Removable pros and special care Flashcards
1
Q
What are immediate dentures?
A
Dentures inserted on the same day that teeth are extracted. Can be partial or full dentures.
2
Q
What are advantages of immediate dentures?
A
- aesthetics
- speech
- may maintain function
- avoid drifting/tilting of remaining teeth
- self esteem
3
Q
What are disadvantages of immediate dentures?
A
- a space is likely to develop between denture and ridge as healing occurs
- may need replaced after initial resorption
4
Q
What are the clinical stages immediate dentures?
A
Same sequence as for partial dentures
1. Examination and assessment: teeth to be removed are assessed clinically radiographically if required.
2. Impressions: accurate, fully extended - use alginate in stock trays
3. Occlusion: Index teeth may be present
4. Design: always simple acrylic plate
5. Second impressions: special tray
6. Try-in: limited to those teeth already missing, check extensions, occlusion, shade.
7. Extractions and finish: care with extractions and insertion of denture.
Check dentures before extractions
5
Q
What instructions should you give to the lab for immediate dentures?
A
- Which teeth are to be extracted
- Arrangement
- Shade
- Flange type e.g full, part, flangeless
- Material
- Date for denture to be ready for insertion.
6
Q
What post-op instructions should you give to the patient and what appointments should be made after fitting immediate dentures?
A
- Dentures to be kept in 24 hours- post op instructions
- Review app usually on day after insertion (remove dentures and examine mouth for healthy clots, identify areas of inflammation and ease denture.)
- After 24 hours advise warm saline mouthwash and pt to remove denture at mealtimes, to rinse mouth and clean denture - soft toothbrush and soap and water.
- Review after 1 week (further adjustment required)
- Review after 1 month (assess adaption)
- Consider temporary reline
- Need for regular recall e.g 6/12
7
Q
What is working impressions?
A
Use of a special tray allowing refining of tray adaptation to a resorbed or awkwardly shaped ridge.
- Always check the fit and placement of special tray prior to impression
- Can modify if required
- Should record both the depth and width of the sulcus for appropriate flange length and width.
8
Q
What impression technique can you do for a patient with a fibrous/flabby ridge?
A
- Single stage imp can be used with perforated tray and low viscosity material
- If more severe can do a 2 stage impression eg mucocompressive imp for the non-compressible tissues then mucostatic imps for the fibrous area.
9
Q
How would you solve poor survey lines that are needing modified for the denture?
A
Add composite onto teeth to create an undercut where clasps can be added. Overall improves denture retention.
10
Q
What would you do for a patient requiring fixed pros that is an abutment for making a denture?
A
Crown made first although can make both at same time; dentists need to coordinate different technicians; impression needs to be accurate for crown preparation and denture bearing area; ensure preparation has space for rest seats and guide plane; denture design must be done before crown preparation.
11
Q
What are precision attachments?
A
Mostly used in overdentures, can be placed on a tooth and crown and acts as a clip to go into the denture for improving retention in that area.
12
Q
Whats the disadvantages of using precision attachments?
A
- technically demanding
- difficult to fix/repair
13
Q
When is a two part denture useful?
A
Gross tissue loss and different paths of insertion.
14
Q
How does a two part denture work?
A
Part of the denture is inserted, then the other part is inserted into a slot therefore joins together.
15
Q
What is a swinglock denture?
A
Lock and hinge acts as a gate (open when placing denture and closes when denture is in place), engages bone and tissue undercuts for retention. Good oral hygiene essential. Technically demanding.
16
Q
How could you manage a patient that has lingually tilted teeth that makes it difficult for a connector to be placed lingually?
A
Create a buccal bar instead of a lingual bar.
17
Q
What modifications can you do to prevent a denture from breaking for a patient who is a burxist wearing a denture?
A
- Put metal to the back of the teeth
- Use cobalt chrome instead of acrylic as this is stronger
- High impact acrylic if using this
- Can extend cobalt chromium onto occlusal surfaces of the teeth
- When selecting teeth you can select cross linking teeth which are most resistant to wear
- Use acrylic postdam to improve retention of denture so patient less likely to dislodge.
18
Q
What would you explain to your patient when doing a try in of a denture?
A
There will be a difference in retention, mouth feel and colour of flanges compared with finished prosthesis.
- Will feel bulky
- SS clasps will not be engaged therefore not providing retention.
- Post dam will also provide retention
19
Q
Give a list of the checks you would take when doing a try in stage.
