- Email: [email protected]
Intracavernous Self-Injection with Phentolamine and Papaverine for the Treatment of Impotence
0022-534 7/87/1374-0678$02.00/0 Vol. 137, April
THE JOURNAL OF UROLOGY
Copyright© 1987 by The Williams & Wilkins Co.
Printed in U.S.A.
INTRACAVERNOUS SELF-INJECTION WITH PHENTOLAMINE AND PAPAVERINE FOR THE TREATMENT OF IMPOTENCE THOMAS C. GASSER, RICHARD M. ROACH, ERIK H. LARSEN, PAUL 0. MADSEN REGINALD C. BRUSKEWITZ
AND
From the William S. Middleton Veterans Administration Hospital and Department of Surgery, University of Wisconsin Clinical Sciences Center, Madison, Wisconsin
ABSTRACT
To evaluate the efficacy and safety of intracavernous self-injection of phentolamine and papaverine for the treatment of impotence, 30 patients were enrolled in a prospective, randomized, doubleblind, placebo-controlled cross-over study of papaverine and phentolamine versus normal saline. A total of 29 patients completed the study. The phentolamine plus papaverine combination resulted in erection in 24 patients (82.8 per cent) and no erection occurred after injection of saline. Of the patients 12 (41.4 per cent) experienced technical difficulties with the injection. Ecchymosis of the penis at the site of injection was common and 1 patient experienced priapism that resolved spontaneously. No other side effects occurred. Intracavernous self-injection with phentolamine and papaverine appears to be a safe and effective treatment of impotence but long-term effects must be determined. While the mechanism of penile erection still is debated1 recent studies have focused on the role of neurotransmitters in the corpus cavernosum. Vasoactive intestinal polypeptides2 may be involved in the neural control of penile erection and aadrenergic blocking agents, such as phenoxybenzamine, have been reported to cause penile erection when administered intracavernously. 3 Erections after intracavernous administration ofphenoxybenzamine last up to 30 hours. Conversely, erections with phentolamine, another a-blocker, are inconveniently brief. Intracavernous injection ofpapaverine, a smooth muscle relaxant, is reported to increase intracavernous pressure and penile volume for 10 to 120 minutes. 4 •5 Finally, with intracavernous injections of phentolamine and papaverine 2 to 3-hour erections have resulted. 6 To evaluate the safety and efficacy of intracavernous injections in patients with different etiologies of impotence, as well as patient compliance, a prospective, randomized, double-blind cross-over study ofphentolamine and papaverine versus normal saline was done.
and individual instruction in the injection technique during a single session as described previously. 6 One ml. tuberculine syringes with% or %-inch 25 gauge needles were used. No local anesthesia was used. Patients were randomized in double-blind fashion to selfadminister either 3 intracavernous injections of 1 ml. sterile normal saline on separate days, followed by 3 injections of 0.5 mg. phentolamine mesylate combined with 30 mg. papaverine hydrochloride on separate days, or vice versa. The date of injection, quality and duration of the erection, if present, and side effects were recorded. The quality of erection was defined as good when the penis was erect enough for penetration, partial when there was tumescence and rigidity of the penis not adequate enough for penetration, and absent when the patient reported no erection at all. After 3 and 6 injections patients returned to the clinic for examination of the penis and performance of liver enzyme studies. After 6 injections the code was broken. Patients with good results were offered a 1-month supply of the drug (10 ml.). Patients with partial or absent erections then were injected with papaverineandphentolamine in the office-by· a physician and the results were recorded. Patients with partial erections were reinstructed in the injection technique and they were offered a 1-month supply of 1.0 mg. phentolamine with 30 mg. papaverine, which in our experience sometimes provides a better result. Initial patients who experienced good erections by correct injection technique or higher dosage of phentolamine were considered to be technical failures. Conversely, if neither of these measures was successful the failure was considered as a drug failure.
MATERIAL AND METHODS
The study included 30 outpatients with impotence after written consent was obtained. All patients underwent thorough history taking and physical examination. A modified questionnaire as described by Nowinski and LoPiccolo7 was used to identify a psychogenic component for impotence. To assess penile blood flow penile Doppler studies were performed and the penile blood pressure index was calculated. 1 An index of less than 0.60 was considered to be pathological and 0.60 to 0.80 was considered to be pathological if there was additional evidence of vascular disease (for example a history of myocardial infarction). The serum testosterone level was measured and nocturnal penile tumescence devices (Snap-Gauge band*) 8 were given to the patients before treatment. However, since measurement of the testosterone leveP and nocturnal penile tumescence9 are of uncertain value these results were judged with reservation and they were not used for categorization of impotence. Patients with elevated liver enzymes, sickle cell anemia or a history of priapism were excluded. All patients were given general information about impotence, an overview of the study Accepted for publication November 4, 1986.
