This is taken directly from Pfizer's web page on Viagra at www.viagra.com
Effect of VIAGRA and placebo on
maintenance of erection by baseline score.
The frequency of patients reporting
improvement of erections in response to a
global question in four of the randomized,
double-blind, parallel, placebo-controlled fixed
dose studies (1797 patients) of 12 to 24 weeks
duration is shown in Figure 2. These patients
had erectile dysfunction at baseline that was
characterized by median categorical scores of
2 (a few times) on principal IIEF questions.
Erectile dysfunction was attributed to organic
(58%; generally not characterized, but including
diabetes and excluding spinal cord injury),
psychogenic (17%), or mixed (24%) etiologies.
Sixty-three percent, 74%, and 82% of the
patients on 25 mg, 50 mg and 100 mg of
VIAGRA, respectively, reported an improvement
in their erections, compared to 24% on placebo.
In the titration studies (n=644) (with most
patients eventually receiving 100 mg), results
were similar.
Figure 2. Percentage of Patients Reporting an
Improvement in Erections.
The patients in studies had varying degrees of
ED. One- third to one-half of the subjects in
these studies reported successful intercourse
at least once during a 4-week, treatment-free
run-in period.
ÿÿIn many of the studies, of both fixed dose and
titration designs, daily diaries were kept by
patients. In these studies, involving about 1600
patients, analyses of patient diaries showed no
effect of VIAGRA on rates of attempted
intercourse (about 2 per week), but there was
clear treatment-related improvement in sexual
function: per patient weekly success rates
averaged 1.3 on 50-100 mg of VIAGRA vs 0.4 on
placebo; similarly, group mean success rates
(total successes divided by total attempts)
were about 66% on VIAGRA vs about 20% on
placebo.
During 3 to 6 months of double-blind treatment
or longer-term (1 year), open-label studies,
few patients withdrew from active treatment
for any reason, including lack of effectiveness.
At the end of the long-term study, 88% of
patients reported that VIAGRA improved their
erections.
ÿÿMen with untreated ED had relatively low
baseline scores for all aspects of sexual
function measured (again using a 5-point scale)
in the IIEF. VIAGRA improved these aspects of
sexual function: frequency, firmness and
maintenance of erections; frequency of orgasm;
frequency and level of desire; frequency,
satisfaction and enjoyment of intercourse; and
overall relationship satisfaction.
One randomized, double-blind, flexible-dose,
placebo-controlled study included only patients
with erectile dysfunction attributed to
complications of diabetes mellitus (n=268). As
in the other titration studies, patients were
started on 50 mg and allowed to adjust the
dose up to 100 mg or down to 25 mg of VIAGRA;
all patients, however, were receiving 50 mg or
100 mg at the end of the study. There were
highly statistically significant improvements
on the two principal IIEF questions (frequency
of successful penetration during sexual
activity and maintenance of erections after
penetration) on VIAGRA compared to placebo. On
a global improvement question, 57% of VIAGRA
patients reported improved erections versus
10% on placebo. Diary data indicated that on
VIAGRA, 48% of intercourse attempts were
successful versus 12% on placebo.
ÿÿOne randomized, double-blind,
placebo-controlled, crossover, flexible-dose
(up to 100 mg) study of patients with erectile
dysfunction resulting from spinal cord injury
(n=178) was conducted. The changes from
baseline in scoring on the two end point
questions (frequency of successful penetration
during sexual activity and maintenance of
erections after penetration) were highly
statistically significantly in favor of VIAGRA.
On a global improvement question, 83% of
patients reported improved erections on
VIAGRA versus 12% on placebo. Diary data
indicated that on VIAGRA, 59% of attempts at
sexual intercourse were successful compared
to 13% on placebo.
ÿÿAcross all trials, VIAGRA improved the
erections of 43% of radical prostatectomy
patients compared to 15% on placebo.
ÿÿSubgroup analyses of responses to a global
improvement question in patients with
psychogenic etiology in two fixed-dose studies
(total n=179) and two titration studies (total
n=149) showed 84% of VIAGRA patients
reported improvement in erections compared
with 26% of placebo. The changes from baseline
in scoring on the two end point questions
(frequency of successful penetration during
sexual activity and maintenance of erections
after penetration) were highly statistically
significantly in favor of VIAGRA. Diary data in
two of the studies (n=178) showed rates of
successful intercourse per attempt of 70% for
VIAGRA and 29% for placebo.
ÿÿA review of population subgroups
demonstrated efficacy regardless of baseline
severity, etiology, race and age. VIAGRA was
effective in a broad range of ED patients,
including those with a history of coronary
artery disease, hypertension, other cardiac
disease, peripheral vascular disease, diabetes
mellitus, depression, coronary artery bypass
graft (CABG), radical prostatectomy,
trans-urethral resection of the prostate (TURP)
and spinal cord injury, and in patients taking
anti-depressants/anti-psychotics and
anti-hypertensives/diuretics.
Also, the 3% vision impairment was listed as mild and transient. It is not clinically significant enough to warrent approval of Vasomax. |
