DHE122 Lecture 4 chapter 7,8 2/26/18

• Pills
• Topical
• Liquids – IV form

• Dental caries
• Periodontal diseases
• Localized infections
• Systemic infections
• Drug of choice depends on many things

destroy infection

destroy or suppress bacterial growth

destroy or suppress bacterial growth. Often antinfective agents and antibiotic agents are used interchangeably

destroy or suppress growth of microorganisms

suppress or destroy the multiplication of fungi

suppress or destroy the multiplication of viruses

ability to kill bacteria – think homicidal

ability to inhibit the multiplication of bacteria

range of activity of a drug. Narrow spectrum kill small number of bacteria. Broad spectrum kill wide range of bacteria

• Bacterial resistance to the antibiotic
• Superinfections
• Gastrointestinal (nausea, vomiting, diarrhea)
• Allergic reactions
• Photosensitivity
• Drug interactions

• 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

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.

• 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).

• 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

• 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

Antibiotics can compete with other drugs in harmful ways

antibiotics increase the clearance of oral contraceptives in the body.

antibiotics reduce the bacteria that produce vitamin K needed in clotting, resulting in increased bleeding

• 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

• 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

• 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

• 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

Penicillins

Penicillins

• only pens used in dentistry
• for mild to moderate infections

i.e. Tetracyclines = ineffective Pen

ineffective contraceptives

ineffective Pen

caution!

• Antibiotic premed – infective bacterial Endocarditis
• Endodontic infections
• Periodontic infections
• Necrotizing ulcerative gingivitis (NUG)
• Refractory periodontitis – augmentin (amoxicillin + Clavulanic acid)

• 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

• 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

• 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

• 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

• 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