Ampicillin/sulbactam is a fixed-dose combination medication of the common

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from '' Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum usin ...

-derived

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

ampicillin Ampicillin is an antibiotic used to prevent and treat a number of bacterial infections, such as respiratory tract infections, urinary tract infections, meningitis, salmonellosis, and endocarditis. It may also be used to prevent group B str ...

and sulbactam, an

inhibitor Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

l beta-lactamase. Two different forms of the drug exist. The first, developed in 1987 and marketed in the United States under the brand name Unasyn, generic only outside the United States, is an

intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

antibiotic. The second, an oral form called sultamicillin, is marketed under the brand name Ampictam outside the United States, and generic only in the United States. Ampicillin/sulbactam is used to treat

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

s caused by bacteria resistant to beta-lactam antibiotics. Sulbactam blocks the

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

which breaks down ampicillin and thereby allows ampicillin to attack and kill the bacteria.

Medical uses

Ampicillin/sulbactam has a wide array of medical use for many different types of infectious disease. It is usually reserved as a second-line therapy in cases where bacteria have become beta-lactamase resistant, rendering traditional penicillin-derived antibiotics ineffective. It is effective against certain gram positive bacteria, gram-negative bacteria, and anaerobes.Pamphlet Pfizer. Unasyn® (ampicillin sodium/sulbactam sodium) prescribing information. New York, NY; Updated May 2014. * Gram-positive bacteria: Staphylococcus aureus (beta-lactamase and non-beta-lactamase producing), Staphylococcus epidermidis (beta-lactamase and non-beta-lactamase producing), Staphylococcus saprophyticus (beta-lactamase and non-beta-lactamase producing), Streptococcus faecalis (Enterococcus), Streptococcus pneumoniae, Streptococcus pyogenes, and Streptococcus viridans.Clinical and Laboratory Standard Institute (CLSI). Performance Standards for Antimicrobial Disk Diffusion Susceptibility Tests; Approved Standard – 11th ed. CLSI document M02-A11. CLSI, 950 West Valley Rd., Suite 2500, Wayne, PA 19087, 2012. * Gram-negative bacteria: Hemophilus influenzae (beta-lactamase and non-beta-lactamase producing), Moraxella (Branhamella) catarrhalis (beta-lactamase and non-beta-lactamase producing), Escherichia coli (beta-lactamase and non-beta-lactamase producing), Klebsiella species (all known species are beta-lactamase producing), Proteus mirabilis (beta-lactamase and non-beta-lactamase producing), Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Morganella morganii, and Neisseria gonorrhoeae (beta-lactamase and non-beta-lactamase producing). * Anaerobes: Clostridium species, Peptococcus species, Peptostreptococcus species, Bacteroides species including B. fragilis. Gynecological Infections Ampicillin/sulbactam can be used to treat gynecological infections caused by beta-lactamase producing strains of Escherichia coli, and Bacteroides (including B. fragilis).Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing; 22nd Supplement. CLSI document M100-S22, 2012.> Bone and joint infections Ampicillin/sulbactam can be used in the treatment of bone and joint infections caused by susceptible beta-lactamase producing bacteria. Intra-abdominal infections Ampicillin/sulbactam can be used to treat intra-abdominal infections caused by beta-lactamase producing strains of Escherichia coli, Klebsiella (including K. pneumonia), Bacteroides fragilis, and Enterobacter. Skin and skin structure Infections This medication can be used to treat skin and skin structure infections caused from beta-lactamase-producing strains of Staphylococcus aureus, Enterobacter, Escherichia coli, Klebsiella (including K. pneumoniae), Proteus mirabilis, Bacteroides fragilis, and Acinetobacter calcoaceticus. Examples of skin conditions treated with ampicillin-sulbactam are moderate to severe diabetic foot infections and type 1 Necrotizing fasciitis, commonly referred to as "flesh-eating bacteria".

