Legal status and availability to law enforcement and emergency personnel
In the United States, naloxone is ostensibly available without a prescription in every state with the exception of Hawaii. In reality, not all pharmacies stock or dispense naloxone. Depending on the pharmacy, a pharmacist may have to write a prescription or not be able to give naloxone to comply with accounting rules, as naloxone is still considered a prescription-only medication under FDA rules. As of mid-2019, officials in 29 states had issued standing orders to enable licensed pharmacists to provide naloxone to patients without the individual first visiting a prescriber. Prescribers working with harm reduction or low threshold treatment programs  have also issued standing orders to enable these organizations to distribute naloxone to their clients. A standing order, also referred to as a "non-patient specific prescription" is written by a physician, nurse or other prescriber to authorize medicine distribution outside the doctor-patient relationship. In the case of naloxone, these orders are meant to facilitate naloxone distribution to people using opioids, family members and friends. Over 200 naloxone distribution programs utilize licensed prescribers to distribute the drug through such orders, or through the authority of pharmacists (as with Californias legal proision, AB1535).Laws and policies in many US jurisdictions have been changed in recent years to allow wider distribution of naloxone. In addition to laws or regulations permitting distribution of medicine to at risk individuals and families, some 36 states have passed laws that provide naloxone prescribers with immunity against both civil and criminal liabilities.
The S1 subpocket determines the major component of selectivity and binding. The S2 sub-pocket is small, shallow and not well defined. It merges with the S4 subpocket. The S3 sub-pocket is located on the rim of the S1 pocket and is quite exposed to solvent. The S4 sub-pocket has three ligand binding domains: the "hydrophobic box", the "cationic hole" and the water site. Factor Xa inhibitors generally bind in an L-shaped conformation, where one group of the ligand occupies the anionic S1 pocket lined by residues Asp189, Ser195, and Tyr228, and another group of the ligand occupies the aromatic S4 pocket lined by residues Tyr99, Phe174, and Trp215. Typically, a fairly rigid linker group bridges these two interaction sites. Genetics
The human factor X gene is located on chromosome 13 (13q34). Role in disease
Inborn deficiency of factor X is very rare (1:1,000,000), and may present with epistaxis (nosebleeds), hemarthrosis (bleeding into joints) and gastrointestinal blood loss. Apart from congenital deficiency, low factor X levels may occur occasionally in a number of disease states. For example, factor X deficiency may be seen in amyloidosis, where factor X is adsorbed to the amyloid fibrils in the vasculature. Deficiency of vitamin K or antagonism by warfarin (or similar medication) leads to the production of an inactive factor X. In warfarin therapy, this is desirable to prevent thrombosis. As of late 2007, four out of five emerging anti-coagulation therapeutics targeted this enzyme.Inhibiting Factor Xa would offer an alternate method for anticoagulation. Direct Xa inhibitors are popular anticoagulants.