Pharmacology 2

Question 1

Pain perception:

site of injury?

Answer 1

Bradykinin is released by blood plasma

Prostaglandins are released by damaged cells

In response to this Substance P is released by nociceptors (sensory neurones). Stimulates and sensitizes the nociceptors into hyperalgesia.

Question 2

Pain perception after the stimulation of nociceptors?

where do messages go?

Answer 2

Most nerves that carry messages from the nociceptors up the spinal cord go to the thalamus, where they are distributed to various higher centres, e.g. somatosensory cortex

Some also go to the reticular formation (governs alertness) and to the amygdala (a part of the limbic system involved in emotion)

Question 3

Analgesics

Answer 3

Non-opioid analgesics are the most commonly used drugs for relief of toothache or pain following dental treatment

The commonly used medications used are:
Ibuprofen
Paracetamol (acetaminophen)
Aspirin (acetylsalicylic acid)

Question 4

PRoblem associated with ibuprofen?

Answer 4

Ibuprofen occasionally causes xerostomia (dry mouth) that may increase oral plaque and dental caries (cavities)

Question 5

Corticosteroids- what are they and some examples?

Answer 5

Corticosteroids are anti-inflammatory medications that are used to relieve discomfort and redness of the mouth
E.g. Orabase-HCA, Oracort, and Oralone

Question 6

Narcotics?

Answer 6

Opioid drug
Analgesics for more sever pain conditions
e.g. codeine or hydrocodone (Vicodin)

Question 7

Pharmacogenetics

Answer 7

Pharmacogenetics is concerned with the identification of genetic variants that affect the responses to medications in patients.

Question 8

CYP2D6 gene and its relevance with codeine

Answer 8

The conversion of codeine to its active metabolite morphine occurs in the liver and is catalyzed by CYP2D6.

Given that codeine is a prodrug (inactive drug that must be metabolized to activate drug in the body) people who are poor metabolizers of CYP2D6 will experience little to no analgesia from this medication since they lack the enzyme to metabolize the drug.

Question 9

Nitrous oxide N2O?

4 levels of sedation?

Answer 9

Mild sedative and analgesic
It helps with anxiety and it offers some degree of painkilling ability

4 levels of sedation:

• A tingling sensation, especially in the arms and legs, or a feeling of vibration (“parasthesia”)
• Warm sensations
• A feeling of well-being, euphoria and/or floating
• Sleepiness, difficulty in keeping one’s eyes open or speaking

Question 10

Midazolam

What is it? How is it given? onset? how does it work?

Answer 10

A benzodiazepine.
Sedative - intravenous - adult patients, has a fast onset as it sedates within 1 /2 minutes.
Works by slowing down both the health rate and rate of breathing (CNS depressant)

Question 11

Midazolam how it works? properties of sedative?

Answer 11

Benzodiazepines enhance the effect of the inhibitory neurotransmitter GABA at the GABAA receptor, resulting in sedative, hypnotic (sleep-inducing), anxiolytic (anti-anxiety), euphoric, anticonvulsant, and muscle relaxant properties

Question 12

Risk of Midazolam

Answer 12

The concomitant use with other CNS depressants, may increase the possibility of hypotension, respiratory depression, respiratory arrest, and death, even at therapeutics doses.
Can be addictive if administered repeatedly

Question 13

Midazolam recovery? 2 stages

Recommendation for those that have taken?

Answer 13

2 phases:

• Recovery from sedation (“street fitness”)
• Recovery from psychomotor impairment

People who take midazolam are recommended not to drive or to operate machinery for 24 hours after administration

Question 14

Antibiotics

- What is the main type of antibiotic and how does it work?

Answer 14

Medication for orofacial infections
Most antibiotics are antibacterials with
bactericidal activity: they inhibit various bacterial cell processes

Question 15

Most commonly described names of antibiotics?

Answer 15

Penicillins are the most commonly prescribed antibiotics by dentists, the most popular one being amoxicillin, followed by penicillin V, metronidazole and amoxicillin/clavulanate

Question 16

Types of localised oral lesions that may require antibiotic use?

Answer 16

Periodontal abscess and acute necrotizing ulcerative gingivitis= localized oral lesions that are indicated for antibiotic use.

Question 17

Metronidazole

Answer 17

Metronidazole is a nitroimidazole antibiotic medication used particularly for anaerobic bacteria and protozoa

Used to treat dental infections of bacterial origin, such as periapical abscess, periodontal abscess, acute pericoronitis of impacted or partially erupted teeth

Question 18

Affect of Metronidazole and alcohol use

Answer 18

Consuming alcohol while taking metronidazole has long been thought to have a disulfiram-like reaction with effects that can include nausea, vomiting, flushing of the skin, tachycardia (accelerated heart rate), and shortness of breath

Question 19

Short course antibiotics - ideal characteristics:

Answer 19

• Rapid onset of action
• Bactericidal activity
• Lack of propensity to induce resistant mutants
• Easy penetrability into tissues
• Activity against non-dividing bacteria
• Not being affected by adverse infection conditions (low pH, anaerobiasis, presence of pus, etc.)
• Administration at an optimal dose
• Optimal dosing regimen

Question 20

Prolonged courses of antibiotics may result in:

Answer 20

• Normal resident oral/gut flora being destroyed
• Selection of resistant strains
• Colonization by harmful micro-organisms that are not normal residents, e.g. multi-resistant bacteria and yeasts

Question 21

Link between antidepressants and xerostomia

How is it caused and what are the effects?

