Do you have access to epocrates or other subscription based pages? If not then you will have to settle for ivermectin's wikipedia page If you have access to the subscription services then wikipedia has them linked for you to review.

quote:
Ivermectin can be given by mouth, topically, or via injection. It does not readily cross the blood–brain barrier of mammals due to the presence of P-glycoprotein (the MDR1 gene mutation affects function of this protein). Crossing may still become significant if ivermectin is given at high doses (in which case, brain levels peak 2–5 hours after administration).

Ivermectin does not cross the BBB when used at approved dosages. However it does cross at higher than approved dosages.

quote:
One main concern is neurotoxicity after large doses, which in most mammalian species may manifest as central nervous system depression, ataxia, coma, and even death,

quote:
Since drugs that inhibit the enzyme CYP3A4 often also inhibit P-glycoprotein transport, the risk of increased absorption past the blood-brain barrier exists when ivermectin is administered along with other CYP3A4 inhibitors. These drugs include statins, HIV protease inhibitors, many calcium channel blockers, lidocaine, the benzodiazepines, and glucocorticoids such as dexamethasone.

Let me translate that for you, glucocorticoids inhibit CY3PA => increased ivermectin concentration => increased risk of ivermectin (a neurotoxic agent) crossing the BBB at any dose but especially high dosages.

quote:
In vitro, ivermectin has antiviral effects against several distinct positive-sense single-strand RNA viruses, including SARS-CoV-2. Subsequent studies found that ivermectin could inhibit replication of SARS-CoV-2 in monkey kidney cell culture with an IC50 of 2.2–2.8 µM.Based on this information, however, doses much higher than the maximum approved or safely achievable for use in humans would be required for an antiviral effect

So to achieve an antiviral effect dosages much higher than the maximum safe dosage would be needed. Add that to the fact that glucocorticoids increase the serum concentration because they inhibit the enzyme that is vital in eliminating ivermectin. You get a serum concentration of ivermectin that is not only a risk for crossing the BBB but almost certainly going to cross the BBB which again is no bueno.

This post was edited on 7/21/21 at 12:06 pm