Ver el código de «Antibiotic Adjuvant»

= Antibiotic Adjuvants =

Antibiotic adjuvants are pharmacological agents administered alongside antibiotics to enhance their efficacy. They function either by altering the pharmacokinetics (PK) of the antibiotic to boost plasma levels or by inhibiting bacterial resistance mechanisms (Pharmacodynamics/PD).

== Pharmacokinetic Enhancers ==

These agents block the metabolism or excretion of antibiotics, maintaining higher serum concentrations for longer durations.

{| class="wikitable"
! Agent !! Mechanism !! EM Clinical Utility
|-
| '''[[Probenecid]]'''
| '''OAT Inhibition:''' Inhibits organic anion transporters (OAT1 and OAT3) in the proximal renal tubule. This competitively blocks the renal tubular secretion of organic acids, specifically [[beta-lactams]] (penicillins/cephalosporins), prolonging their half-life.<ref name="Cunningham1981">Cunningham RF, Brouhard BH, Travis LB. Clinical pharmacokinetics of probenecid. ''Clin Pharmacokinet''. 1981;6(2):135-51. [https://pubmed.ncbi.nlm.nih.gov/7011657/ PubMed Abstract]</ref>
|
* '''[[Gonorrhea]]:''' Historically used as a 1g oral single dose adjunct with [[Penicillin]] or [[Amoxicillin]] to maintain bactericidal levels longer.<ref name="CDC2021">Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. ''MMWR Recomm Rep''. 2021;70(4):1-187. [https://pubmed.ncbi.nlm.nih.gov/34292926/ PubMed Abstract]</ref>
* '''[[Neurosyphilis]]:''' Boosts CSF penetration of penicillin in outpatient/procaine regimens where IV access is difficult.<ref name="Marra2000">Marra CM, Boutin P, McArthur JC, et al. A pilot study evaluating ceftriaxone and penicillin G as treatment agents for neurosyphilis in human immunodeficiency virus-infected individuals. ''Clin Infect Dis''. 2000;30(3):540-4. [https://pubmed.ncbi.nlm.nih.gov/10722441/ PubMed Abstract]</ref>
* '''Serum Boost:''' Increases antibiotic trough concentrations by >200% for severe infections (e.g., endocarditis) or prevention of rapid elimination.<ref name="Cunningham1981" />
|-
| '''Cilastatin'''
| '''Dehydropeptidase Inhibition:''' Inhibits renal dehydropeptidase I, an enzyme found in the renal brush border that degrades [[Imipenem]]; it has no intrinsic antibacterial activity.<ref name="Birnbaum1985">Birnbaum J, Kahan FM, Kropp H, MacDonald JS. Carbapenems, a new class of antibiotics. Discovery and development of imipenem/cilastatin. ''Am J Med''. 1985;78(6A):3-21. [https://pubmed.ncbi.nlm.nih.gov/3859213/ PubMed Abstract]</ref>
| 
* '''Nephroprotection:''' Prevents the formulation of nephrotoxic metabolites of Imipenem formed during renal metabolism.
* '''Mandatory Co-administration:''' Always formulated as Imipenem/Cilastatin (Primaxin).<ref name="Birnbaum1985" />
|}

=== Probenecid Specifics ===
; Dosing
* '''Standard Adjuvant:''' 500 mg PO QID.
* '''Gonorrhea protocol:''' 1 g PO single dose associated with oral beta-lactams.
; Contraindications
* '''Renal Failure:''' Ineffective if CrCl < 30 mL/min (drug cannot reach site of action in the tubule).<ref name="Cunningham1981" />
* '''Pediatrics:''' Generally contraindicated in children < 2 years old due to immature renal transport systems.
* '''Acute Gout:''' Paradoxically, do not initiate during an acute [[Gout|gouty flare]] (mobilization of urate stores can exacerbate symptoms), despite it being a gout medication.
; Interactions
* Significantly increases toxicity of [[Methotrexate]] and [[NSAIDs]] via the same OAT inhibition pathway.<ref name="Kyriazis2013">Kyriazis AP, Kyriazis MA, Burke MD. Interaction of antibiotics with the renal organic anion and cation transporters. ''Expert Opin Drug Metab Toxicol''. 2013;9(2):163-7. [https://pubmed.ncbi.nlm.nih.gov/23199343/ PubMed Abstract]</ref>

== Beta-Lactamase Inhibitors ==

While technically distinct chemical structures, these "suicide inhibitors" generally have negligible antibacterial activity alone and are used strictly as adjuvants to overcome enzymatic resistance.

