When a benign brain tumor causes increased intracranial pressure, would doxycycline further increase the pressure?

Doxycycline is not commonly used to decrease intracranial pressure or known to have this effect. Moreover, there have been described cases of tetracyclines as doxycycline increasing intracranial pressure. Would suggest discussing above concerns with prescribing physician.

If a brain tumor, benign or not, is large enough to create a mass effect resulting in increased intracranial pressure, doxycycline would have a trivial effect at most, and would be the least of the problem.