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:Ambrisentan therapy in patients with pulmonary arterial hypertension who discontinued bosentan or sitaxsentan due to liver function test abnormalities.  Some endothelin receptor antagonists (ERAs) are associated with liver function test (LFT) result abnormalities. However, ambrisentan has an incidence of serum aminotransferase levels more than three times the upper limit of normal (ULN), similar to that observed in PAH patients who are not receiving ERAs. Because ambrisentan may provide benefits in PAH patients who have discontinued ERA therapy due to LFT abnormalities, we evaluated the safety and efficacy of ambrisentan in this patient population. Patients who previously discontinued bosentan and/or sitaxsentan due to LFT abnormalities received ambrisentan, 2.5 mg qd, for 4 weeks followed by 5 mg/d for 8 weeks. The primary end point was the incidence of aminotransferase levels more than three times ULN considered by the investigator to be related to ambrisentan and resulting in drug discontinuation. Secondary end points included aminotransferase levels more than five times ULN requiring drug discontinuation and more than three times ULN requiring dose reduction, as well as changes in 6-min walk distance (6MWD), Borg dyspnea index, World Health Organization functional class, and Short Form-36 health survey score. Patients continued treatment beyond the 12-week end point with monthly monitoring of LFTs. Thirty-six patients who previously discontinued bosentan (n = 31), sitaxsentan (n = 2), or both (n = 3) were enrolled. At baseline, 69.4% of patients were receiving prostanoid and/or sildenafil therapy. No patient had an aminotransferase level more than three times ULN that required ambrisentan discontinuation. One patient had a transient aminotransferase level more than three times ULN that resolved following a temporary dose reduction. No additional aminotransferase levels more than three times ULN were observed with long-term treatment (median exposure, 102 weeks), despite dose increases to 10 mg qd in more than half of the patients. Significant improvements in 6MWD and other efficacy assessments were observed. Ambrisentan treatment may be an option for patients who have discontinued bosentan and/or sitaxsentan therapy due to LFT result abnormalities. Clinicaltrials.gov Identifier NCT00423592. Output:

conditions: Pulmonary Hypertension
interventions: Drug: ambrisentan