE5i) may prove useful in ED patients who fail initial treatment with T alone. Likewise, ED patients who fail initial therapy with PDE5i alone should be screened for T deficiency and may benefit from the addition of T to their treatment regimen.

Fig. 3
Anticipated symptom improvement of TRT and approximate timeliness of visualization.

At each appointment, the patient should undergo an assessment of clinical response and adverse events. Levels of serum T and hemoglobin should be determined along with a hematocrit. Prostate health should be assessed by PSA and DRE. The patient should be referred if DRE findings are suspicious or PSA levels increase. An elevated hematocrit is characteristic of erythrocytosis, which can develop from T treatment (particularly the depot formulations). These patients should receive dose adjustments or a change of delivery form to maintain hematological values within a normal range.1,35

Conclusions

This paper highlights several key features of TDS:

  • The prevalence of TDS is significant in men over 40 years of age, but only a small proportion is treated adequately.
  • Testosterone deficiency syndrome is a significant health issue because of the association of low T levels with diabetes, cardiovascular disease, osteoporosis and a decrease in life quality and expectancy.
  • Diagnosis of TDS requires the presence of clinical manifestations and laboratory confirmation of abnormal T levels.
  • Confirmed TDS may be managed with lifestyle modifications and appropriate use of an injectable, oral or transdermal T preparation.
  • Symptom response and safety of TRT should be monitored regularly with a physical examination, comprehensive serum analysis and DRE.

Acknowledgments

The authors acknowledge the administrative and editorial assistance of Core Health Services Inc. (Toronto, ON) for the development of this publication. Medical writing and editing was performed by Karla Badger-Brown, PhD. Commercial support for this publication has been provided by Abbott (Solvay Pharmaceuticals is now Abbott).

Appendix A. 

ADAM Questionnaire*

A positive answer represents Yes to questions 1 or 7 or any 3 other questions
YESNO
1. Do you have a decrease in libido (sex drive)?
2. Do you have a lack of energy?
3. Do you have a decrease in strength and/or endurance?
4. Have you lost height?
5. Have you noticed a decreased enjoyment of life?
6. Are you sad and/or grumpy?
7. Are your erections less strong?
8. Have you noticed a recent deterioration in your ability to play sports?
9. Are you falling asleep after dinner?
10. Has there been a recent deterioration in your work performance?
*Morley et al. (6).

