CompletedNCT00598585Updated Jun 27, 2017Results posted

Use of Sildenafil (Viagra) to Alter Fatigue, Functional Status and Impaired Cerebral Blood Flow in Patients With CFS

A Phase 4 interventional study of Sildenafil (Viagra) and Placebo in Chronic Fatigue Syndrome, sponsored by Charles Drew University of Medicine and Science. Completed at 1 site in United States. Open to participants aged 18 Years to 49 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2017-06-27.

Sponsored by Charles Drew University of Medicine and Science · Phase 4, Interventional, and Treatment

Phase: Phase 4
Study type: Interventional
Enrollment: 12
Allocation: Randomized
Ages: 18 Years to 49 Years
Sex: All

Study summary

Use of Viagra to Alter Symptoms in Patients with Chronic Fatigue Syndrome (CFS)

Read the detailed description

Use of Sildenafil (Viagra) to Alter Fatigue, Functional Status and Impaired Cerebral Blood Flow in Patients with Chronic Fatigue Syndrome.

Conditions studied

Chronic Fatigue Syndrome

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In context

Fatigue Syndrome, Chronic

246 studies on the registry are indexed under Fatigue Syndrome, Chronic; 58 are open to participants now.

This study's enrollment of 12 is below the median of 60 across 166 interventional studies indexed under Fatigue Syndrome, Chronic.

Browse Fatigue Syndrome, Chronic studies →

Lead sponsor

Charles Drew University of Medicine and Science is the lead sponsor of 41 studies on the registry; 1 is open to participants now.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years to 49 Years
Sexes eligible: All
Accepts healthy volunteers: Yes

Inclusion criteria

Patients meeting the CDC definition of CFS.
All races, ethnicities, socio-economic status (SES), and gender
Age greater than 18 (because of concerns about radioactivity, we and the Cedars-Sinai and Harbor-UCLA IRBs have decided not to enroll subjects below the age of 18).
Age less than 50. Because of concern of sildenafil exacerbating coronary artery disease, we will only enroll patients younger than 50.
Able to provide informed consent.
Willingness to be off all medicines and supplements for 3 weeks prior to the study.
Patients with psychiatric disorders (see below) will be included, if they could be off their medications, and if their psychiatric diagnosis clearly occurred after their fatigue symptoms began.
Patients with concurrent fibromyalgia will be allowed to participate if the meet diagnostic criteria for CFS.

Exclusion criteria

Exclusion Criteria:

Disabilities that would prevent them from participating in the study.
Current use of prescription medicines (starting at 3 weeks prior to the study) and supplements (starting at 1 weeks prior to the study) except acetaminophen or aspirin. This includes herbal supplements and vitamins.
Existing medical illnesses, such as heart disease, hypertension, cancer, rheumatological diseases, endocrinopathies or hormone replacement therapy, seizure disorders, severe obesity (BMI > 32 kg/m2),
Severe psychiatric disorders including bipolar disorder, schizophrenia, dementia and previous or current diagnosis of alcohol or substance abuse within the past year. Patients with depression of such severity as to warrant treatment with anti-depressants will be excluded.
Current abuse of illicit drugs or heavy ethanol use.
Pregnant women will be excluded because of radioactivity exposure from the SPECT scans.
Abnormal EKG
Abnormal CBC, blood chemistries, thyroid function tests, and HIV, ANA, RF and ESR tests.

Study design

Phase: Phase 4
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Double (Participant, Investigator)
Enrollment: 12 participants (actual)

Study arms

Experimental
sidenafil
sidenafil
Drug: Sildenafil (Viagra)
Placebo comparator
placebo
placebo
Drug: Placebo

Interventions

DrugSildenafil (Viagra)
25 mg tid of either Sildenafil(Viagra) for first week. 50 mg tid of either Sildenafil (Viagra) for second week. 100 mg tid of either Sildenafil (Viagra) 3rd,4th, 5th and 6th week of study participation.
DrugPlacebo
Placebo pills 3X/day for 6 weeks

What researchers measure

Primary outcomes

Change in Fatigue Impact Scale at 6 Weeks
change in fatigue impact scale there are 42 questions. Each question can be answered from 0 (no problem) to 4 (extreme problem), so a higher score indicates more severe fatigue impact. minimum score=0, maximum score =148 values are calculated at baseline and 6 months and the score at 6 months compared to baseline months is calculated
Time frame: 6 weeks

Results

Posted Jun 27, 2017

Limitations and caveats

small number of subjects enrolled in trial

Participant flow

Participant flow — Overall Study
Milestone	Sildenafil	Placebo
Started	6	6
Completed	5	6
Not completed	1	0
Withdrew: Lost to follow-up	1	0

Outcome measures

PrimaryChange in Fatigue Impact Scale at 6 Weeks

change in fatigue impact scale there are 42 questions. Each question can be answered from 0 (no problem) to 4 (extreme problem), so a higher score indicates more severe fatigue impact. minimum score=0, maximum score =148 values are calculated at baseline and 6 months and the score at 6 months compared to baseline months is calculated

Time frame:: 6 weeks
Reported as:: Mean · units on a scale

Change in Fatigue Impact Scale at 6 Weeks
units on a scale	Sildenafil	Placebo
Change in Fatigue Impact Scale at 6 Weeks	-32.6 ± 31.5	-1.5 ± 12.2

Statistical analysis

Sildenafil vs Placebo · t-test, 2 sided · p = < 0.05

Adverse events

Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
Sildenafil	—	0/5 (0%)	1/5 (20%)
Placebo	—	0/6 (0%)	0/6 (0%)

Most frequent other events

Most frequent other events
Event	Sildenafil	Placebo
dizzinessCardiac disorders	1/5	0/6

Baseline characteristics

Age, Continuous
Age, Continuous(years)	Sildenafil	Placebo	Total
Mean	39 ± 6	38 ± 9	38 ± 5

Sex: Female, Male
Sex: Female, Male(Participants)	Sildenafil	Placebo	Total
Female	5	4	9
Male	1	2	3

Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)	Sildenafil	Placebo	Total
Hispanic or Latino	1	2	3
Not Hispanic or Latino	5	4	9
Unknown or Not Reported	0	0	0

Race (NIH/OMB)
Race (NIH/OMB)(Participants)	Sildenafil	Placebo	Total
American Indian or Alaska Native	0	0	0
Asian	0	0	0
Native Hawaiian or Other Pacific Islander	0	0	0
Black or African American	0	0	0
White	6	6	12
More than one race	0	0	0
Unknown or Not Reported	0	0	0

Study locations

1 site

Charles Drew University of Medicine and Science
Los Angeles, California 90059, United States

References and documents

Individual participant data

Plan to share: No

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Jun 27, 2017, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT00598585
Lead sponsor: Charles Drew University of Medicine and Science
Collaborators: Pfizer
Responsible party: Theodore Friedman (Professor, Charles Drew University of Medicine and Science) — Principal investigator
First posted: Jan 22, 2008
Start date: Jul 2002
Primary completion: Dec 2010
Completion: Dec 2010
Results posted: Jun 27, 2017
Last update: Jun 27, 2017

Study contacts

Ted C Friedman, M.D., Ph.D.

principal investigator · Charles Drew University of Medicine and Science

Oversight

Data monitoring committee: Yes

View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Apr 2017. You cannot join it, but the record below documents what was studied.

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