This single-center, Phase 2, single-blind, 4-period sequential study will obtain a preliminary assessment of the effects of Ergoloid mesylates (EM) 1 mg TID and 5-hydroxytryptophan (5-HTP) 100 mg TID and the combination compared to a placebo period in males aged 18-45 years old with Fragile X Syndrome. The study will consist of a Screening period of up to 28 days prior to initial study drug administration, followed by four 4 week single-blind treatment periods (up to 21 weeks total). The screening and baseline visits may occur at the same time, provided the results of safety labs can be obtained. A final follow-up visit or phone contact for safety is planned one week after the conclusion of Period 4. Safety and tolerability assessments will include adverse event monitoring, vital signs, blood chemistry and hematology, and urinalysis. Brief cognitive and behavioral assessments will be performed during each clinic visit.~Eligible participants will progress through each of 4 periods (arms) on study. The periods are not listed sequentially here in order to preserve the single blind for participants. Throughout all 4 periods, participants will take two identical capsules three times a day. If only taking one over-encapsulated drug, they will take one over-encapsulated placebo pill with the drug at each dose, and when in period 4 they will take two over-encapsulated placebo pills at each dose.
A preliminary assessment of the safety, tolerability and efficacy of Ergoloid mesylates (EM) and 5-hydroxytryptophan (5-HTP) and the combination (EM + 5-HTP) compared to placebo in males aged 18-45 years old with Fragile X Syndrome.