Footnotes

Competing interests: Dr. Alvaro Morales: Clinical trials sponsored by Endo (US) and Paladin Labs Inc.; Received honoraria from Bioniche Life Sciences and Solvay Pharmaceuticals Inc. Dr. Anthony Bella: Advisory Board Member for American Medical Systems, Eli Lilly Canada Inc., and Pfizer Canada Inc.; Speaker’s Bureau for American Medical Systems, Eli Lilly Canada Inc., and Pfizer Canada Inc.; Meeting support for Solvay Pharmaceuticals Inc.; Basic Science Research support - Canadian Foundation for Innovation, Canadian Male Sexual Health Council, Northeastern Section of the American Urological Association, ACORDA Therapeutics. Endowed Chair in Men’s Health Research - The Ottawa Hospital Foundation. Dr. Samuel Chun: Advisory Board Member for GlaxoSmithKline Inc., and Solvay Pharmaceuticals Inc.; Speaker’s Bureau for Bayer Inc., Eli Lilly Canada Inc., Johnson & Johnson Inc., Paladin Labs Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc. Dr. Jay Lee: Advisory Board Member for Bayer Inc., Eli Lilly Canada Inc., GlaxoSmithKline Inc., Paladin Labs Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc.; Speaker’s Bureau for Bayer Inc., Boehringer Ingelheim Canada Ltd., Eli Lilly Canada Inc., GlaxoSmithKline Inc., Merck Frosst Canada Ltd., Paladin Labs Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc.; Research for Bayer Inc., Eli Lilly Canada Inc., GlaxoSmithKline Inc. and Pfizer Canada Inc. Dr. Peter Assimakopoulos: Advisory Board Member for Auxilium Pharmaceuticals Inc.; Advisory Board Member and/or Speaker’s Bureau for Amgen Canada, AstraZeneca Canada Inc., Boehringer Ingelheim Canada Ltd., Bristol-Myers Squibb Canada, Eli Lilly Canada Inc., Merck Frosst Canada Ltd., Novartis Canada, and sanofi-aventis Canada in the last two years. Dr. Richard Bebb: Clinical trial funding, Honoraria for CME events and/or involved with Advisory Board meetings for AstraZeneca Canada Inc., Bayer Inc., Eli Lilly Canada Inc., GlaxoSmithKline Inc., Merck Frosst Canada Ltd., Novo Nordisk Canada Inc., Organon Canada, Paladin Labs Inc., Pfizer Canada Inc., sanofi-aventis Canada, Schering-Plough Canada, and Solvay Pharmaceuticals Inc. Dr. Irv Gottesman – Clinical trial funding, Honoraria for CME events and/or involved with Advisory Board meetings for AstraZeneca Canada Inc., Bayer Inc., Biovail Pharmaceuticals Canada, Bristol-Myers Squibb Canada, Boehringer Ingelheim Canada Ltd., Eli Lilly Canada Inc., GlaxoSmithKline Inc., Janssen-Ortho, Merck Frosst Canada Ltd., Novartis Canada, Novo Nordisk Canada Inc., Paladin Labs Inc., Pfizer Canada Inc., sanofi-aventis Canada, Schering-Plough Canada, and Solvay Pharmaceuticals Inc. Dr. Pierre Alarie – Advisory Board Member for Eli Lilly Canada Inc. and Solvay Pharmaceuticals Inc.; Clinical Trials / Research for Eli Lilly Canada Inc., Johnson & Johnson Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc.; Speaker’s Bureau for Bayer Inc., Eli Lilly Canada Inc., Pfizer Canada Inc., Schering-Plough Canada, and Solvay Pharmaceuticals Inc. Dr. Hélène Dugré – Advisory Board Member for Eli Lilly Canada Inc.; Clinical Trials / Research for Pfizer Canada Inc.; CHE content development for Pfizer Canada Inc.; Speaker’s Bureau for Pfizer Canada Inc., Eli Lilly Canada Inc., Schering-Plough Canada, and Solvay Pharmaceuticals Inc. Dr. Stacy Elliott – Advisory Board Member for Bayer Inc., Johnson & Johnson Inc., Eli Lilly Canada Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc.; CHE content development for Eli Lilly Canada Inc.; Speaker’s Bureau for Bayer Inc., Johnson & Johnson Inc., Eli Lilly Canada Inc., Pfizer Canada Inc., and Solvay Pharmaceuticals Inc.

This paper has been peer-reviewed.