A
Lip support
Incisal level
Occlusal planes - anterior/posterior
Retention and stability
Position of teeth compared with the ridge
Base extensions
Vertical extensions
Even contact on occlusion when in RCP
Speech
Aesthetics
20
Q
What would you do if theres an error with aesthetics at try in e.g shade/mould of teeth?
A
Can take clinical photos to send to lab or prescribe for new shade/mould and have another re-try
21
Q
How would you manage if the denture is over extended at the try in?
A
Can trim this chairside and go to finish at next appointment if this is corrected.
22
Q
How would you manage errors in the adaptation of a try in of a denture?
A
Re-take another impression to improve adaptation then do a re-try appointment.
23
Q
How would you manage errors with the chrome framework at the trial appointment?
A
Errors with either the wax up or the impression- new impression should be taken with a new casting and wax up done then another re-try appointment. Can occasionally be that small adjustments can be made chairside to be fixed and therefore doesnt need to be taken to re-try.
24
Q
How would you manage and error with the occlusion eg left hand side meeting however right hand side has open bite?
A
Check FWS: if increased then decrease height on the left hand side
If FWS normal the increase height on the right hand side.
This should be carried out again on the wax blocks and occlusion should be re-recorded
25
What should you prescribe for at the end of the try in stage?
Post dam; depth and location
Type of acrylic used
Any changes prior to the finish.
26
What insertion checks should you carry out when fitting a denture?
comfort
retention and stability - ensure clasps are engaged
base extensions
appearance
speech
occlusion uneven? - check with artic paper
Vertical dimensions
27
What instructions should you give to the patient after fitting a denture?
- oral hygiene instructions: take out at night, how to clean denture
- make 1 week review
- normal for speech to be altered but try to chat to themselves.
- increased salvia production normal
- eat softer food to start with
- perseverance required
28
Why should you ask a patient to wear their denture 24 hours before the ease appointment?
- can more easily highlight areas of redness/ulceration that would need adjusting.
29
Where are common areas to check at the ease visits?
The frenum, the tuberosity areas and at the depth of sulci.
30
How often are patients with full dentures recalled?
annually
31
What are the 5 most common substances of misuse in scotland?
Cannabis
Cocaine
Ecstasy
Amphetamines
Heroin
32
Why is cocaine mixed with alcohol so dangerous?
Cocaethylene produced x3 alcohol consumption
33
How many times are you more likely to have a heart attack taking cocaine?
24 times more likely.
34
Name some substances that are stimulants.
- Caffeine
- Nicotine
- Cocaine
- Amphetamine
- Ecstasy
35
Name some substances that are depressants.
- Alcohol
- Solvents
- Heroin
- Morphine
- Benzodiazepines
36
What are some hallucinogenics drugs?
- LSD
- Magic mushrooms
- Cannabis
37
What are the 2 main laws/statutes relating to substance misuse?
- The medicines Act 1968
- The Misuse of Drugs Act 1971
38
Name some Class A drugs under the Misuse of Drugs Act?
- Heroin
- Cocaine (including crack)
- Methamphetamine
- Ecstasy
- Methadone
39
Name for Class B drugs under the Misuse of Drugs Act?
- Amphetamines
- Cannabis*.
40
Name for Class C drugs under the Misuse of Drugs Act?
-Benzodiazepines
- Ketamine
- Anabolic steroids
41
What is the history of heroin?
- Heroin is a synthetic opiate
- It is a chemical derivative of morphine, the principle ingredient of opium
- It is approximately 4 times more potent per gram of morphine
- First produced by CR Wright in 1874
- Produced by Bayer pharmaceuticals, Germany in 1897
- Hailed as "wonder drug"
42
What are some positive effects of opiates?
- initial euphoria
- removal of tension
- tranquility
- sense of control
- detachment from worries/fears
- analgesia
43
What are some negative effects of opiates?
- itching
- flushing
- myosis
- appetite suppression
- slurred speech
- slow gait
- depression
- constipation
44
What are some injection associated issues with relation to substance misuse?
- BBV
- DVT
- Abscesses
- Amputations
- Collapsed veins
45
What are some mental health problems associated with substance misuse?
- paranoia
- bipolar
- schizophrenia
- depression
- bulimia/anorexia
46
Approx how many deaths per year are from drug use in scotland?
approx 500
47
Approx how many deaths per year are from alcohol use in scotland?
5-25,000 deaths/year
48
Approx how many deaths per year are from smoking in scotland?
100,00 deaths per year
49
What other factors are associated with having poor mental health?
- Poor physical health
- Social injustice (poverty, deprivation, discrimination, inequality)
- Poor social relationships/network.
