Routine antibacterial chemotherapy for the treatment of uncomplicated odontogenic infections, in the absence of timely debridement, i.e., primary dental care, has not been shown to be effective.11,12,15,20,71,80-87,89-93,97-102 Consequently, clinicians should avoid "rational activism" and "reflex prescribing." The rational activist assumes that it is better to over-treat than not to treat at all; the reflex prescriber caters to the patient’s expectations regardless of the diagnosis.
Uncomplicated odontogenic infections that have not been debrided in a timely manner or have failed to respond to debridement may spread, especially in immunocompromised patients, into anatomical spaces contiguous with fascial planes and can lead to serious, even life-threatening infections.15,103 Adjunctive antibacterial chemotherapy, predicated on sound principles, is imperative in the treatment of complicated odontogenic infections (Table 2).71,103,104
Based on best available evidence, penicillin V potassium or amoxicillin formulations, alone or in combination with metronidazole; and clindamycin are reasonable empirical options to consider for the treatment of complicated odontogenic infections (Figure 10).11,42,71 Azithromycin may be an empirical option in some instances. Ultimately, the empirical drug of choice should be an effective agent with the narrowest spectrum and the least potential for adverse drug effects.
Primary Line of Antibacterial Chemotherapy
Unless the patient has an allergy to the penicillins, the empirical drug of first choice for the treatment of odontogenic infections is narrow spectrum penicillin V potassium (Table 3).9,20,42 Most infections require 5 days of antibacterial chemotherapy. An initial loading dose is followed by maintenance doses for the remainder of the time. It is prudent to schedule the patient for a follow-up in 2 to 3 days. This will provide an opportunity to assess response to treatment. Hypersensitivity reactions are potentially the most serious adverse drug effects (see the Prescription-precautions Associated with the Administration of Antibacterial Agents section).105
Table 3. Empirical Antibacterial Agents for the Treatment of Complicated Odontogenic Infections.
|Primary line of treatment:||Rx|
||Penicillin V potassium, 500 mg tablets
Disp. 21 tablets
Sig. Take two tablets stat, then one tablet four times a day for 5 days.
||Metronidazole, 500 mg tablets
Disp. 21 tablets
Sig. Take one tablet stat, then one tablet four times a day 5 days.
|Secondary line of treatment:||Rx|
||Azithromycin, 250 mg tablets
Disp. 6 Tablets
Sig. Take two tablets stat, then one tablet a day for 5 days.
|Tertiary line of treatment:||Rx|
||Clindamycin, 300 mg capsules
Disp. 21 tabs
Sig. Take two capsules stat, then one capsule four times a day for 5 days.
|*Pediatric dosages: penicillin V potassium, 25-50 mg/kg/day, divided q6-8h; metronidazole, 30 mg/kg/day, divided q6h; azithromycin, 5-10 mg, once daily; clindamycin, 10 mg/kg, q8h. Pediatric dosages should not exceed maximum adult doses.
** Metronidazole is added in addition to, not in lieu of, penicillin V regimen.
If significant improvement is not noted in 48 to 72 hours, the empirical addition (for 5 days) of metronidazole to penicillin V potassium is reasonable. Metronidazole is β-lactamase resistant and it provides excellent coverage for obligate anaerobes (Table 3).61,106,107 The safety and effectiveness of metronidazole in pediatric patients have not been established. In patients receiving metronidazole, the concurrent use of alcohol may produce severe gastrointestinal symptoms; serious convulsive seizures and peripheral neuropathy has also been reported (see the Prescription-precautions Associated with the Administration of Antibacterial Agents section).
Secondary Line of Antibacterial Chemotherapy
A macrolide is an empirical option for the treatment of odontogenic infections in patients allergic to β-lactam antibiotics. While there is a paucity of data demonstrating the efficacy of azithromycin in the treatment of odontogenic infections, among macrolides it may be the best alternative because of its extended spectrum against facultative and some obligate anaerobes (Table 3).75,76 However, a recent FDA drug safety communication warns about the risk of QT prolongation and cardiac arrhythmias (see the Prescription-precautions Associated with the Administration of Antibacterial Agents section).108
It is also of note, that the single most important driver of the emergence of macrolide resistance in vivo is macrolide use.109 Macrolide-resistant organisms can block ribosomal macrolide-receptor sites, and because of receptor-site overlap, these organisms will also be resistant to clindamycin; and efflux pump-related macrolide-resistance also affects the intracellular concentration of β-lactam antibiotics and β-lactamase inhibitor, i.e., macrolide-resistance often confers multidrug-resistance. Clindamycin may also be an empirical option (see below).110
Tertiary Line of Antibacterial Chemotherapy
Clindamycin is the empirical drug of choice for unresolved infections following treatment with a β-lactam antibacterial agent.71,111 It is also the initial empirical drug of choice for the treatment of severe complicated odontogenic infections (Table 3).15,50,51,112,113 It is β-lactamase resistant and has excellent activity against gram-positive cocci and most gram-negative anaerobes.47,50,112,114-117 However, the risk of Clostridium difficile-associated superinfections, which may range in severity from mild diarrhea to fatal colitis, should prompt caution and mandates close follow-up (see the Prescription-precautions Associated with the Administration of Antibacterial Agents section).118,119