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Tissue concentrations of harmine fall to a very low level 1 hour after injection while "those of harmaline decline progressively over a period of several hours."

After intravenous administration into mice the uptake into the brain is slower for harmaline than for harmine.

(Given sc) Harmaline enters the brain within 30 minutes and peak concentrations occur at 1 hour.

The rate of elimination from the brain is slower for harmaline (half-life 53.4 minutes) than for harmine (half-life 10.1 minutes)

The duration of tremor is different.

The rate of excretion for harmine and its metabolites is faster in man (half life 3 hours) than in rats (half-life 6-7 hours) indicating distinct differences between species.

In rats:

• Harmine metabolizes to harmol sulfate while harmaline metabolizes to harmalol glucuronide. Harmalol is a poor substrate for phenosulfotransferase.
• Harmine causes an increase in 5HT concentration in the whole brain, striatum and thalamus.
• 5HT was rapidly elevated 10 minutes after injection(ip) of harmaline, maximal concentration around 200 minutes and strong MAO inhibition was present for 2-3 hours.