Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Randomized, Double Blind, Placebo Controlled Study to Investigate the Effect of Donepezil and Gabapentin Combination on an Experimental Pain Model in Healthy Subjects
Brief Summary: This study will compare the effects of gabapentin alone, and gabapentin + donepezil given together in two types of experimental electrical pain tests in up to 48 healthy male subjects (after 24 recruited in the first cohort an interim analysis will be performed).

The study is a randomized, double blind, placebo controlled, 3 was cross-over design study with incomplete block design and 4 treatment options. Placebo, gabapentin alone (lower dose and higher dose) or gabapentin (lower dose) with donepezil.


Options:
A: Inclusion Criteria:

* Patients must meet the ACR criteria for fibromyalgia (ie, widespread pain present for at least 3 months, and pain in at least 11 of 18 specific tender point sites.
* Patients must have a score of \>40 mm on the Visual Analog Scale

Exclusion Criteria:

* Patients with any widespread inflammatory musculoskeletal disorders, widespread rheumatic diseases other than fibromyalgia, active infections, or untreated endocrine disorders.
B: Inclusion Criteria:

1. Male between 18 and 55 years of age inclusive, at the time of signing the informed consent.
2. Body weight ≥ 50 Kilogram (kg) and BMI within the range 18.5-29.9 Killogram per square meter (kg/m2) (inclusive).
3. Healthy as determined by a responsible and experienced physician, based on a medical evaluation including medical history, physical examination, psychiatric history, psychiatric evaluation, laboratory tests and cardiac monitoring.
4. Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), alkaline phosphatase and bilirubin ≤ 1.5x Upper Limit of Normal (ULN)
5. QT duration corrected for heart rate by Bazett's formula (QTcB) or QT duration corrected for heart rate by Fridericia's formula (QTcF) \< 450 milli second (msec).

Exclusion Criteria:

1. The subject has either a previous disease or current medical condition, which as judged by the Investigator, may compromise safety or affect the interpretation of efficacy data.
2. History of known or suspected seizures, including infantile febrile, unexplained significant and recent loss of consciousness or history of significant head trauma with loss of consciousness or a family history (first degree relative) of epilepsy or seizures (fits).
3. Abnormalities in 12-lead Electrocardiogram (ECG)
4. Systolic blood pressure (BP) below 90 or above 160mm Hg, or diastolic blood pressure below 50 or above 100 millimeters of mercury (mmHg).
5. History of sensitivity to any of the study medications
6. History of regular alcohol consumption within 6 months of the study defined as: an average weekly intake of \>21 units. One unit is equivalent to 8 g of alcohol: a half-pint (\~240 millil litre \[ml\]) of beer, 1 glass (125 ml) of wine or 1 (25 ml) measure of spirits.
7. A positive pre-study drug/alcohol screen at the screening visit.
8. Excessive caffeine drinkers (\~5 or more cups a day) .
9. Excessive smokers (\>5 /day)
10. Use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to screening, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety.
11. Use of any topical steroid or capsaicin preparations in the previous 30 days to screening, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety.
12. The subject is needle phobic
13. The subject is unable to tolerate the electrical hyperalgesia model or nerve stimulation, including anxiety or atypical response to the stimulation on the training at the screening visit.
14. The subject does not produce an area of allodynia or hyperalgesia to the electrical hyperalgesia model during the screening session.
15. Subject who, in the investigator/designee's judgement, poses a significant suicide risk. Evidence of serious suicide risk may include any history of suicidal behaviour and/or any evidence of suicidal ideation on any questionnaires e.g. type 4 or 5 on the C-SSRS in the last 6 months.
16. The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the baseline session in the current study: 90 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer).
17. Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 84 day period.
18. A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening
19. Unwillingness or inability to follow the procedures outlined in the protocol.
C: Inclusion Criteria:

* Patients who met the American College of Rheumatology (ACR) criteria for fibromyalgia (ie, widespread pain present for at least 3 months, and pain in at least 11 of 18 specific tender point sites)
* Patients who completed at least 4 pain diaries within the last 7 days and the average pain score must have been ≥4, and had a score of ≥40 mm on the Visual Analogue Scale (VAS) of the SF-MPQ at screening (Visit 1) and randomization (Visit 2)

Exclusion Criteria:

* Patients with other severe pain that may confound assessment or self-evaluation of the pain associated with fibromyalgia
* Patients with any inflammatory muscle or rheumatologic disease other than fibromyalgia, active infections, or untreated endocrine disorders
* Patients with severe depression
D: Inclusion Criteria:

* ACR criteria for fibromyalgia
* A score of more or equal to 40 mm on the Pain Visual Analog Scale (VAS) and a an average score more or equal to 4 on 4 daily pain diaries

Exclusion Criteria:

* Patients with other severe pain conditions
* Patients with severe depression
* Patients taking excluded medications

Answer: B