Answer 21

Some antidepressants block the action of the neurotransmitter acetylcholine. Acetylcholine controls the function of the gastrointestinal tract.
Blocking acetylcholine reduces the production of mucus and saliva secretions causing dry mouth (xerostomia).

If left untreated, xerostomia could lead to rampant tooth decay, periodontal disease (gum disease), bad breath, oral yeast infection and other oral health problems

Question 22

Link between Nitrates and headache?

Answer 22

Nitrates (commonly nitroglycerin) are used to prevent and relieve chest pain (angina) due to coronary artery disease.
Nitrates = vasodilators- cause blood vessels to widen
Common side effects of nitrates are a throbbing headache (50% of people)
The pain can also radiate towards the forehead, the jaw, the throat, the ear, to the back of the head, or, in rare cases, to the neck and to the shoulder. This is because the TRIGEMINAL nerve gets affected.

Question 23

Link between Antihypertensives and postural hypotension?

Postoral hypotension?

Answer 23

Postural (orthostatic) hypotension is an excessive fall in blood pressure when an upright position is assumed
Symptoms of faintness, light-headedness, dizziness, confusion, or blurred vision occur within seconds to a few minutes of standing
The most common causes of chronic orthostatic hypotension include:
- Age-related changes in BP regulation
- Vasodilatation from antihypertensive drugs
- Autonomic dysfunction

Question 24

Link between Opioids and addiction-related behaviour:

Answer 24

Opioids and addiction-related behaviour

• Opioid analgesics (e.g. codeine) are sometimes used for chronic orofacial pain that is refractory to most non-opioid therapy
• With long-term therapy there is the potential risk of developing opioid tolerance, dependence, or addiction
• Heroin addicts, and abusers of other drugs, often have poor dental health due to neglect
• The primary oral effect of heroin use is dental decay

Question 25

Insulin and oral hypoglycaemics

Answer 25

People with diabetes face a higher risk of:

• Dry mouth
• Gum inflammation
• Poor healing of oral tissues
• Thrush (yeast thrives on the high levels of sugar in the saliva of people with uncontrolled diabetes)

The most common complication of diabetes therapy that can occur in the dental surgery is a hypoglycaemic episode (a severe decline in blood glucose levels)
Oral infections or dental procedures can affect food intake in diabetics

Question 26

Steroids

Answer 26

Synthetic corticosteroids (e.g. Dexamethasone)= developed for their anti-inflammatory and immunomodulatory effects
Patients on steroids ~increased risk of surgery complications because of:
- Adrenal suppression caused by steroid therapy
- Disease or condition which required them to take steroids
- Long-term and other side-effects of steroid therapy

Chronic usage of steroid inhalers (e.g. for asthma) make the patient susceptible to oral yeast infection and blood blisters

Question 27

β-blockers

Selective and non selective

Answer 27

β-blockers are used for their ability to block sympathetic influences on cardiac β1 adrenoreceptors. This interaction will not occur in those patients receiving selective β1 antagonists

Older agents are non-selective and also block β2 receptors on systemic arteries.
Patients medicated with non-selective β-blockers have heightened sensitivity to the systemic effects of vasopressors
These patients have a significant risk for acute hypertensive episodes if they receive vasopressors contained in local anaesthetics, e.g. epinephrine

Question 28

Affect of β-blockers on kidney

Answer 28

• β-blockers can decrease hepatic blood flow and/or inhibit hepatic enzymes, resulting in the reduced metabolism of lidocaine (local anaesthetic)
• This may lead to increased serum levels and, possibly, toxicity of lidocaine
• Concomitant administration of a β-blocker and lidocaine may result in myocardial depression

Question 29

Monoamine oxidase inhibitors

Answer 29

Monoamine oxidase inhibitors (MAOI) were the first class of drugs used to treat depression
They elevate norepinephrine and serotonin levels by limiting their oxidation by the enzyme monoamine oxidase (MAO)
Major drawback of this drug class is potential for drug interactions, many of which precipitate an acute hypertensive crisis
Potential for an interaction between MAOI and vasoconstrictors to cause acute hypertensive crisis

Question 30

Warfarin and antiplatelet drugs

Expression of activity?

Answer 30

Warfarin is an anticoagulant which inhibits synthesis of the vitamin K-dependent coagulation factors II, VII, IX and X
The activity of warfarin is expressed using the international normalised ratio (INR)
A normal coagulation profile has an INR of 1.0
The risk of bleeding increases exponentially as the INR rises,e.g. INR=5 indicates a high chance of bleeding

Question 31

Bisphosphonates

What affect does it have on bone and how does this link to oral surgery?

Answer 31

Bisphosphonates are used to prevent bone resorption in osteoporosis and bone cancer
Bisphosphonate usage is associated with ‘Bisphosphonate-associated osteonecrosis of the jaw (BON)’
Exposure of dead bone (osteonecrosis) in jaws
By suppressing bone resorption, any damaged bone will be left in situ instead of being resorbed.
Usage leads to surgical complication in the form of impaired wound healing following oral or periodontal surgery or endodontic therapy.