Schizophrenia
Conditions
Keywords
Schizophrenia, Cognition, Sildenafil, PDE5 Inhibitor
Brief summary
The study is a double-blind, placebo-controlled, random-order, single-dose crossover trial of sildenafil 50 & 100 mg added to stable antipsychotic treatment in schizophrenia patients to assess whether this PDE5 inhibitor improves cognitive functioning (including verbal memory, fluency, attention, spatial memory, motor speed, and executive function) and clinical symptoms (psychotic, negative, mood symptoms, and self-reports of side-effects).
Detailed description
Specific Aims: 1. Evaluate the effects of single doses of sildenafil 50 & 100 mg compared to placebo on cognitive functioning, including verbal memory, fluency, attention, spatial memory, motor speed, and executive function. 2. Evaluate the effects of single doses of sildenafil 50 & 100 mg compared to placebo on psychotic, negative, and mood symptoms. 3. Assess self-reports of side effects of sildenafil 50 & 100 mg. Location and Subjects: 25 adult outpatients with schizophrenia will be recruited from the Massachusetts General Hospital outpatient clinic or the Freedom Trail Clinic of the Lindemann Center. All research procedures will be performed at the Psychopharmacology Clinic of the Massachusetts General Hospital. Subjects must be English speaking because the cognitive battery has only been validated in English.
Interventions
DRUGSildenafil
1 capsule Sildenafil 50mg or Sildenafil 100mg or placebo taken at the time of study visit.
Sponsors
Massachusetts General Hospital
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
1. Diagnosis of schizophrenia, any subtype. 2. Age 18-65 years 3. Male or female 4. Clinically stable without a medication change within 4 weeks 5. Able to complete cognitive testing (must be English-speaking) 6. Willing to use appropriate birth control during study participation (if female)
Exclusion criteria
1. Active substance abuse or dependence 2. PDE 5 inhibitor taken within 24 hours of study drug 3. Currently taking a drug that inhibits hepatic cytochrome P450 3A4 (eg. Nefazadone, fluvoxamine, erythromycin, ketoconazole, itraconazole, cimetidine, saquinavir, ritonavir, St. John's wort, or grapefruit juice). 4. Currently taking drugs that induce P45 3A4 (eg. phenytoin, carbamezapine, Phenobarbital, rifampin) 5. Unstable medical disease 6. Significant cardiac disease 7. Bleeding disorder 8. Peptic ulcer disease 9. Hepatic impairment 10. Moderate or greater renal impairment 11. History of migraines 12. Currently taking nitrates or alpha blockers 13. Resting blood pressure \< 90/50 or \>140/90 mm. 14. History of intolerance to PDE5 inhibitors 15. History of inappropriate sexual behavior (eg, masturbation in public, stalking, assault) 16. History of priapism 17. Pregnant or lactating
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Evaluate the effects of single doses of sildenafil 50 & 100 mg compared to placebo on cognitive functioning, including verbal memory, fluency, attention, spatial memory, motor speed, and executive function. | 12 days |
Secondary
| Measure | Time frame |
|---|---|
| Evaluate the effects of single doses of sildenafil 50 & 100 mg compared to placebo on psychotic, negative, and mood symptoms. | 12 days |
| Side effects of sildenafil 50 & 100 mg as self-reported by subjects and as measured with vital signs. | 12 days |
Countries
United States
Outcome results
None listed