4 ms·
What makes you sleepy is that the drugs cross the blood-brain barrier. Newer drugs containing fexofenadine do not have that side effect.
by 0x45696e6172 8y ago
What makes you sleepy is that the drugs cross the blood-brain barrier. Newer drugs containing fexofenadine do not have that side effect.
- maxerickson 8y agoCetirizine is also a newer drug and is not supposed to cross the blood-brain barrier as much.