* Dacomed Corp., Minneapolis, Minnesota.
RESULTS
A total of 30 patients entered the study. There was 1 dropout owing to urgent hip surgery. The patient had used 3 injections of normal saline and he had reported no erections. Mean patient age was 60.9 ± 9.9 years (standard deviation). Mean duration of impotence was 4.8 ± 4.5 years and mean penile blood pressure index was 0.72 ± 0.14. Nocturnal penile tumescence devices revealed absent erections in 19 patients, slight morning erections in 3 and nonevaluable results in 8 owing to incorrect handling of the device.
678
__ cc----~~~-~---- _
•
---,
679
INTRACAVERNOUS SELF-INJECTION FOR TREATMENT OF IMPOTENCE TABLE 1.
Etiology of impotence in 29 patients and results of intracavernous self-injection
Etiology
No. Pts.
No. Good Erections
15
7
6
2 0
Vasculogenic Insulin-dependent diabetes mellitus N oninsulin-dependent diabetes mellitus Alcoholism After removal of penile prosthesis Proctocolectomy Cerebrovascular accident Unclear (possibly psychogenic) Unclear Totals
TABLE 2.
Good Partial Absent Total No.(%)
No. Pts. 12 7 10
29
4
8
12 (41.4)
0 1 1 0
29
12
12
1 0
No. Drug Failures 0 3 2
5 (17.2)
The distribution of the etiology of impotence is given in table 1. The quality of erection after self-injection is listed in table 2. None of the patients experienced erections after injection of normal saline. Among the 12 patients with a good erection 8 stated that the erection was as firm as before they became impotent and 4 noticed that it was not quite as good. There was no correlation between the etiology of impotence and technical or drug failures (table 1). All 12 patients with good results volunteered for the 1-month trial and they all continued to experience good results. However, 4 of these patients experienced some intermittent failures that they explained by inadequate injection technique. Of the 7 patients with partial erections 2 had a good erection after injection by the physician, and 2 achieved good erections with 1.0 mg. phentolamine and 30 mg. papaverine. Therefore, these 4 cases were considered technical failures. The remaining 3 patients were considered drug failures, since neither correct injection technique nor increased dosage of phentolamine could improve the quality of the erection. These patients included a 61-year-old insulin-dependent diabetic who also had suffered a stroke, a 74-year-old man with vasculogenic impotence and a 76-year-old man with unclear etiology of impotence. Of the 10 patients with absent erections after the 6 injections 9 underwent injection in the office. One patient refused injection and was considered a drug failure. Of the 9 physicianinjected patients 8 experienced good erections (technical failures) and 1 showed some tumescence and rigidity of the penis but presumably this was not enough for intercourse (drug failure). Of the 8 patients with technical failures 2 subsequently achieved good erections during the 1-month trial, 4 did not want to continue with the injections and 2 were not able to reproduce the results during the 1-month trial. Of the latter 2 patients a 67-year-old man previously had had 2 penile prostheses removed owing to infection. Careful injection by the physician resulted in an erection despite some fibrosis of the corpora cavernosa but the patient never managed to achieve erection during self-injection, perhaps because he could not avoid the fibrotic area. The other patient (63 years old) underwent injection twice by the physician with good results but he could not learn to perform the injection properly himself. The mean penile blood pressure index was 0.63 ± 0.13 in the drug failure group and 0.74 ± 0.13 in the remainder. The difference was statistically significant (Student's unpaired t test, p <0.005). Erections normally lasted 2 to 3 hours. However, some patients reported erections as short as 30 minutes and 1 patient
-· ------· ---· -- - l
2 2 0 0
0 1 1 0 0 0
No. Technical Failures 0
No. Drug Failures
6 2 2
2 1 1 1 1 1 1
Quality of erection after intracauernous phentolamine/ papauerine self-injection
Quality of Erection
No. Technical Failures
0 0 0
0 1
5
with psychogenic impotence reported an erection 26 hours in duration that passed spontaneously. Although he was informed beforehand of possible consequences of failure to seek treatment he did not consult a physician. Subsequent examination of the penis revealed no abnormality and the patient retained erectile ability with drug injection. No other cases of priapism occurred and no infections were noted. Most patients experienced varying degrees of ecchymosis at the site of injection. Although some patients reported mild discomfort in the penis during injection most were surprised at the lack of pain. No other local (for example fibrosis of the corpora cavernosa) or systemic (for example tachycardia, gastrointestinal symptoms or skin rash4) side effects occurred. Liver enzymes were not altered during the study. DISCUSSION