Contraindications

Ampicillin/sulbactam is contraindicated in individuals who have a history of a penicillin allergy. Symptoms of allergic reactions may range from rash to potentially life-threatening conditions, such as anaphylaxis. Patients who have asthma, eczema, hives, or hay fever are more likely to develop undesirable reactions to any of the penicillins.Clinical Pharmacology Web site. http://www.clinicalpharmacologyip.com/Forms/Monograph/monograph.aspx?cpnum=35&sec=moncontr&t=0. Accessed November 21, 2014.

Adverse effects

Reported adverse events include both local and systemic reactions. Local adverse reactions are characterized by redness, tenderness, and soreness of the skin at the injection site. The most common local reaction is injection site pain. It has been reported to occur in 16% of patients receiving intramuscular injections, and 3% of patients receiving intravenous injections. Less frequently reported side effects include inflammation of veins (1.2%), sometimes associated with a blood clot (3%). The most commonly reported systemic reactions are diarrhea (3%) and rash (2%).UNASYN ackage insert Pifzer Inc., New York, NY; April 2007.http://labeling.pfizer.com/ShowLabeling.aspx?id=617. Accessed November 21, 2014. Less frequent systemic reactions to ampicillin/sulbactam include chest pain, fatigue, seizure, headache, painful urination, urinary retention, intestinal gas, nausea, vomiting, itching, hairy tongue, tightness in throat, reddening of the skin, nose bleeding, and facial swelling. These are reported to occur in less than 1% of patients.Unasyn. Lexi-Drugs Online. LexiComp Web Site. http://online.lexi.com/lco/action/doc/retrieve/docid/patch_f/6354#f_adverse-reactions. Accessed November 21, 2014.

Pharmacology

Pharmacodynamics and pharmacokinetics

The addition of sulbactam to ampicillin enhances the effects of ampicillin. This increases the antimicrobial activity by 4- to 32-fold when compared to ampicillin alone. Ampicillin is a time-dependent antibiotic. Its bacterial killing is largely related to the time that drug concentrations in the body remain above the minimum inhibitory concentration (MIC). The duration of exposure will thus correspond to how much bacterial killing will occur. Various studies have shown that, for maximum bacterial killing, drug concentrations must be above the MIC for 50-60% of the time for the penicillin group of antibiotics. This means that longer durations of adequate concentrations are more likely to produce therapeutic success. However, when ampicillin is given in combination with sulbactam, regrowth of bacteria has been seen when sulbactam levels fall below certain concentrations. As with many other antibiotics, under-dosing of ampicillin/sulbactam may lead to resistance. Ampicillin/sulbactam has poor absorption when given orally. The two drugs have similar pharmacokinetic profiles that appear unchanged when given together. Ampicillin and sulbactam are both hydrophilic antibiotics and have a volume of distribution (Vd) similar to the volume of extra-cellular body water. The volume that the drug distributes throughout in healthy patients is approximately 0.2 liters per kilogram of body weight. Patients on hemodialysis, elderly patients, and pediatric patients have shown a slightly increased volume of distribution. Using typical doses, ampicillin/sulbactam has been shown to reach desired levels to treat infections in the brain, lungs, and abdominal tissues. Both agents have moderate protein binding, reported at 38% for sulbactam and 28% for ampicillin.15,16 The half-life of ampicillin is approximately 1 hour, when used alone or in combination with sulbactam; therefore it will be eliminated from a healthy person in around 5 hours. It is eliminated primarily by the urinary system, with 75% excreted unchanged in the urine. Only small amounts of each drug were found to be excreted in the bile. Ampicillin/sulbactam should be given with caution in infants less than a week old and premature neonates. This is due to the underdeveloped urinary system in these patients, which can cause a significantly increased half-life for both drugs.16 Based on its elimination, ampicillin/sulbactam is typically given every 6 to 8 hours. Slowed clearance of both drugs has been seen in the elderly, renal disease patients, and critically ill patients on renal replacement therapy. Reduced clearance has been seen in both pediatric and post-operative patients. Adjustments in dosing frequency may be required in these patients due to these changes.

