Pharmacology in Dental Hygiene Flashcards

What is the mechanism of action of metronidazole, and why is it effective against periodontal pathogens?

Answer: It is a prodrug activated in anaerobic organisms to form nitro radical anions that disrupt DNA, making it bactericidal against anaerobes including Porphyromonas gingivalis

Metronidazole is reduced by ferredoxin under anaerobic conditions to form toxic radical intermediates that cause DNA strand breaks, making it selectively lethal to strict anaerobes like major periodontal pathogens.

Which locally delivered controlled-release antibiotic device is FDA-approved for adjunctive use in periodontal pockets ≥5 mm?

Answer: Doxycycline hyclate 10% polymer gel (Atridox) and minocycline microspheres (Arestin)

Atridox (doxycycline 10% polymer gel) and Arestin (minocycline microspheres 1 mg) are the primary FDA-approved locally delivered antibiotic systems for adjunctive subgingival use in periodontal pockets.

A patient reports severe anxiety about dental treatment and requests 'something to calm them down.' The drug diazepam (Valium) belongs to which drug class, and what is its mechanism of action?

Answer: Benzodiazepine — positive allosteric modulator of GABA-A receptors, increasing chloride ion conductance and producing CNS depression

Diazepam is a benzodiazepine that enhances GABA-A receptor activity by binding at the benzodiazepine site, increasing the frequency of chloride channel opening, hyperpolarizing neurons, and producing anxiolysis and sedation.

Which drug interaction is MOST critical for a dental hygienist to recognize when a patient is taking monoamine oxidase inhibitors (MAOIs) for depression?

Answer: MAOIs can cause hypertensive crisis if combined with indirectly-acting sympathomimetic agents, and dangerous serotonin syndrome if combined with meperidine

MAO inhibitors prevent breakdown of catecholamines and serotonin; indirect sympathomimetics can cause severe hypertensive crisis, and meperidine (Demerol) can trigger fatal serotonin syndrome.

Fluoride works to prevent dental caries through which primary mechanism at the tooth surface?

Answer: Incorporation into hydroxyapatite to form fluorapatite, which is more acid-resistant, and promotion of remineralization during pH cycling

Fluoride's primary anticaries mechanism is ionic substitution in hydroxyapatite crystals to form fluorapatite (FAP), which has a higher critical pH, making enamel less susceptible to acid dissolution and facilitating remineralization.

What is the drug of choice for managing dental pain in a patient who is pregnant (second trimester)?

Answer: Acetaminophen (paracetamol) at recommended doses

Acetaminophen is the safest analgesic for pregnant patients at all trimesters; NSAIDs are contraindicated in the third trimester and avoided in the first/second, and opioids carry neonatal risk.