It has been stated that erection after intracavernous injection might have been reinforced psychologically.6 Our study demonstrates that there is little if any placebo effect of the injection. The combination of phentolamine and papaverine appears to be beneficial in the treatment of patients with impotence of varying etiologies. This finding suggests that lengthy and expensive evaluation might not be necessary before the treatment is initiated, since patients in all etiological groups may benefit from this technique. The injection technique can be learned by most patients. However, the high incidence of technical failure stresses the importance of careful instruction of the patient. Injection by the physician is worthwhile in patients who report absent erections after the injections. Increased dosage of phentolamine (or papaverine) should be attempted in patients with partial erection before alternative diagnostic or therapeutic measures are initiated. Lack of alteration of the liver enzymes suggests that patients with minimal liver damage no longer must be excluded from intracavernous injection. The significant difference of the penile blood pressure index between patients with good results and those who failed drug therapy, although basea on small numbers, might indicate that patients with impotence owing to compromised arterial blood supply to the penis may benefit less from intracavernous injections. This finding must be studied in larger series. Although the duration of the erection was satisfactory for most patients the 26-hour erection in 1 patient indicates that initial dosage reductions might be necessary in patients with nonvascular origins of impotence. 6 Intracavernous injections may facilitate the management of patients with psychogenic impotence. The patient with possible psychogenic impotence did not agree to undergo psychiatric consultation until after a full erection occurred with the injection. Although no true priapism occurred during this study one should be aware of this complication. Before surgical treatment1 is initiated intracavernous injection of an a-adrenergic drug or penile aspiration should be attempted. 6 Aspiration of approximately 10 ml. blood from the corpus cavernosum was successful in 1 patient with drug-induced priapism during a pilot study. 10
680
GASSER AND ASSOCIATES
CONCLUSION
lntracavernous self-injection of 0.5 mg. phentolamine and 30 mg. papaverine appears to be a safe and effective treatment of impotence. Future studies should focus on long-term effects of intracavernous injection, the pharmacological basis for the effect of these drugs, and the optimal concentration of phentolamine and papaverine, as well as other drug combinations. Drs. J. Bassadre, D. Goldrath, N. Pappas, J. Smith and G. Schmidt provided assistance. REFERENCES 1. Wagner, G. and Green, R.: Impotence. Physiological, Psychological, and Surgical Diagnosis and Treatment. New York: Plenum Press, 1981. 2. Willis, E., Ottesen, B., Wagner, G., Sundler, F. and Fahrenkrug, J.: Vasoactive intestinal polypeptide (VIP) as a possible neurotransmitter involved in penile erection. Acta Physiol. Scand., 113: 545, 1981. 3. Brindley, G. S.: Cavernosal alpha-blockade: a new technique for
4.
5. 6. 7. 8. 9.
10.
investigating and treating erectile impotence. Brit. J. Psychiat., 143: 332, 1983. Needleman, P. and Johnson, E. M., Jr.: Vasodilators and the treatment of angina. In: The Pharmacological Basis of Therapeutics, 6th ed. Edited by A. G. Goodman, L. S. Goodman and A. Z. Gilman. New York: MacMillan Publishing Co., Inc., sect. VI,chapt. 33,pp. 819-833, 1980. Virag, R.: lntracavernous injection of papaverine for erectile failure. Letter to the Editor. Lancet, 2: 938, 1982. Zorgniotti, A. W. and Lefleur, R. S.: Auto-injection of the corpus cavernosum with a vasoactive drug combination for vasculogenic impotence. J. Urol., 133: 39, 1985. Nowinski, J. K. and LoPiccolo, J.: Assessing sexual behavior in couples. J. Sex Marital Ther., 5: 225, 1979. Ek, A., Bradley, W. E. and Krane, R. J.: Nocturnal penile rigidity measured by the snap-gauge band. J. Urol., 129: 964, 1983. Condra, M., Morales, A., Surridge, D. H., Owen, J. A., Marshall, P. and Fenemore, J.: The unreliability of nocturnal penile tumescence recording as an outcome measurement in the treatment of organic impotence. J. Urol., 135: 280, 1986. Bruskewitz, R. C.: Clinical experience at University of Wisconsin Clinical Sciences Center, Urology Division. Unpublished data.
