Medications might also cause a drop in blood pressure. Beta-blockers and nitroglycerin, used to treat heart disease, are common culprits. Diuretics, tricyclic antidepressants, and erectile dysfunction drugs can also cause hypotension. Some people have low blood pressure for unknown reasons.
Theoretically, then, the President can probably pardon him/her-self for any Federal crime â but this only prevents actual prosecution for that crime, not impeachment for the crime itself. Prior Answer, to the hypothetical of the VP murdering the President and then pardoning himself:
Constitutional Authority for Presidential Pardons. The power to grant pardons is given to the President of the United States by Article II, Section 2 of the U.S. Constitution, which states in part: The President ... shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment..