Experience with buccal phentolamine mesylate for impotence
Int Journal of Impotence Research, 1994, 6, 37-41
A.W. Zorgniotti, M.D. (Remember the one in Zonagen's patent)
Materials and Methods: All patients complained of erectile dysfunction which obviated vaginal penetration or was characterized by inability to maintain erection, without ejaculation, upon initiation of vaginal penetration (mean time of impotence: 3.4 years. Range 0.5-35).
A detailed history was taken and genital examination performed.
A tentative etiologic diagnosis was assigned to each patient.
Age and diagnosis were generally not a factor in admission to the trials. As a result, patients with vascular and non specific causes were admitted as were those with diabetes mellitus. However, extreme age or severe panile vascular insufficiency resulted in exclusion. Patients with a history of ischemic heart disease were required to obtain permission from their cardiologist to participate.
The Trials
These were done at different times and with different patients. Only those patients who followed the protocol were considered for analysis.
The most common cause for being dropped was failure to take medication, often for lack of a partner. Losing the medication was also a reason given and this was not replaced. The patients were asked to take the medication as per protocol. Emphasis was placed on the requirement to have coitus and not to expect spontaneous erection without this. Side effects were enumerated: eg stuffy nose, dizziness and faintness. In trial 2 alcohol ingestion was prohibited at the time of taking the drug and until after coitus.
Open Label Trial 1. Phentolamine HCL 50 mg (white tablet)vs Phenoxybenzmine 10mg (red capsule) po: 98 patients were asked to take each drug at least three days apart and 1.5 hours before attempting coitus. 85 patients were suitable for evaluation. Mean age 56 (29-72).
Single Blind Trial 2. Phentolamine mesylate 20mg buccal tablet vs Lactose placebo buccal tablet: 83 patients were asked to place the tablet between the gum and cheek 20-30 minutes before coitus, each on a different day. Patients were advised not to consume alcohol, not to swallow the tablet and not to expect erection without coitus. In the event of failure, patients on intracavernous self injection were told that they could proceed within an hour of the failed coitus. Sixty nine patients were suitable for evaluation. Mean age 57.5 (25-74).
Patients who were told that either tablet might prove beneficial were askedto report resluts: no erection, partial erection, erection with penetration or reversal of failure to maintain erection. Side effects were also the subject of inquiry.
Results
Trial 1 showed that 42%(full erections 36 of 85)were able to erect for intercourse with phentolamine HCL.(partial erections 15 of 85, and no erections 34 of 85).
While 9% had a favorable result with phenoxybenzamine (full erections 8 of 85, partial 5 of 85, and none 74 of 85)had a favorable result with phenoxybenzamine. An equal number of patients were unable to erect. Partial erections were encountered but not counted as successes.
Trial 2. showed a 32% success buccal phentolamine (full 22 of 69, partial 9 of 69, none 38 of 69 ). Placebo 13% (full 9 of 69, partial 2 of 69, none 58 of 69).
Side effects: stuffy nose 6%, faintness or dizziness 2.3% (relieved by lying down for 10 to 15 minutes); vomiting less than 0.01%.
Please note that there are parts of the article that I did not included in this report. Also, there was a "penile dorsal artery velocity" part in the study that I did not copy.
Additional comments from the author himself:
" Alcohol ingestion abolishes the erectile effect of buccal medication".(phentolamine)
(oral phentolamine)"it does not interfere with ejaculation as penile injections often do".
"prolonged erection (priapism)has not been noted with administration of oral or buccal phentolamine".
"administration of oral or buccal phentolamine for impotence appears safe, producing minimal transitory hypotension in some patients". |