THE JOURNAL OF UROLOGY
Copyright© 1987 by The Williams & Wilkins Co.
Printed in U.S.A.
INTRACAVERNOUS SELF-INJECTION WITH PHENTOLAMINE AND PAPAVERINE FOR THE TREATMENT OF IMPOTENCE THOMAS C. GASSER, RICHARD M. ROACH, ERIK H. LARSEN, PAUL 0. MADSEN REGINALD C. BRUSKEWITZ
AND
From the William S. Middleton Veterans Administration Hospital and Department of Surgery, University of Wisconsin Clinical Sciences Center, Madison, Wisconsin
ABSTRACT
To evaluate the efficacy and safety of intracavernous self-injection of phentolamine and papaverine for the treatment of impotence, 30 patients were enrolled in a prospective, randomized, doubleblind, placebo-controlled cross-over study of papaverine and phentolamine versus normal saline. A total of 29 patients completed the study. The phentolamine plus papaverine combination resulted in erection in 24 patients (82.8 per cent) and no erection occurred after injection of saline. Of the patients 12 (41.4 per cent) experienced technical difficulties with the injection. Ecchymosis of the penis at the site of injection was common and 1 patient experienced priapism that resolved spontaneously. No other side effects occurred. Intracavernous self-injection with phentolamine and papaverine appears to be a safe and effective treatment of impotence but long-term effects must be determined. While the mechanism of penile erection still is debated1 recent studies have focused on the role of neurotransmitters in the corpus cavernosum. Vasoactive intestinal polypeptides2 may be involved in the neural control of penile erection and aadrenergic blocking agents, such as phenoxybenzamine, have been reported to cause penile erection when administered intracavernously. 3 Erections after intracavernous administration ofphenoxybenzamine last up to 30 hours. Conversely, erections with phentolamine, another a-blocker, are inconveniently brief. Intracavernous injection ofpapaverine, a smooth muscle relaxant, is reported to increase intracavernous pressure and penile volume for 10 to 120 minutes. 4 •5 Finally, with intracavernous injections of phentolamine and papaverine 2 to 3-hour erections have resulted. 6 To evaluate the safety and efficacy of intracavernous injections in patients with different etiologies of impotence, as well as patient compliance, a prospective, randomized, double-blind cross-over study ofphentolamine and papaverine versus normal saline was done.
and individual instruction in the injection technique during a single session as described previously. 6 One ml. tuberculine syringes with% or %-inch 25 gauge needles were used. No local anesthesia was used. Patients were randomized in double-blind fashion to selfadminister either 3 intracavernous injections of 1 ml. sterile normal saline on separate days, followed by 3 injections of 0.5 mg. phentolamine mesylate combined with 30 mg. papaverine hydrochloride on separate days, or vice versa. The date of injection, quality and duration of the erection, if present, and side effects were recorded. The quality of erection was defined as good when the penis was erect enough for penetration, partial when there was tumescence and rigidity of the penis not adequate enough for penetration, and absent when the patient reported no erection at all. After 3 and 6 injections patients returned to the clinic for examination of the penis and performance of liver enzyme studies. After 6 injections the code was broken. Patients with good results were offered a 1-month supply of the drug (10 ml.). Patients with partial or absent erections then were injected with papaverineandphentolamine in the office-by· a physician and the results were recorded. Patients with partial erections were reinstructed in the injection technique and they were offered a 1-month supply of 1.0 mg. phentolamine with 30 mg. papaverine, which in our experience sometimes provides a better result. Initial patients who experienced good erections by correct injection technique or higher dosage of phentolamine were considered to be technical failures. Conversely, if neither of these measures was successful the failure was considered as a drug failure.
MATERIAL AND METHODS
The study included 30 outpatients with impotence after written consent was obtained. All patients underwent thorough history taking and physical examination. A modified questionnaire as described by Nowinski and LoPiccolo7 was used to identify a psychogenic component for impotence. To assess penile blood flow penile Doppler studies were performed and the penile blood pressure index was calculated. 1 An index of less than 0.60 was considered to be pathological and 0.60 to 0.80 was considered to be pathological if there was additional evidence of vascular disease (for example a history of myocardial infarction). The serum testosterone level was measured and nocturnal penile tumescence devices (Snap-Gauge band*) 8 were given to the patients before treatment. However, since measurement of the testosterone leveP and nocturnal penile tumescence9 are of uncertain value these results were judged with reservation and they were not used for categorization of impotence. Patients with elevated liver enzymes, sickle cell anemia or a history of priapism were excluded. All patients were given general information about impotence, an overview of the study Accepted for publication November 4, 1986.
