The Effect of Sildenafil and Tadalafil on Skeletal Muscle and Perceptual Fatigue

The Effect of Sildenafil and Tadalafil on Skeletal Muscle and Perceptual Fatigue.

This study is funded by the Moody Endowment. In this project, we will investigate the potential effect of skeletal muscle nitric oxide (NO) production on skeletal muscle anabolism, muscle strength, physical function, and body composition in older individuals. Further, we will determine whether augmentation of NO-mediated signaling reduces fatigue and fatigability.

Study Overview

• Status: Completed
• Conditions: Fatigue
• Intervention / Treatment: Drug: Sildenafil; Drug: Placebo; Drug: tadalafil

Detailed Description

The Investigators hypothesize that upregulation of skeletal muscle NO-cGMP mediated responses through phosphodiesterase (PDE) inhibition by sildenafil or tadalafil causes an acute anabolic response of skeletal muscle protein synthesis. NO is well-known to elicit vasodilation through stimulation of cGMP signaling, and NO-mediated changes in muscle perfusion may influence both skeletal muscle anabolism and perceptual fatigue. To measure skeletal muscle protein synthesis, we will infuse a stable isotope tracer of phenylalanine and measure its incorporation into skeletal muscle proteins following a dose of sildenafil, tadalafil, or placebo. The Investigators will also determine whether differences exist between men and women in response to PDE inhibition. As skeletal muscle NO-cGMP signaling has been implicated in fatigue responses, we will assess the acute effect of sildenafil and tadalafil on fatigue. Fatigue can be manifested both as a performance deficit at a local level (e.g., a reduced ability of skeletal muscle to produce power or force) as well as a subjective experience of lacking physical or mental energy. Accordingly, we will use more than one means (skeletal muscle performance, fatigue questionnaires, accelerometers) to study fatigue. The Investigators hypothesize that sildenafil or tadalafil will acutely reduce exercise-associated fatigability and skeletal muscle fatigue development

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Galveston, Texas, United States, 77555-0361
      • University of Texas Medical Branch

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 48 years to 58 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Age 50-60 years of age
2. Ability to sign consent form (score>23 on the 30-item Mini Mental Status examination, MMSE)
3. Stable body weight for at least three months.

Exclusion Criteria:

1. Physical dependence or frailty (impairment in any of the Activities of Daily Living (ADL), history of falls (>2/year) or significant weight loss in the past year).
2. Pregnancy
3. Significant heart, liver, kidney, blood or respiratory disease.
4. Peripheral vascular disease.
5. Diabetes mellitus or other untreated endocrine disease.
6. Active cancer
7. Use of nitrates.
8. Recent (within 6 months) treatment with anabolic steroids, or corticosteroids.
9. Alcohol or drug abuse.
10. Severe depression (>5 on the 15-item Geriatric Depression Scale, GDS).
11. Cardiac abnormalities such as cardiac shunt or previously diagnosed pulmonary hypertension.
12. Systolic blood pressure <100 or>150, diastolic blood pressure <60 or 90>. This range is smaller than the acceptable range stated in the prescribing information for sildenafil/tadalafil (90/50 and <170/110).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Sildenafil / Placebo; 50 mg/day Sildenafil: (Other Name: Viagra, Revatio) for weeks 0-4. Placebo for weeks 5-8.	Drug: Sildenafil; 50 mg/day for 4 weeks; Other Names: Viagra; Revatio; Drug: Placebo; Placebo 1 capsule per day for four weeks.
Active Comparator: Tadalafil / Placebo; 10 mg/day Tadalafil: (Other Name: Cialis, Adcirca) for weeks 0-4. Placebo for weeks 5-8.	Drug: Placebo; Placebo 1 capsule per day for four weeks.; Drug: tadalafil; 10 mg/day for 4 weeks.; Other Names: Cialis; Adcirca
Active Comparator: Placebo / Sildenafil; Placebo for weeks 0-4. 50 mg/day Sildenafil: (Other Name: Viagra, Revatio) for weeks 5-8.	Drug: Sildenafil; 50 mg/day for 4 weeks; Other Names: Viagra; Revatio; Drug: Placebo; Placebo 1 capsule per day for four weeks.
Active Comparator: Placebo / Tadalafil; Placebo for weeks 0-4. 10 mg/day Tadalafil: (Other Name: Cialis, Adcirca) for weeks 5-8.	Drug: Placebo; Placebo 1 capsule per day for four weeks.; Drug: tadalafil; 10 mg/day for 4 weeks.; Other Names: Cialis; Adcirca

