<p>Intravenous&nbsp;injections of Protamine sulfate may cause a sudden fall in&nbsp;blood pressure, bradycardia, pulmonary hypertension,&nbsp;dyspnea, or transitory flushing and a feeling of warmth. There have been reports of&nbsp;anaphylaxis&nbsp;that resulted in respiratory embarrassment. Other reported adverse reactions include systemic hypertension, nausea, vomiting and lassitude.&nbsp;Back pain&nbsp;has been reported rarely in conscious patients undergoing such procedures as&nbsp;cardiaccatheterization. Because fatal reactions often resembling anaphylaxis have been reported after administration of Protamine sulfate, the drug should be given only when&nbsp;resuscitation&nbsp;techniques and treatment of anaphylactoid shock&nbsp;are readily available.</p>