MJDF Pharmacology and Therapeutics 2

Question 1

What is the pharmacological basis for combining paracetamol and ibuprofen for post-operative dental pain?

Accepted Answer

They have different mechanisms of action (paracetamol: central COX inhibition and possible serotoninergic pathways; ibuprofen: peripheral COX-1 and COX-2 inhibition) providing additive or synergistic analgesia with fewer side effects than increasing the dose of either drug alone

Answer

They should never be combined as they interact dangerously

Answer

They have identical mechanisms and combining them offers no advantage

Answer

Combining them doubles the risk of liver damage

Question 2

A patient taking the oral contraceptive pill is prescribed a course of antibiotics for a dental infection. What is the current guidance regarding potential interaction?

Accepted Answer

Current UK guidance (FSRH and BNF) states that non-enzyme-inducing antibiotics (amoxicillin, metronidazole, clarithromycin) do NOT reduce the efficacy of combined hormonal contraception; additional contraception is NOT required. Only enzyme-inducing drugs (rifampicin, rifabutin) significantly reduce contraceptive efficacy

Answer

All antibiotics reduce the effectiveness of the oral contraceptive pill and additional contraception is always needed

Answer

Antibiotics enhance the effectiveness of the contraceptive pill

Answer

This interaction has never been studied

Question 3

What are the signs and symptoms of local anaesthetic toxicity and how should it be managed in the dental surgery?

Accepted Answer

Early signs include perioral tingling, metallic taste, tinnitus, light-headedness, and visual disturbance, progressing to tremors, seizures, respiratory depression, and cardiovascular collapse; management includes stopping injection, positioning supine, maintaining airway, administering oxygen, treating seizures with IV midazolam, and calling 999 — IV lipid emulsion (Intralipid 20%) is the specific antidote for severe cardiovascular toxicity

Answer

LA toxicity only causes numbness and has no systemic effects

Answer

LA toxicity is always fatal and cannot be treated

Answer

It presents as an allergic rash only

Question 4

What is the mechanism of action of metronidazole and why is alcohol consumption contraindicated during its use?

Accepted Answer

Metronidazole enters anaerobic bacteria where it is reduced to form cytotoxic intermediates that damage bacterial DNA; alcohol is contraindicated because metronidazole inhibits aldehyde dehydrogenase, causing accumulation of acetaldehyde leading to a disulfiram-like reaction (nausea, vomiting, flushing, headache, tachycardia)

Answer

Metronidazole inhibits cell wall synthesis; alcohol is contraindicated because it reduces absorption

Answer

Metronidazole inhibits protein synthesis; alcohol enhances its antibacterial effect too much

Answer

Metronidazole has no interaction with alcohol — this is a myth

Question 5

What are the key considerations when prescribing analgesics for a pregnant patient experiencing dental pain?

Accepted Answer

Paracetamol is the first-line analgesic throughout pregnancy; NSAIDs (ibuprofen) should be avoided after 28 weeks (risk of premature closure of the ductus arteriosus) and used with caution before this; codeine should be used at the lowest effective dose for the shortest duration; aspirin is contraindicated in the third trimester

Answer

All analgesics are safe during pregnancy

Answer

No analgesics can be given during pregnancy under any circumstances

Answer

Opioid analgesics are the first-line choice in pregnancy

Question 6

What is antimicrobial resistance and how can dental practitioners contribute to antimicrobial stewardship?

Accepted Answer

Antimicrobial resistance occurs when bacteria evolve mechanisms to survive antibiotic exposure; dental practitioners contribute to stewardship by prescribing antibiotics only when clinically indicated, choosing narrow-spectrum agents, using appropriate doses and durations, prioritising drainage/removal of the cause over antibiotics alone, and following evidence-based prescribing guidelines (FGDP/SDCEP)

Answer

Antimicrobial resistance is not relevant to dentistry

Answer

Dental practitioners should prescribe antibiotics for every patient to prevent resistance

Answer

Antimicrobial resistance can be prevented by using antibiotics prophylactically for all procedures