Which drug is NOT part of the VIVA combination associated with NAION?

The drug that is not part of the VIVA combination associated with Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) is Aspirin. The VIVA combination generally refers to the use of Viagra (sildenafil), Immitrex (sumatriptan), and Vardenafil, which are all medications known to potentially cause or be related to episodes of NAION due to their effects on blood flow and pressure in the ocular area.

Aspirin, on the other hand, is an anti-inflammatory medication primarily used for pain relief and its antiplatelet effects to prevent blood clots. It is not part of the VIVA combination and does not share the same pharmacological effects or associations with NAION as the other three drugs. Therefore, recognizing Aspirin as not being included in this context highlights its distinct role and action compared to the others that are involved in the VIVA combination.