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Skeletal Muscle Fatigue as Measured by Biodex 4 Pro After 4 Weeks of Placebo	Isokinetic Fatigue Measure (knee extension) is measured on a Biodex System Pro 4 within a 75 degree range of motion. Subjects performed concentric contractions at a fixed speed of 120 degree/sec. 50 contractions were performed at 100% force, one contraction every second. Isokinetic fatigue will be measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug. Data is presented as mean maximum force over all 50 kicks.	after 4 weeks of placebo
Skeletal Muscle Fatigue as Measured by Biodex 4 Pro After 4 Weeks of Active Drug	Isokinetic Fatigue Measure (knee extension) is measured on a Biodex System Pro 4 within a 75 degree range of motion. Subjects performed concentric contractions at a fixed speed of 120 degree/sec. 50 contractions were performed at 100% force, one contraction every second. Isokinetic fatigue will be measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug. Data is presented as mean maximum force over all 50 kicks.	after 4 weeks of active drug
Exercised Induced Fatigability as Measured by Fatigue Rating Scale After 4 Weeks of Placebo	The fatigue rating scale is a scale from 0 to 10 with 0 being no fatigue at all and 10 being the worst fatigue the subject can imagine. The subject is asked to rate their level of fatigue in their leg. This test was performed before and immedicately after the Biodex leg fatigue test after 4 weeks of placebo. Data is presented as change in scale from pre fatigue test to post fatigue test, with a higher score indicating a greater level of fatigue.	after 4 weeks of placebo
Exercised Induced Fatigability as Measured by Fatigue Rating Scale After 4 Weeks of Active Drug	The fatigue rating scale is a scale from 0 to 10 with 0 being no fatigue at all and 10 being the worst fatigue the subject can imagine. The subject is asked to rate their level of fatigue in their leg. This test was performed before and immedicately after the Biodex leg fatigue test. Data is presented as change in scale from pre fatigue test to post fatigue test, with a higher score indicating a greater level of fatigue.	after 4 weeks of active drug

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum Peak Isometric Leg Strength as Measured by Biodex Pro4 After 4 Weeks of Placebo	Peak isometric strength is measured on a Biodex System 4 Pro. This test is isolated to the quadricep muscle of one leg. Isometric test is performed at 90 degrees with 5 seconds of force production for each contraction and 15 seconds of rest. 1 set of 3 contractions at 100% force performed. Isometric strength was measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of placebo
Maximum Peak Isometric Leg Strength as Measured by Biodex Pro4 After 4 Weeks of Active Drug.	Peak isometric strength is measured on a Biodex System 4 Pro. This test is isolated to the quadricep muscle of one leg. Isometric test is performed at 90 degrees with 5 seconds of force production for each contraction and 15 seconds of rest. 1 set of 3 contractions at 100% force performed. Isometric strength was measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of active drug
Maximum Peak Isokinetic Leg Strength as Measured by Biodex Pro4 After 4 Weeks of Placebo.	Isokinetic strength (knee extension) is measured on a Biodex System Pro 4 within a 75 degree range of motion. Subjects performed concentric contractions at a fixed speed of 120 degree/sec. 1 set of 3 contractions were performed at 100% force. Isokinetic strength will be measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of placebo
Maximum Peak Isokinetic Leg Strength as Measured by Biodex Pro4 After 4 Weeks of Active Drug	Isokinetic strength (knee extension) is measured on a Biodex System Pro 4 within a 75 degree range of motion. Subjects performed concentric contractions at a fixed speed of 120 degree/sec. 1 set of 3 contractions were performed at 100% force. Isokinetic strength will be measured at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of active drug
Lean Body Mass as Measured by Dual Energy X-ray Absorptiometry at Week 0.	Lean Body Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 0
Lean Body Mass as Measured by Dual Energy X-ray Absorptiometry at Week 4.	Lean Body Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 4
Lean Body Mass as Measured by Dual Energy X-ray Absorptiometry at Week 8.	Lean Body Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 8
Fat Mass as Measured by Dual Energy X-ray Absorptiometry at Week 0.	Fat Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 0
Fat Mass as Measured by Dual Energy X-ray Absorptiometry at Week 4.	Fat Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 4
Fat Mass as Measured by Dual Energy X-ray Absorptiometry at Week 8.	Fat Mass is calculated from a whole body scan measured on a dual energy x-ray absorptiometry.	week 8
Walking Distance at 100% Effort as Measured by Walking Test After 4 Weeks of Placebo	Walking performance will be assessed during 2 minutes of walking in long corridor hallways. Subjects will be asked to walk at 100% effort (as quickly as they can safely walk without running) for 2 minutes. Distance traveled for the 2 minutes will be recorded. The walking test will be completed at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of placebo
Walking Distance at 100% Effort as Measured by Walking Test After 4 Weeks of Active Drug	Walking performance will be assessed during 2 minutes of walking in long corridor hallways. Subjects will be asked to walk at 100% effort (as quickly as they can safely walk without running) for 2 minutes. Distance traveled for the 2 minutes will be recorded. The walking test will be completed at week 4 and week 8. Depending on grouping, the week 4 and week 8 measures may be placebo or active drug. Data will be reported as after 4 weeks of placebo or after 4 weeks of active drug.	after 4 weeks of active drug
Perceptual Fatigue as Measured by Multidimensional Fatigue Symptom Inventory - Short Form Total Score at Week 0	Fatigue symptoms will be measured using the 30-item Multidimensional Fatigue Symptom Inventory - Short Form, a validated measure that yields one overall score of total fatigue calculated using five sub scales (general, physical, emotional, mental, vigor). With the exception of the vigor sub scale, higher scores indicate greater fatigue. Total fatigue score is calculated by summing the sub categories (general, physical, emotional and mental) and subtracting vigor. Total scores range from -24 to 96, with a higher score indicating more fatigue.	Week 0
Perceptual Fatigue as Measured by Multidimensional Fatigue Symptom Inventory - Short Form Total Score at Week 4	Fatigue symptoms will be measured using the 30-item Multidimensional Fatigue Symptom Inventory - Short Form, a validated measure that yields one overall score of total fatigue calculated using five sub scales (general, physical, emotional, mental, vigor). With the exception of the vigor sub scale, higher scores indicate greater fatigue. Total fatigue score is calculated by summing the sub categories (general, physical, emotional and mental) and subtracting vigor. Total scores range from -24 to 96, with a higher score indicating more fatigue.	week 4
Perceptual Fatigue as Measured by Multidimensional Fatigue Symptom Inventory - Short Form Total Score at Week 8	Fatigue symptoms will be measured using the 30-item Multidimensional Fatigue Symptom Inventory - Short Form, a validated measure that yields one overall score of total fatigue calculated using five sub scales (general, physical, emotional, mental, vigor). With the exception of the vigor sub scale, higher scores indicate greater fatigue. Total fatigue score is calculated by summing the sub categories (general, physical, emotional and mental) and subtracting vigor. Total scores range from -24 to 96, with a higher score indicating more fatigue.	week 8

