The use of the immediate-release nifedipine is con- traindicated in patients with STEMI because of hypotension and reflex sympathetic activation with tachycardia.446 Few data exist to support or refute the value of the routine use of oxygen in the acute phase of STEMI, and more research is needed. A pooled Cochrane analysis of 3 trials showed a 3-fold higher risk of death for patients with confirmed acute MI treated with oxygen than for patients with acute MI man- aged on room air. Oxygen therapy is appropriate for patients who are hypoxemic (oxygen saturation <90%) and may have a salutary placebo effect in others. Supplementary oxygen may, however, increase coronary vascular resistance.447 Oxy- gen should be administered with caution to patients with chronic obstructive pulmonary disease and carbon dioxide retention. 8.7. Analgesics: Morphine, Nonsteroidal Anti- Inflammatory Drugs, and Cyclooxygenase II Inhibitors In the absence of a history of hypersensitivity, morphine sulfate is the drug of choice for pain relief in patients with STEMI, especially those whose course is complicated by acute pulmonary edema. It can alleviate the work of breath- ing, reduce anxiety, and favorably affect ventricular loading conditions. The dose of morphine sulfate needed to achieve adequate pain control will vary depending on patient age, body size, BP, and heart rate. Naloxone can be administered in doses of 0.1 to 0.2 mg IV every 15 minutes when indicated to reverse the narcotic effects of morphine, and atropine 0.5 to 1.5 mg IV may be administered to counter excessive mor- phine-related bradycardia. 