Artificial tears. Although not drugs per se, artificial tears provide a moist barrier to your own rapidly evaporating tears, thus stopping the endless cycle of dryness followed by reflex tearing etc.
Artificial tears. It may seem counterintuitive, but watery eyes are often caused by dry eyes. If the tears you make do not have the right components, they will not stick to the eye. You may produce a lot of tears but they roll right off the eye, sending a signal for more tears to be made. Artificial tears stick to the eye and decrease the over-production of tears. Allergies may also cause this so ask your doctor.