Theobromine - snorting a vasodilator with a tryptamine may enhance absorption. This could be done sub lingual or nasally. It is likely that a small amount would have an effect. It could also be combined with an MAOI. There may be a faster onset and enhanced effect if greater bioavailability and absorption occurs.
ANY SWIM's out there looking for something to do?

Enhancement occurs because the dilation of the blood vassals near the point of contact is increased by the theobromine. This dilation allows more drug to be absorbed into the blood.

Exactly. This may have application with a variety of drugs. I thought of it in pharmacology class the other day when we learned that vasoconstrictors are administered with local anesthetics to slow absorption into the blood and thus would lead to a decrease in the local concentration. With a vasodilator co-administered not only should more be absorbed into the blood because of great surface area and plasma volume(dilation) but also the blood flow will be greater (less resistance) this will aid to enhance the equilibrium across the membrane by washing the absorbed drug away thus pushing the equilibrium towards greater absorption. If blood flow is slower the drug is not washed away as much and equilibrium is reached.

When formulating a sublingual medicine, it’s beneficial to add additional acid. This causes the blood vessels in the mouth to dilate which helps absorption. Unfortunately, some drugs absorb poorly in a low pH environment, so this has limited application.

Calcium hydroxide is often used to help drugs absorb sublingually or intranasally. Calcium hydroxide causes lesions. These lesions allow the drugs to enter into the blood stream more easily. It also controls the pH keeping it high, which is beneficial for a lot of drugs.

A mix of calcium hydroxide and theobromine should produce a very good rate of absorption for nasal drug use. The theobromine would dilate the blood vessels, the calcium hydroxide would cause lesions and bring the pH up really high allowing many drugs to pass through as freebase compounds. (Note that some drugs require a low pH in order to pass through as freebase, but alkaloids like DMT, bufotenine, etc., require a hi pH).

Drugs absorb best as the un-ionized forms. Therefore with basic drugs the freebase absorbs best (high pH), whereas with weak acids you would want a low pH so that equilibrium favors the unionizd form.