* Dacomed Corp., Minneapolis, Minnesota.
RESULTS
A total of 30 patients entered the study. There was 1 dropout owing to urgent hip surgery. The patient had used 3 injections of normal saline and he had reported no erections. Mean patient age was 60.9 ± 9.9 years (standard deviation). Mean duration of impotence was 4.8 ± 4.5 years and mean penile blood pressure index was 0.72 ± 0.14. Nocturnal penile tumescence devices revealed absent erections in 19 patients, slight morning erections in 3 and nonevaluable results in 8 owing to incorrect handling of the device.
678
__ cc----~~~-~---- _
•
---,
679
INTRACAVERNOUS SELF-INJECTION FOR TREATMENT OF IMPOTENCE TABLE 1.
Etiology of impotence in 29 patients and results of intracavernous self-injection
Etiology
No. Pts.
No. Good Erections
15
7
6
2 0
Vasculogenic Insulin-dependent diabetes mellitus N oninsulin-dependent diabetes mellitus Alcoholism After removal of penile prosthesis Proctocolectomy Cerebrovascular accident Unclear (possibly psychogenic) Unclear Totals
TABLE 2.
Good Partial Absent Total No.(%)
No. Pts. 12 7 10
29
4
8
12 (41.4)
0 1 1 0
29
12
12
1 0
No. Drug Failures 0 3 2
5 (17.2)
The distribution of the etiology of impotence is given in table 1. The quality of erection after self-injection is listed in table 2. None of the patients experienced erections after injection of normal saline. Among the 12 patients with a good erection 8 stated that the erection was as firm as before they became impotent and 4 noticed that it was not quite as good. There was no correlation between the etiology of impotence and technical or drug failures (table 1). All 12 patients with good results volunteered for the 1-month trial and they all continued to experience good results. However, 4 of these patients experienced some intermittent failures that they explained by inadequate injection technique. Of the 7 patients with partial erections 2 had a good erection after injection by the physician, and 2 achieved good erections with 1.0 mg. phentolamine and 30 mg. papaverine. Therefore, these 4 cases were considered technical failures. The remaining 3 patients were considered drug failures, since neither correct injection technique nor increased dosage of phentolamine could improve the quality of the erection. These patients included a 61-year-old insulin-dependent diabetic who also had suffered a stroke, a 74-year-old man with vasculogenic impotence and a 76-year-old man with unclear etiology of impotence. Of the 10 patients with absent erections after the 6 injections 9 underwent injection in the office. One patient refused injection and was considered a drug failure. Of the 9 physicianinjected patients 8 experienced good erections (technical failures) and 1 showed some tumescence and rigidity of the penis but presumably this was not enough for intercourse (drug failure). Of the 8 patients with technical failures 2 subsequently achieved good erections during the 1-month trial, 4 did not want to continue with the injections and 2 were not able to reproduce the results during the 1-month trial. Of the latter 2 patients a 67-year-old man previously had had 2 penile prostheses removed owing to infection. Careful injection by the physician resulted in an erection despite some fibrosis of the corpora cavernosa but the patient never managed to achieve erection during self-injection, perhaps because he could not avoid the fibrotic area. The other patient (63 years old) underwent injection twice by the physician with good results but he could not learn to perform the injection properly himself. The mean penile blood pressure index was 0.63 ± 0.13 in the drug failure group and 0.74 ± 0.13 in the remainder. The difference was statistically significant (Student's unpaired t test, p <0.005). Erections normally lasted 2 to 3 hours. However, some patients reported erections as short as 30 minutes and 1 patient
-· ------· ---· -- - l
2 2 0 0
0 1 1 0 0 0
No. Technical Failures 0
No. Drug Failures
6 2 2
2 1 1 1 1 1 1
Quality of erection after intracauernous phentolamine/ papauerine self-injection
Quality of Erection
No. Technical Failures
0 0 0
0 1
5
with psychogenic impotence reported an erection 26 hours in duration that passed spontaneously. Although he was informed beforehand of possible consequences of failure to seek treatment he did not consult a physician. Subsequent examination of the penis revealed no abnormality and the patient retained erectile ability with drug injection. No other cases of priapism occurred and no infections were noted. Most patients experienced varying degrees of ecchymosis at the site of injection. Although some patients reported mild discomfort in the penis during injection most were surprised at the lack of pain. No other local (for example fibrosis of the corpora cavernosa) or systemic (for example tachycardia, gastrointestinal symptoms or skin rash4) side effects occurred. Liver enzymes were not altered during the study. DISCUSSION