References

1. Bhasin S, Cunningham G, Hayes F, et al. Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2010;95:2536–59. [PubMed]
2. Dandona P, Dhindsa S, Chaudhuri A, et al. Hypogonadotrophic hypogonadism in type 2 diabetes, obesity and the metabolic syndrome. Curr Mol Med. 2008;8:816–28. [PubMed]
3. Liu PY, Beilin J, Meier C, et al. Age-related changes in serum testosterone and sex hormone binding globulin in Australian men: longitudinal analyses of two geographically separate regional cohorts. J Clin Endocrinol Metab. 2007;92:3599–603. [PubMed]
4. Wang C, Nieschlag E, Swerdloff R, et al. Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations. Eur J Endocrinol. 2008;159:507–14. [PMC free article] [PubMed]
5. United Nations DoEaS, Affairs Population D World Population Prospects: The 2006 Revision, Highlights, Working Paper No. ESA/P/WP.202; 2007.
6. Morley JE, Charlton E, Patrick P, et al. Validation of a screening questionnaire for androgen deficiency in aging males. Metabolism. 2000;49:1239–42. [PubMed]
7. Carruthers M. Time for international action on treating testosterone deficiency syndrome. Aging Male. 2009;12:21–8. [PMC free article] [PubMed]
8. Heufelder AE, Saad F, Bunck MC, et al. Fifty-two-week treatment with diet and exercise plus transdermal testosterone reverses the metabolic syndrome and improves glycemic control in men with newly diagnosed type 2 diabetes and subnormal plasma testosterone. J Androl. 2009;30:726–33. [PubMed]
9. Malkin CJ, Pugh PJ, Morris PD, et al. Testosterone replacement in hypogonadal men with angina improves ischaemic threshold and quality of life. Heart. 2004;90:871–6. [PMC free article] [PubMed]
10. Pugh PJ, Jones TH, Channer KS. Acute haemodynamic effects of testosterone in men with chronic heart failure. Eur Heart J. 2003;24:909–15. [PubMed]
11. Malkin CJ, Pugh PJ, West JN, et al. Testosterone therapy in men with moderate severity heart failure: a double-blind randomized placebo controlled trial. Eur Heart J. 2006;27:57–64. [PubMed]
12. Gooren LJ, Behre HM, Saad F, et al. Diagnosing and treating testosterone deficiency in different parts of the world. Results from global market research. Aging Male. 2007;10:173–81. [PubMed]
13. Dhindsa S, Prabhakar S, Sethi M, et al. Frequent occurrence of hypogonadotropic hypogonadism in type 2 diabetes. J Clin Endocrinol Metab. 2004;89:5462–8. [PubMed]
14. Ding EL, Song Y, Malik VS, et al. Sex differences of endogenous sex hormones and risk of type 2 diabetes: a systematic review and meta-analysis. JAMA. 2006;295:1288–99. [PubMed]
15. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee Canadian Diabetes Association 2008 clinical practice guidelines for the prevention and management of diabetes in Canada. Can J Diabetes. 2008;32(Suppl1):S1–S201.
16. Zitzmann M, Faber S, Nieschlag E. Association of specific symptoms and metabolic risks with serum testosterone in older men. J Clin Endocrinol Metab. 2006;91:4335–43. [PubMed]
17. Corona G, Jannini EA, Mannucci E, et al. Different testosterone levels are associated with ejaculatory dysfunction. J Sex Med. 2008;5:1991–8. [PubMed]
18. Tancredi A, Reginster JY, Schleich F, et al. Interest of the androgen deficiency in aging males (ADAM) questionnaire for the identification of hypogonadism in elderly community-dwelling male volunteers. Eur J Endocrinol. 2004;151:355–60. [PubMed]
19. Diver MJ, Imtiaz KE, Ahmad AM, et al. Diurnal rhythms of serum total, free and bioavailable testosterone and of SHBG in middle-aged men compared with those in young men. Clin Endocrinol (Oxf) 2003;58:710–7. [PubMed]
20. Rosner W, Auchus RJ, Azziz R, et al. Position statement: Utility, limitations, and pitfalls in measuring testosterone: an Endocrine Society position statement. J Clin Endocrinol Metab. 2007;92:405–13. [PubMed]
21. Vermeulen A, Verdonck L, Kaufman JM. A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab. 1999;84:3666–72. [PubMed]
22. Collier CP, Morales A, Clark A, et al. The significance of biological variation in the diagnosis of testosterone deficiency, and considerations of the relevance of total, free and bioavailable testosterone determinations. J Urol. 2010;183:2294–9. [PubMed]
23. Spratt DI, O’Dea LS, Schoenfeld D, et al. Neuroendocrine-gonadal axis in men: frequent sampling of LH, FSH, and testosterone. Am J Physiol. 1988;254:E658–66. [PubMed]
24. Citron JT, Ettinger B, Rubinoff H, et al. Prevalence of hypothalamic-pituitary imaging abnormalities in impotent men with secondary hypogonadism. J Urol. 1996;155:529–33. [PubMed]
25. Bunch TJ, Abraham D, Wang S, et al. Pituitary radiographic abnormalities and clinical correlates of hypogonadism in elderly males presenting with erectile dysfunction. Aging Male. 2002;5:38–46. [PubMed]
26. Rhoden EL, Estrada C, Levine L, et al. The value of pituitary magnetic resonance imaging in men with hypogonadism. J Urol. 2003;170:795–8. [PubMed]
