Post-exposure prophylactic

Cethromycin (ABT-773) 39 (Advanced Life Sciences) had an NDA filed in October 2008 for the treatment of CAP.67 Advanced Life Sciences is also evaluating cethromycin 39 against other respiratory tract infections and in pre-clinical studies as a prophylactic treatment of anthrax post-exposure. Cethromycin 3968 70 is a semi-synthetic ketolide derivative of erythromycin 4071 originally synthesised by Abbott Laboratories,72 which like erythromycin 40, inhibits bacterial protein synthesis through binding to the peptidyl-transferase site of the bacterial 50S ribosomal subunit. Important macrolide antibiotics in clinical use today include erythromycin 40 itself, clarithromycin, azithromycin and, most recently, telithromycin (launched in 2001). 

FIGURE 63.2. Experimental design for demonstration of how insufficient prophylactic treatment can be compensated for by adjunct post-exposure treatment. Low dose of scopolamine requires additional treatment (A). High dose of scopolamine is sufficient to terminate seizures (B). High dose of scopolamine given outside the cholinergic window requires additional treatment (C). 

It appears from these results that simple prophylaxis (without post-exposure treatment) against OP is not sufficient. Therefore, pyridostigmine has importance as a prophylactic drug especially when it is combined with post-exposure antidotal treatment. For further development, it is necessary to search for novel prophylactic drugs and new routes of administration. In this context, preparations of cholinesterases are of special importance for the development of more effective prophylactics. 

Passive immnnization of the recipient at the time of potential exposnre to hepatitis B virus is available. Prophylactic or post-exposure administration of hepatitis B immnnoglobnlin (HBIG) is of value in the prevention of hepatitis B. Addition of anti-hepatitis-B immunoglobulin to factor concentrates appears to abolish hepatitis B virus infectivity (160,161). Hepatitis B immunization has been used effectively in controlled trials (162,163). The prophylactic effectiveness of the vaccine administered immediately after exposure to hepatitis B virus has not been established (164). 

The use of any drug, even as a prophylactic measure, may be associated with adverse effects. Adverse effects of antiretroviral medications are well-described in the HIV population however, there is sparse data about adverse effects in the non-HIV-infected individuals. Between October of 1996 and December of 1998, an HIV post-exposure prophylaxis registry prospectively followed... 

Exposure of skin to chemical warfare agents can be reduced by the use of barrier creams, decontaminants or by removal of superficially absorbed chemicals ( catch-up therapies ). In short, prophylactic barrier creams seek to prevent skin contact whereas decontaminants and catch-up therapies are post-exposure measures that can only minimise skin absorption. Barrier creams may also be applied to skin under PPE to enhance protection at vulnerable areas, such as the groin and axillae. 

The term prophylaxis as used in this chapter is limited to medical countermeasures applied relatively shortly before penetration of a toxic agent into the organism. There is a question what will happen after the administration of the prophylactic drug. When the treatment is unnecessary, it can be described as prophylaxis. However, though successful prophylaxis can be observed for some OP, full protection of the organism without post-exposure treatment, especially for soman poisoning, remains open. When the treatment is involved after exposure, the term pre-treatment has become to be accepted. 

Conventionally, NA poisoning is treated by a combi-nahon of prophylactic and post-exposure therapy, which target the three post-exposure phases of neurotransmitter systems described. Prophylactic treatments are designed to circumvent aging of e NA-AChE complex and consist of carbamate anticholinesterases (e.g., pyridostigmine)... 

Another important difference between the military and civilian sectors is that military officials may be able to predict with some degree of certainty when CWAs could be used, and thus equip the warfighter with pre-and post-exposure coxmtermeasures, such as PB and Duodote kits. However, since it is nearly impossible to predict when a civilian attack may occur, the NIH has been primarily focused on treating victims after exposure to CWAs. The exception to this approach is that there is some current research into prophylactic treatments that could be administered to first-responders who must enter a contaminated site or those who must treat victims that may still be contaminated, such as healthcare providers in the emergency department. 

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