A patient is hospitalized with a central nervous system infection that needs to be treated with water-soluble antibiotics.The medications will be instilled into the subarachnoid space via an epidural catheter.Why is this the best route of administration for this patient?

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Quizplus · Accepted Answer

To be distributed to an organ,a medication needs to pass through all the biological membranes of that organ.Some membranes serve as barriers to the passage of medications.For example,the blood-brain barrier allows only lipid-soluble medications to pass into the brain and cerebrospinal fluid.Therefore central nervous system (CNS)infections sometimes require treatment with antibiotics injected directly into the subarachnoid space in the spinal cord.Older patients often experience adverse effects (e.g.,confusion)because they experience a change in the permeability of the blood-brain barrier,which enhances the passage of fat-soluble medications into the brain.Lipid-soluble,nonionized drugs easily cross the placenta and can cause serious harm to the fetus.

A Patient Is Hospitalized with a Central Nervous System Infection