{| class="wikitable"
! Agent !! Combined With !! EM Clinical Utility
|-
| '''Clavulanate'''
| [[Amoxicillin]] (Augmentin) || Oral coverage for polymicrobial infections (e.g., [[Dog bite|animal bites]], [[Sinusitis]], mild [[Diverticulitis]]). Extends spectrum against S. aureus (MSSA), H. influenzae, and Bacteroides.<ref name="Drawz2010">Drawz SM, Bonomo RA. Three decades of beta-lactamase inhibitors. ''Clin Microbiol Rev''. 2010;23(1):160-201. [https://pubmed.ncbi.nlm.nih.gov/20065329/ PubMed Abstract]</ref>
|-
| '''Sulbactam'''
| [[Ampicillin]] (Unasyn) || IV coverage for [[Aspiration pneumonia and pneumonitis]] and intra-abdominal sepsis. *Uniquely has intrinsic activity against [[Acinetobacter]] on its own.*<ref name="Levin2003">Levin AS, Levy CE, Manrique AE, Medeiros EA, Costa SF. Severe nosocomial infections with imipenem-resistant Acinetobacter baumannii treated with ampicillin/sulbactam. ''Int J Antimicrob Agents''. 2003;21(1):58-62. [https://pubmed.ncbi.nlm.nih.gov/12507840/ PubMed Abstract]</ref>
|-
| '''Tazobactam'''
| [[Piperacillin]] (Zosyn) || Broad-spectrum agent for [[Sepsis]], [[Pseudomonas]], and nosocomial infections in the ED. Chemically a penicillanic acid sulfone.<ref name="Drawz2010" />
|-
| '''Avibactam'''
| [[Ceftazidime]] (Avycaz) || Non-beta-lactam scaffold inhibitor. Reserved for [[CRE|Carbapenem-Resistant Enterobacteriaceae]] (CRE) or MDR Pseudomonas. Consult ID before use.<ref name="VanDuin2016">van Duin D, Bonomo RA. Ceftazidime/Avibactam and Ceftolozane/Tazobactam: Second-generation β-Lactam/β-Lactamase Inhibitor Combinations. ''Clin Infect Dis''. 2016;63(2):234-41. [https://pubmed.ncbi.nlm.nih.gov/27098166/ PubMed Abstract]</ref>
|}

== Synergistic Adjuvants ==

Agents used to attack a bacteria from a second angle (mechanism of action) to clear difficult infections.

* '''[[Aminoglycosides]] (e.g., Gentamicin):'''
** Used as an adjuvant with Ampicillin or Vancomycin for [[Endocarditis]].
** ''Mechanism:'' Cell wall synthesis inhibitors (beta-lactams) allow the aminoglycoside to penetrate the cell wall and disrupt protein synthesis (ribosomal lethal effect).<ref name="Davis1987">Davis BD. Mechanism of bactericidal action of aminoglycosides. ''Microbiol Rev''. 1987;51(3):341-50. [https://pubmed.ncbi.nlm.nih.gov/3312985/ PubMed Abstract]</ref>
* '''[[Rifampin]]:'''
** Used as an adjuvant for Prosthetic joint infections.
** ''Mechanism:'' Able to penetrate adherence biofilms on hardware that other antibiotics cannot reach; acts on RNA polymerase.<ref name="Zimmerli2004">Zimmerli W, Trampuz A, Ochsner PE. Prosthetic-joint infections. ''N Engl J Med''. 2004;351(16):1645-54. [https://pubmed.ncbi.nlm.nih.gov/15483283/ PubMed Abstract]</ref>

== References ==
{{Reflist|2}}

[[Category:Pharmacology]] [[Category:ID]]