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hemoglobin Level at Week 0	Hemoglobin was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 11.6 - 15.0 g/dL.	week 0
Hemoglobin Level Measured at Week 4	Hemoglobin was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 11.6 - 15.0 g/dL.	week 4
Hemoglobin Level Measured at Week 8	Hemoglobin was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 11.6 - 15.0 g/dL.	week 8
Hematocrit Level Measured at Week 0	Hematocrit was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 35.7 - 45.2%.	week 0
Hematocrit Level Was Measured at 4 Weeks	Hematocrit was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 35.7 - 45.2%.	4 weeks
Hematocrit Level Measured at Week 8	Hematocrit was measured by University of Texas Medical Branch Clinical Laboratory. Normal ranges are 35.7 - 45.2%.	week 8

Collaborators and Investigators

• Sponsor: The University of Texas Medical Branch, Galveston
• Investigators: Principal Investigator: Melinda Sheffield-Moore, PhD, University of Texas medical branch, Galveston

Study record dates

Study Major Dates

• Study Start: November 1, 2012
• Primary Completion (Actual): June 1, 2015
• Study Completion (Actual): June 1, 2015

Study Registration Dates

• First Submitted: August 7, 2012
• First Submitted That Met QC Criteria: August 8, 2012
• First Posted (Estimate): August 9, 2012

Study Record Updates

• Last Update Posted (Actual): July 17, 2018
• Last Update Submitted That Met QC Criteria: June 19, 2018
• Last Verified: April 1, 2018

More Information

Terms related to this study

• Keywords: Fatigue; Tadalafil; Placebo; Accelerometer; Sildenafil; Infusion; Fatigability; Nitric Oxide (NO); Isotope; Surface Electromyography (sEMG); cyclic guanosine monophosphate (cGMP); NO-cGMP; Phosphodiesterase (PDE); Anabolism; Upregulation; Nitrosylation
• Additional Relevant MeSH Terms: Fatigue; Molecular Mechanisms of Pharmacological Action; Vasodilator Agents; Urological Agents; Enzyme Inhibitors; Phosphodiesterase Inhibitors; Phosphodiesterase 5 Inhibitors; Sildenafil Citrate; Tadalafil
• Other Study ID Numbers: 12-153