"i have asthma and am in and out of the hospital often with bronchitis and pleurisy. which if you don&#039;t know, pleurisy can be extremely painful. my doctor orders 4 mg dilaudid with 75 mg phenergan iv every 4 hours as needed and it works almost immediately. it&#039;s about the only thing that gives me relief when the pleurisy gets to the point of hospitalization."