Drug Name Zanaflex

Tolerance. With repeated administration of opioids, their CNS effects can lose intensity (increased tolerance). In the course of therapy, progressively larger doses are needed to achieve the same degree of pain relief.
Agents active against blood schizonts do not prevent the (symptom-free) hepatic infection, only the disease-causing infection of erythrocytes (“suppression therapy”). On return from an endemic malaria region, a 2 wk course of primaquine is adequate for eradication of the late hepatic stages (P. vivax and P. ovale).

 

Permeability to drugs of the capillary wall is determined by the structural and functional characteristics of the endothelial cells. In many capillary beds, e.g., those of cardiac muscle, endothelial cells are characterized by pronounced endo- and transcytotic activity, as evidenced by numerous invaginations and vesicles (arrows in the EM micrograph, top right).
Augmented drug extrusion: increased synthesis of the P-glycoprotein that extrudes drugs from the cell (e. g. , anthracyclines, vinca alkaloids, epipodophyllotoxins, and paclitaxel) is reponsible for multi-drug resistance (mdr-1 gene amplification). Diminished bioactivation of a prodrug, e. g. , cytarabine, which requires intracellular phosphorylation to become cytotoxic.