The purpose of this study is to assess the benefit to patients with empyema or complicated parapneumonic effusion (CPE) using a daily versus twice daily Alteplase regimen of two different dose strategies compared with saline placebo.

This is a randomized, double-blind, placebo-controlled pilot study. Patients with empyema and complicated parapneumonic effusion who are felt to require fibrinolytic therapy will be considered for study enrollment. Enrolled patients will be randomized to one of five potential treatment arms (saline placebo, 4 mg once daily, 4 mg twice daily, 10 mg once daily, or 10 mg twice daily) in a double-blinded manner.

Inclusion Criteria:

• Ability to provide written informed consent
• Age greater or equal to 18 yrs
• Presence of empyema or CPE

Exclusion Criteria:

• Active internal bleeding
• Pregnancy
• Prior enrollment in this study
• Platelet count less than 100,000/mm3
• Use of warfarin sodium if INR is greater than 1.7
• Use of heparin unless the PTT is less than 1.5 times baseline normal
• Known neurological disorders
• Current or pre-existing bleeding dyscrasia
• Known allergy to Alteplase