It has been stated that erection after intracavernous injection might have been reinforced psychologically.6 Our study demonstrates that there is little if any placebo effect of the injection. The combination of phentolamine and papaverine appears to be beneficial in the treatment of patients with impotence of varying etiologies. This finding suggests that lengthy and expensive evaluation might not be necessary before the treatment is initiated, since patients in all etiological groups may benefit from this technique. The injection technique can be learned by most patients. However, the high incidence of technical failure stresses the importance of careful instruction of the patient. Injection by the physician is worthwhile in patients who report absent erections after the injections. Increased dosage of phentolamine (or papaverine) should be attempted in patients with partial erection before alternative diagnostic or therapeutic measures are initiated. Lack of alteration of the liver enzymes suggests that patients with minimal liver damage no longer must be excluded from intracavernous injection. The significant difference of the penile blood pressure index between patients with good results and those who failed drug therapy, although basea on small numbers, might indicate that patients with impotence owing to compromised arterial blood supply to the penis may benefit less from intracavernous injections. This finding must be studied in larger series. Although the duration of the erection was satisfactory for most patients the 26-hour erection in 1 patient indicates that initial dosage reductions might be necessary in patients with nonvascular origins of impotence. 6 Intracavernous injections may facilitate the management of patients with psychogenic impotence. The patient with possible psychogenic impotence did not agree to undergo psychiatric consultation until after a full erection occurred with the injection. Although no true priapism occurred during this study one should be aware of this complication. Before surgical treatment1 is initiated intracavernous injection of an a-adrenergic drug or penile aspiration should be attempted. 6 Aspiration of approximately 10 ml. blood from the corpus cavernosum was successful in 1 patient with drug-induced priapism during a pilot study. 10
680
GASSER AND ASSOCIATES
CONCLUSION
lntracavernous self-injection of 0.5 mg. phentolamine and 30 mg. papaverine appears to be a safe and effective treatment of impotence. Future studies should focus on long-term effects of intracavernous injection, the pharmacological basis for the effect of these drugs, and the optimal concentration of phentolamine and papaverine, as well as other drug combinations. Drs. J. Bassadre, D. Goldrath, N. Pappas, J. Smith and G. Schmidt provided assistance. REFERENCES 1. Wagner, G. and Green, R.: Impotence. Physiological, Psychological, and Surgical Diagnosis and Treatment. New York: Plenum Press, 1981. 2. Willis, E., Ottesen, B., Wagner, G., Sundler, F. and Fahrenkrug, J.: Vasoactive intestinal polypeptide (VIP) as a possible neurotransmitter involved in penile erection. Acta Physiol. Scand., 113: 545, 1981. 3. Brindley, G. S.: Cavernosal alpha-blockade: a new technique for
4.
5. 6. 7. 8. 9.
10.
investigating and treating erectile impotence. Brit. J. Psychiat., 143: 332, 1983. Needleman, P. and Johnson, E. M., Jr.: Vasodilators and the treatment of angina. In: The Pharmacological Basis of Therapeutics, 6th ed. Edited by A. G. Goodman, L. S. Goodman and A. Z. Gilman. New York: MacMillan Publishing Co., Inc., sect. VI,chapt. 33,pp. 819-833, 1980. Virag, R.: lntracavernous injection of papaverine for erectile failure. Letter to the Editor. Lancet, 2: 938, 1982. Zorgniotti, A. W. and Lefleur, R. S.: Auto-injection of the corpus cavernosum with a vasoactive drug combination for vasculogenic impotence. J. Urol., 133: 39, 1985. Nowinski, J. K. and LoPiccolo, J.: Assessing sexual behavior in couples. J. Sex Marital Ther., 5: 225, 1979. Ek, A., Bradley, W. E. and Krane, R. J.: Nocturnal penile rigidity measured by the snap-gauge band. J. Urol., 129: 964, 1983. Condra, M., Morales, A., Surridge, D. H., Owen, J. A., Marshall, P. and Fenemore, J.: The unreliability of nocturnal penile tumescence recording as an outcome measurement in the treatment of organic impotence. J. Urol., 135: 280, 1986. Bruskewitz, R. C.: Clinical experience at University of Wisconsin Clinical Sciences Center, Urology Division. Unpublished data.