<s>[INST] context: Ref. GG I2!h edp.799 Explanation: Direct Renin Inhibitor DRIs are a novel class of antihypertensive drugs that inhibit the RAS at its origin. Angiotensinogen is the only specific substrate for renin, and its conversion to AngI presents a rate-limiting step for the generation of downstream components of the RAS. Aliskiren is a low-molecular-weight non-peptide that is a potent competitive inhibitor of renin. It binds the active site of renin to blocks the conversion of angiotensinogen to Ang I, thus reducing the consequent production of Ang II. Aliskiren has a 10.000-fold higher affinity to renin than to any other aspartic peptidases. The till is 20-45 hours. Plasma protein binding is 50% and is independent of concentration. Aliskiren is a substrate for P-glycoprotein (Pgp). which accounts for low absorption. Adverse Events- diarrhea, nasopharyngitis, cough (cough was much less common than with ACE inhibitors), elevated uric acid, renal stones, and gout. Like other RAS inhibitors, aliskiren is not recommended in pregnancy. Aliskiren reduces absorption of furosemide by 50%. Note: Vernakalant is an investigational multi-channel blocker that was developed for the treatment of atrial fibrillation. Adverse effects of vernakalant include dysgeusia (disturbance of taste), sneezing, paresthesia, cough, and hypotension. [/INST] question: Which of the following is a direct renin inhibitor? | options: A: Aliskrein B: Losartan C: Perindopril D: Vernakalant | answer: A </s>