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Antinfective agents different types of forms?
- Pills
- Topical
- Liquids – IV form
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Antinfective agents are Used to treat dental diseases such as?
- Dental caries
- Periodontal diseases
- Localized infections
- Systemic infections
- Drug of choice depends on many things
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Antinfective agents-
destroy infection
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Antibacterial –
destroy or suppress bacterial growth
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Antibiotic agents –
destroy or suppress bacterial growth. Often antinfective agents and antibiotic agents are used interchangeably
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Antimicrobial agents –
destroy or suppress growth of microorganisms
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Antifungal agents –
suppress or destroy the multiplication of fungi
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Antiviral agents –
suppress or destroy the multiplication of viruses
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Bactericidal –
ability to kill bacteria – think homicidal
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Bacteriostatic –
ability to inhibit the multiplication of bacteria
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Spectrum –
range of activity of a drug. Narrow spectrum kill small number of bacteria. Broad spectrum kill wide range of bacteria
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Antinfective agents Adverse Reactions?
- Bacterial resistance to the antibiotic
- Superinfections
- Gastrointestinal (nausea, vomiting, diarrhea)
- Allergic reactions
- Photosensitivity
- Drug interactions
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Resistance -
- Natural or acquired ability of an organism to be immune to or resist the effects of an anti-infective agent.
- Overuse of antibiotics results in antibiotic-resistant bacteria.
- Resistant bacteria causes infection to progresses – results in death
- Antibiotic no longer effective against bacteria
- Worldwide problem
- Prevention – resist prescribing antibiotics unless necessary. Pt needs to take until finished
- Antibiotics not effective against viruses. Fifty million rx each year to treat viral respiratory infections
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Adverse reaction Superinfections –
infection occurs when broad spectrum antibiotics are used to destroy microorganisms that are part of the normal flora. Reduction/elimination of normal bacterial results in growth of other organisms like fungi can occur, as seen with Candida infections.
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adverse reaction Gastrointestinal Problems?
- Antibiotics affect the GI track either by direct or indirectly changing the normal flora, resulting in nausea, vomiting, and/or diarrhea.
- Antibiotic-associated pseudomembranous colitis reported with all antibiotics. Occurs when there is an overgrowth of the bacteria Clostridium difficile.
- To avoid GI upset patient should take antibiotic with food or take with Lactobacillus acidophilus (gel caps).
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antibiotic Allergic reactions?
- Can be immediate in response – life threatening – anaphylactic response
- Mild rash
- penicillins and cephalosporins tend to cause allergic reactions more than other antibiotics
- Many agents, such as erythromycin and clindamycin have low allergic potential
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Photosensitivity adverse reaction:
- Exposure to the sun causes an exaggerated sunburn
- Should stay away from sun exposure while taking the drug
- ciprofloxacin (a quinolone) and doxycycline (a tetracycline) known to cause photosensitivity
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Drug interactions
Antibiotics can compete with other drugs in harmful ways
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Antibiotics and oral contraceptives drug interactions:
antibiotics increase the clearance of oral contraceptives in the body.
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Antibiotics and anticoagulants drug reactions–
antibiotics reduce the bacteria that produce vitamin K needed in clotting, resulting in increased bleeding
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Antibiotics during Pregnancy:
- Antimicrobial agents should be limited during pregnancy
- Antibiotics like tetracyclines have shown to damage teeth and skeleton defects
- Antibiotics that can be safely used are penicillin, erythromycin and metronidazole but MD should be consulted
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Antibiotics in dentistry are indicated for three primary purposes:
- Treatment of acute odontogenic/orofacial infections
- Prophylaxis against infective endocardititis
- Prophylaxis for patients at risk for infection due to compromised host defense, i.e. diabetics who don’t heal well or to prevent infection when implant is placed
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Selection of antibiotic is based on?
- Antibiotic is chosen based on knowledge on the type of bacteria expected to be found at the infection.
- Site specific antibiotics used for aggressive periodontitis
- Systemic antibiotics not indicated if there is an infection but the infection is asymptomatic. i.e., draining fistula
- Systemic antibiotics are indicated when there is an infection and it is symptomatic
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Penicillins – (cousins –amoxicillin, augmentin and ampicillin)
- Bactericidal or static depending on dosage
- Administered either orally or parenterally – (injections or inhalation)
- Never topically - causes severe allergic reactions
- Effective against gram negative bacteria
- Absorption depends on acid stability of stomach. Pen is absorbed in small intestines and best taken on empty stomach.
- Exception – amoxicillin taken with food
- Pens eliminate through kidneys – renal failure
- Destroys the bacterial cell wall
- Effective against rapidly growing organisms
- Can be given to pregnant women
- amoxicillin not effective against penicillinase
- Clavulanic acid in combination with amoxicillin is known as Augmentin
- PenVK – preferred over PenG
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What is the Most commonly prescribed antibiotic in dentistry?
Penicillins
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Antibiotic Most likely to produce anaphylactic response?
Penicillins
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Pen VK and Amoxicillin:
- only pens used in dentistry
- for mild to moderate infections
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Pen + bacteriostatic antibiotics,
i.e. Tetracyclines = ineffective Pen
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Pen + oral contraceptives =
ineffective contraceptives
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Pen + food =
ineffective Pen
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Pen + nursing mother =
caution!
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Penicillins used in dentistry for:
- Antibiotic premed – infective bacterial Endocarditis
- Endodontic infections
- Periodontic infections
- Necrotizing ulcerative gingivitis (NUG)
- Refractory periodontitis – augmentin (amoxicillin + Clavulanic acid)
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Cephalosporins:
- Bactericidal – kill cell wall of bacteria
- Broad spectrum antibiotics against anaerobes – expensive
- Not indicated for perio or endo
- Drug interactions with warfarin – increased anticoagulant effects,
- Probenicid + cephalosporins = ineffective cephalosporin
- Cephalosporins + nursing mother = fetus getting antibiotic
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Nitroimadazoles:
- metronidazole
- Effective against strict anaerobes
- Bactericidal
- Breaks down bacterial DNA
- Used against NUG and refractory perio
- Can be used in combination with Augmentin – best for refractory perio
- Resistance is rare but many side effects
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Metronidazole
- Effective against anaerobes only
- Can produce and antabuse reaction so no alcohol consumption when using this product
- Side effect – secondary fungal infections-candidiasis
- People have allergic reactions to this drug
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Metronidazoles side effect:
- GI upset
- Metronidazole + Alcohol = vomiting, cramps. Alcohol in Mouthrinses need to be watched. No Alcohol for 3 days post tx
- Contraindicated when taking Lithium and Cimetidine
- Metronidazole + anticoagulants = increased bleeding
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Quinolones (Fluoroquinolones):
- Bactericidal – inhibit DNA replication
- Referred to as broad spectrum antibiotics but technically not antibiotics.
- Good against gram negative anaerobes
- Indicated for chronic perio, sinusitis, pneumonia
- Common dental Quinolones is ciproflaxin
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