ORE Part 1 Pharmacology in Dentistry 2 — Questions and Answers
Question 1: What is the mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs) in dentistry?
- Inhibit cyclo-oxygenase (COX) enzymes, reducing prostaglandin synthesis, decreasing pain, inflammation, and fever (Correct answer)
- Block opioid receptors
- Reduce bacterial infection
- Stimulate endogenous endorphin release
Correct answer: Inhibit cyclo-oxygenase (COX) enzymes, reducing prostaglandin synthesis, decreasing pain, inflammation, and fever
NSAIDs (ibuprofen, diclofenac) inhibit COX-1 and COX-2, reducing prostaglandin synthesis at sites of inflammation. This reduces sensitisation of peripheral nociceptors, providing analgesic and anti-inflammatory effects.
Question 2: According to the BNF, what is the first-line analgesic for post-extraction dental pain?
- Ibuprofen 400 mg three times daily (if not contraindicated) or paracetamol 1g four times daily (Correct answer)
- Codeine phosphate alone
- Tramadol
- Opioid patch
Correct answer: Ibuprofen 400 mg three times daily (if not contraindicated) or paracetamol 1g four times daily
For post-extraction pain, ibuprofen 400 mg TDS is first-line if no contraindications. Paracetamol 1g QDS is used if NSAIDs are contraindicated. Combination (ibuprofen + paracetamol) provides superior analgesia to either alone.
Question 3: What antibiotic is recommended by SDCEP guidelines for dentoalveolar infections with systemic features?
- Amoxicillin 500 mg three times daily for 5 days (or metronidazole 400 mg TDS if penicillin allergic) (Correct answer)
- Ciprofloxacin as first-line
- Erythromycin as first-line
- Doxycycline as first-line
Correct answer: Amoxicillin 500 mg three times daily for 5 days (or metronidazole 400 mg TDS if penicillin allergic)
Scottish Dental Clinical Effectiveness Programme (SDCEP) and NICE guidelines recommend amoxicillin as first-line antibiotic for acute dentoalveolar infection with systemic spread. Metronidazole or phenoxymethylpenicillin are alternatives.
Question 4: What is the recommended management of a patient on warfarin requiring a simple dental extraction?
- Do NOT stop warfarin; check INR within 24–72 hours of procedure; if INR ≤4.0 proceed with local haemostatic measures (packing, sutures, haemostatic dressings) (Correct answer)
- Always stop warfarin 5 days before extraction
- Refer all warfarinised patients to hospital
- Reverse warfarin with vitamin K before any extraction
Correct answer: Do NOT stop warfarin; check INR within 24–72 hours of procedure; if INR ≤4.0 proceed with local haemostatic measures (packing, sutures, haemostatic dressings)
SDCEP/NICE guidance: patients on warfarin should NOT routinely stop their anticoagulation for simple extractions. Check INR within 72 hours. If ≤4.0, proceed with local haemostatic measures. Stopping warfarin risks systemic thromboembolism.
Question 5: What is the clinical significance of prescribing metronidazole to a patient drinking alcohol?
- Metronidazole inhibits acetaldehyde dehydrogenase causing a disulfiram-like reaction: flushing, nausea, headache, and cardiovascular effects with even small amounts of alcohol (Correct answer)
- No significant interaction
- Alcohol increases metronidazole absorption only
- Only relevant with IV alcohol use
Correct answer: Metronidazole inhibits acetaldehyde dehydrogenase causing a disulfiram-like reaction: flushing, nausea, headache, and cardiovascular effects with even small amounts of alcohol
Metronidazole blocks acetaldehyde dehydrogenase, causing acetaldehyde accumulation when alcohol is consumed. This disulfiram-like reaction causes severe flushing, nausea, vomiting, headache, and palpitations.
Question 6: What is the pharmacological basis for prescribing prophylactic amoxicillin before dental procedures?
- Current NICE guidance (NG178, 2008 updated) no longer recommends routine antibiotic prophylaxis for infective endocarditis in at-risk patients undergoing dental procedures in the UK (Correct answer)
- All cardiac patients require amoxicillin before dentistry
- Prophylaxis is mandatory for all implant procedures
- Routine prophylaxis prevents bacteraemia
Correct answer: Current NICE guidance (NG178, 2008 updated) no longer recommends routine antibiotic prophylaxis for infective endocarditis in at-risk patients undergoing dental procedures in the UK
NICE guideline NG178 (2008, updated 2016): antibiotic prophylaxis for infective endocarditis prevention is NOT recommended for any dental procedure in at-risk patients in the UK — in contrast to previous practice and some international guidelines.
ORE Part 1 Pharmacology in Dentistry 2
What is the mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs) in dentistry?