Pharmacology and the dental patient Flashcards
What choices do we need to make before administrating a drug?
- Do we treat the patient?
- Which drug(s) do we use?
- What dose is appropriate
- Do we need to take any particular precautions?
As a dentist what drugs do we need to give patients?
1. Analgesics {Pharmacogenetics} 2. Sedation drugs 3. Antibiotics 4. Local anaesthetics 5. Vasoconstrictors
Name the most common type of odontogenic pain
Acute pain
Name three pain receptors
- Bradykinin
- Prostaglandins
- Substance P
What are Bradykinin released by?
Blood plasma
What are Prostaglandins released by?
By damaged cells
What is substance P released by?
nociceptors (sensory neurones)
Where do messages from the nociceptors travel to?
From the spinal cord to the thalamus
What happens to pain impulses at the thalamus?
They are distributes to various higher centres
Some also go to the reticular formation (governs alertness) and to the amygdala (a part of the limbic system involved in emotion)
What governs alertness?
The reticular formation
The amygdala is part of what?
a part of the limbic system involved in emotion
Name the most common type of analgesics used in dentistry
Non-opioid analgesics are the most common
What are Non-opioid analgesics used to treat?
They are drugs used to relieve tooth ache or pain following dental treatment
Give examples of non-opioid analgesics
- Ibuprofen
- Paracetamol (acetaminophen)
- Aspirin (acetylsalicylic acid)
What is an occasional side effect of ibuprofen?
Xerostomia that may increase oral plaque and dental caries
Give examples of some types of analgesics
- Corticosteroids
- Non-opioid analgesics
- Narcotic analgesics
Name some Corticosteroids
Orabase-HCA
Oracort
Oralone
What are Corticosteroids?
They are anti-inflammatory medications the are used to relieve discomfort and redness of the mouth
Give examples of Narcotic analgesics
Codeine Hydrocodone (Vicodin)
What are Narcotic analgesics used for?
For severe pain conditions
What is pharmacogenetics concerned with?
Pharmacogenetics is concerned with the identification of genetic variants that affect the responses to medications in patients
Why is pharmacogenetics important?
As some drugs work more or less effectively in some people than they do for others
What is codeine?
Codeine is an opiate used to treat mild to moderate degrees of pain.
Where is codeines active metabolite?
morphine
Where is codeine covered into its active metabolite?
In the liver
What is the catalysis for the conversion of codeine into morphine?
CYP2D6
What is a pro drug?
An inactive drug that must be metabolised to active drugs within the body
Give an example of a prodrug?
Codeine
What can happen if someone is a poor metaboliser of CYP2D6?
They will experience little to no analgesia from codeine since they lack the enzyme to metabolise the drug.
What is the conversion of codeine into morphine called and what type of pathway is it?
O-demethylation conversion
Represents a minor pathway of codeine metabolism (accounting for less than 10% of codeine clearance)
What percentage of the population are poor metabolisers of codeine?
7%-10% Caucasians
3%-6% Mexican Americans
2%-5% African Americans
1% Asians
What does it mean of you are a poor metaboliser of codeine?
It means the drug is metabolised very slowly so they may accumulate to toxic concentrations
What percentage of the population are intermediate metabolisers of codeine?
10%- 15%
What does it mean of you are an intermediate metaboliser of codeine?
It means the patient has a diminished capacity to metabolise drugs
Lower than average dosage may be more sufficient to achieve a therapeutic response
What percentage of the population are extensive metabolisers of codeine?
73%- 82%
What does it mean of you are a extensive metaboliser of codeine?
This is the typical rate of drug metabolism
What percentage of the population are ultra rapid metabolisers of codeine?
1%-2% Caucasians 4% North Americans 10% Greeks 10% Portugese 20% Saudia 30% Ethopians
What does it mean of you are an ultra rapid metaboliser of codeine?
It means the person has a higher than usual rate of drug metabolism
These drugs may not reach therapeutic concentration so the drugs may be ineffective at standard dosages
What did Sindrup’s investigation in the analgesic efficacy and kinetics of a single oral dose of 75 mg codeine show in respect to pain threshold?
They observed that codeine significantly increased pain thresholds to nocioceptive laser stimuli in Extensive Metabolisers but not in Poor metabolisers
What did Sindrup’s investigation in the analgesic efficacy and kinetics of a single oral dose of 75 mg codeine show in respect to morphine conc in urine ?
The study also observed that urine collected from Poor metabolisers had undetectable levels of morphine after a dose of codeine was administered.
But when the same dose was given to Extensive Metabolisers, measurable levels of morphine were detectable in their urine
The failure of poor metabolisers to convert codeine into morphine is demonstrated by which other molecules?
hydrocodone and oxycodone.
Which oral lesions are indicated for antibiotic use?
- Periodontal abscess
2. Acute necrotising ulcerative gingivitis
Which antibiotics are most commonly prescribed by dentist?
Penicillins
Name some Penicillins used in dentistry
- Amoxicillin,
- Penicillin V,
- Metronidazole
- Amoxicillin/clavulanate
Name the most popular penicillin used in dentistry
Amoxicillin
What are Penicillin V, amoxicillin and amoxicillin/clavulanate used to treat?
For the treatment of odontogenic infections
What is Metronidazole?
It is a nitroimidazole antibiotic medication
What is Metronidazole used to treat?
It is used to treat anaerobic bacteria and protozoa