27. Prescribing Information: Depo-Testosterone (testosterone cypionate injection USP) 100 mg/mL Sterile solution. Kirkland, Quebec: Phizer Canada Inc; 2007.
28. Prescribing Information: Delatestryl, testosterone enanthate, Solution for Injection, 200 mg/mL. Mississauga, Ontario: Theramed Corporation; 2007.
29. Amory JK, Watts NB, Easley KA, et al. Exogenous testosterone or testosterone with finasteride increases bone mineral density in older men with low serum testosterone. J Clin Endocrinol Metab. 2004;89:503–10. [PubMed]
30. Product Monograph: Andriol (testosterone undecanoate capsules), 40 mg. Kirkland, Quebec: Schering-Plough Canada Inc.; 2008.
31. Product Monograph: pms-Testosterone (testosterone undecanoate) 40 mg Capsules. Montreal, Quebec: Pharmascience Inc; 2009.
32. Gooren LJ. A ten-year safety study of the oral androgen testosterone undecanoate. J Androl. 1994;15:212–5. [PubMed]
33. Product Monograph: AndroGel, Testosterone gel, 1%. Markham, Ontario: Solvay Pharma Inc; 2010.
34. Product Monograph: Testim 1% (testosterone gel) Malvern, Pennsylvania: Auxilium Pharmaceuticals Inc; 2009.
35. Wang C, Cunningham G, Dobs A, et al. Long-term testosterone gel (AndroGel) treatment maintains beneficial effects on sexual function and mood, lean and fat mass, and bone mineral density in hypogonadal men. J Clin Endocrinol Metab. 2004;89:2085–98. [PubMed]
36. Swerdloff RS, Wang C, Cunningham G, et al. Long-term pharmacokinetics of transdermal testosterone gel in hypogonadal men. J Clin Endocrinol Metab. 2000;85:4500–10. [PubMed]
37. Dean JD, Carnegie C, Rodzvilla J, et al. Long-term effects of testim(r) 1% testosterone gel in hypogonadal men. Rev Urol. 2005;7:87–94. [PubMed]
38. Product Monograph: Androderm Testosterone, Transdermal Delivery System, 122 mg and 243 mg. Montreal, Quebec: Paladin Labs Inc; 2007.
39. Wang C, Swerdloff RS, Iranmanesh A, et al. Transdermal testosterone gel improves sexual function, mood, muscle strength, and body composition parameters in hypogonadal men. J Clin Endocrinol Metab. 2000;85:2839–53. [PubMed]
40. Jordan WP, Jr, Atkinson LE, Lai C. Comparison of the skin irritation potential of two testosterone transdermal systems: an investigational system and a marketed product. Clin Ther. 1998;20:80–7. [PubMed]
41. Laughlin GA, Barrett-Connor E, Bergstrom J. Low serum testosterone and mortality in older men. J Clin Endocrinol Metab. 2008;93:68–75. [PubMed]
42. Ottenbacher KJ, Ottenbacher ME, Ottenbacher AJ, et al. Androgen treatment and muscle strength in elderly men: A meta-analysis. J Am Geriatr Soc. 2006;54:1666–73. [PMC free article] [PubMed]
43. Steidle C, Schwartz S, Jacoby K, et al. AA2500 testosterone gel normalizes androgen levels in aging males with improvements in body composition and sexual function. J Clin Endocrinol Metab. 2003;88:2673–81. [PubMed]
44. Clopper RR, Voorhess ML, MacGillivray MH, et al. Psychosexual behavior in hypopituitary men: a controlled comparison of gonadotropin and testosterone replacement. Psychoneuroendocrinology. 1993;18:149–61. [PubMed]
45. Rhoden EL, Morgentaler A. Symptomatic response rates to testosterone therapy and the likelihood of completing 12 months of therapy in clinical practice. J Sex Med. 2010;7:277–83. [PubMed]
46. Zitzmann M. Testosterone and the brain. Aging Male. 2006;9:195–9. [PubMed]
47. Pope HG, Jr, Cohane GH, Kanayama G, et al. Testosterone gel supplementation for men with refractory depression: a randomized, placebo-controlled trial. Am J Psychiatry. 2003;160:105–11. [PubMed]
48. Snyder PJ, Peachey H, Hannoush P, et al. Effect of testosterone treatment on bone mineral density in men over 65 years of age. J Clin Endocrinol Metab. 1999;84:1966–72. [PubMed]
49. Khosla S. Update in male osteoporosis. J Clin Endocrinol Metab. 2010;95:3–10. [PubMed]
50. Bhasin S, Buckwalter JG. Testosterone supplementation in older men: a rational idea whose time has not yet come. J Androl. 2001;22:718–31. [PubMed]
51. Jockenhovel F, Minnemann T, Schubert M, et al. Comparison of long-acting testosterone undecanoate formulation versus testosterone enanthate on sexual function and mood in hypogonadal men. Eur J Endocrinol. 2009;160:815–9. [PubMed]
52. Calof OM, Singh AB, Lee ML, et al. Adverse events associated with testosterone replacement in middle-aged and older men: a meta-analysis of randomized, placebo-controlled trials. J Gerontol A Biol Sci Med Sci. 2005;60:1451–7. [PubMed]
53. Luboshitzky R, Aviv A, Hefetz A, et al. Decreased pituitary-gonadal secretion in men with obstructive sleep apnea. J Clin Endocrinol Metab. 2002;87:3394–8. [PubMed]
54. Mohr BA, Bhasin S, Link CL, et al. The effect of changes in adiposity on testosterone levels in older men: longitudinal results from the Massachusetts Male Aging Study. Eur J Endocrinol. 2006;155:443–52. [PubMed]
55. Katz N, Mazer NA. The impact of opioids on the endocrine system. Clin J Pain. 2009;25:170–5. [PubMed]

Articles from Canadian Urological Association Journal are provided here courtesy of Canadian Urological Association