Your goal is to extract structured information from the user's input that matches the form described below. When extracting information please make sure it matches the type information exactly. Do not add any attributes that do not appear in the schema shown below.

```TypeScript

 { // Information on the clinical trial characteristics from the abstract
 conditions: string // The condition or disease being treated in the clinical trial
 drug_or_intervention: string // The drug or intervention used in the clinical trial
}
```


Please output the extracted information in JSON format. Do not output anything except for the extracted information. Do not add any clarifying information. Do not add any fields that are not in the schema. If the text contains attributes that do not appear in the schema, please ignore them. All output must be in JSON format and follow the schema specified above. Wrap the JSON in <json> tags.



Input:Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication.  Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication. This randomized double-blind placebo-controlled crossover study included 88 patients recruited by surgeons from outpatient clinics. The participants abstained from caffeine for 48 h before each test and then received either a placebo or oral caffeine (6 mg/kg). After 75 min, pain-free and maximal walking distance on a treadmill, perceived pain, reaction times, postural stability, maximal isometric knee extension strength, submaximal knee extension endurance and cognitive function were measured. The analysis was by intention to treat. Caffeine increased the pain-free walking distance by 20.0 (95 per cent confidence interval 3.7 to 38.8) per cent (P = 0.014), maximal walking distance by 26.6 (12.1 to 43.0) per cent (P < 0.001), muscle strength by 9.8 (3.0 to 17.0) per cent (P = 0.005) and endurance by 21.4 (1.2 to 45.7) per cent (P = 0.004). However, postural stability was reduced significantly, by 22.1 (11.7 to 33.4) per cent with eyes open (P < 0.001) and by 21.8 (7.6 to 37.8) per cent with eyes closed (P = 0.002). Neither reaction time nor cognition was affected. In patients with moderate intermittent claudication, caffeine increased walking distance, maximal strength and endurance, but affected balance adversely. Output:
{'conditions': 'Intermittent Claudication', 'interventions': 'Drug: Caffeine 6mg/kg'}