Mechanism of action

Ampicillin/sulbactam is a combination of a β-lactam antibiotic and a β-lactamase inhibitor. Ampicillin works by binding to penicillin-binding proteins (PBPs) to inhibit bacterial cell wall synthesis. This causes disruption of the bacterial cell wall and leads to bacterial cell death. However, resistant pathogens may produce β-lactamase enzymes that can inactivate ampicillin through hydrolysis. This is prevented by the addition of sulbactam, which binds and inhibits the β-lactamase enzymes. It is also capable of binding to the PBP of ''

Bacteroides fragilis ''Bacteroides fragilis'' is an anaerobic, Gram-negative, pleomorphic to rod-shaped bacterium. It is part of the normal microbiota of the human colon and is generally commensal, but can cause infection if displaced into the bloodstream or surrou ...

'' and '' Acinetobacter'' spp., even when it is given alone. The activity of sulbactam against ''Acinetobacter'' spp. seen in in-vitro studies makes it distinctive compared to other β-lactamase inhibitors, such as tazobactam and clavulanic acid.

Chemistry

Ampicillin sodium is derived from the basic penicillin nucleus, 6-aminopenicillanic acid. Its chemical name is monosodium (2S, 5R, 6R)-6- R)-2-amino-2-phenylacetamido3,3-dimethyl-7-oxo-4-thia-1-azabicyclo .2.0eptane-2-carboxylate. It has a molecular weight of 371.39 grams and its chemical formula is C16H18N3NaO4S. Sulbactam sodium is also a derivative of 6-aminopenicillanic acid. Chemically, it is known as either sodium penicillinate sulfone or sodium (2S, 5R)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo .2.0eptane-2-carboxylate 4,4-dioxide. It has a molecular weight of 255.22 grams and its chemical formula is C8H10NNaO5S. Ampicillin/sulbactam is also used when the cause of an infection is not known ( empiric therapy), such as intra-abdominal infections, skin infections,

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severit ...

, and gynecologic infections. It is active against a wide range of bacterial groups, including ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

'',

Enterobacteriaceae Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but o ...

, and

anaerobic bacteria An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenat ...

. Importantly, it is not active against ''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic– facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. a ...

'' and should not be used alone when infection with this organism is suspected or known.

History

The introduction and use of ampicillin alone started in 1961. The development and introduction of this drug allowed the use of targeted therapies against gram-negative bacteria. With the rise of beta-lactamase producing bacteria, ampicillin and the other penicillin-derivatives became ineffective to these resistant organisms. With the introduction of beta-lactamase inhibitors such as sulbactam, combined with ampicillin made beta-lactamase producing bacteria susceptible.

Formulation

Ampicillin-sulbactam only comes in a parenteral formulation to be either used as intravenous or intramuscular injections, and can be formulated for intravenous infusion.Unasyn. DynaMed Web Site. It is formulated in a 2:1 ratio of ampicillin:sulbactam. The commercial preparations available include: *1.5 grams (1 gram ampicillin and 0.5 gram sulbactam) →Brand names: Unasyn, Unasyn ADD-Vantage, Unasyn Piggyback *3 grams (2 grams ampicillin and 1 gram sulbactam) →Brand names: Unasyn, Unasyn ADD-Vantage, Unasyn Piggyback *15 grams (10 grams ampicillin and 5 grams sulbactam) →Brand name: Unasyn

Society and culture

Names

* Unasyn (US) * Subacillin (Taiwan) * Unictam (Egypt) * Ultracillin (Egypt) * Fortibiotic * Sulbin (Egypt) * Novactam (Egypt) * Sulbacin (Kenya)

References

External links

* {{DEFAULTSORT:Ampicillin Sulbactam Penicillins Combination antibiotics Pfizer brands