50
What is the definition of neurosis?
Contact retained with reality
51
What is the definition of psychosis?
Contact lost with reality
52
Give examples of functional mental health disorders that is associated with neurosis, this would be without delusions or hallucinations, behaviour is not without socially acceptable norms.
- anxiety
- phobic
- obsessional
- hypochondrial
- depressive
53
What are examples of mental health disorders that are associated with psychosis? Patients may show changes in personality, thought disorder and may exhibit strange behaviour. These patients are more likely to have difficulty in carrying out daily activities.
- schizophrenia
- bi-polar
54
What is schizophrenia?
- Most severe form of functional psychosis.
- thought and emotion disorder
- "fundamental and characteristic distortions of thinking and perception."
- Characteristic delusions - often bizarre
- auditory hallucinations - often threatening or derogatory
55
What are 3 types of eating disorders?
- PICA
- Bulimia nervosa
- Anorexia nervosa
56
What is anorexia?
Altered perception of body image. Dont eat- oral effects of malnutrition. Ulcers, dry mouth, infections, bleeding.
57
What is bulimia?
Normal weight - binge/vomit. "comfort eating" - stress reaction? Dental erosion and oseophageal structure.
58
What is PICA?
Persistent and compulsive cravings, non-foodstuffs, fracture teeth, denture, braces.
59
Name some organisations that you can refer patients to if looking for support on mental health disorders?
- Breathing space
- Samaritans
- GP
- Student Support Services
- NHS 24
- Mood cafe website
60
Whose role is it to assess suicide?
Very little in the way of guidance for dentists managing suicide risks.
Scottish Government 2018 "every life matters" states more needs to be done to make everyone more confident in asking questions and offering support." and "suicide needs to be everyones business, not just the frontline staff."
61
What are some high risk factors for suicide?
- Men have a higher suicide rate that women
- Below socioeconomic status
- 45-55 years old
Dynamic risk factors: relationships, job
Future risk factors: Pets that are old and unwell
62
What is the current problem with regards to assessing risk and preventing suicide?
- We arent very good at this and we arent getting any better
63
What are things you can do to assess a patients risk of suicide?
Ask questions such as:
"In the last 2 weeks have you had the thought that you would be better off dead or of hurting yourself in some way?"
"Have you made any plans about how you might hurt yourself?"
- Think about how you will manage this information before it gets disclosed
- Know of services in your local area that you can use to manage this.
64
What factors are typically associated with a patient requiring dental treatment in prison?
- High level of psychiatric illness
- High level of learning disability
- Addictions: Drugs, alcohol, tobacco
- Oral neglect
- History of self medication when in pain
- Attend through necessity rather than choice
- BBV
65
What factors are typically associated with a patient requiring dental treatment in prison?
- High level of psychiatric illness
- High level of learning disability
- Addictions: Drugs, alcohol, tobacco
- Oral neglect
- History of self medication when in pain
- Attend through necessity rather than choice
- BBV
66
What are some of the risk factors associated with people to become homeless?
- Males>Females more likely
- Relationship breakdown
- Prison
- Loss of employment
67
What is methadone?
Methadone Hydrochloride: Synthetic opiate analgesic
First made WW2, Germany
Trade name: Dolophine
White powder mixed with green syrup
68
How does methadone work? What is the physiology?
- Action on the CNS
- Oral administration
- Absorbed from the buccal mucosa and stomach
- Continuous occupancy of Mu opioid receptors
- Stabilizes neurochemistry, previously chaotic from repeated "highs" and "lows" of heroin use.
- Can lead to cessation of IV drug abuse- reduces risks of hep B, hep C and HIV
69
The sugar full methadone is what is normally prescribed for methadone users although there is a sugar free version, what are some reasons for this?
- Increased cost
- Poorer compliance with sugar free
70
How much sugar does the sugar full methadone have?
50% (35g)
71
What effects on teeth does the sugar full methadone have?
- High caries risk as 50% sugar content in syrup: often methadone "held" in the mouth to increase absorption in the buccal mucosa. Also an opiate analgesic therefore decreases salivary flow.
72
Methadone is not the only cause for caries therefore why do drug misusers have such poor oral health? Name as many factors as you can.
-Drug related factors: dry mouth/bruxism/habits/sugar cravings/sugar in medication
- History of non-attendance at GDP
- Self medicating when in pain
- Poor knowledge of oral health
- Heavy smoking
- Heavy alcohol use
73
What are some oral effects for patient taking amphetamines?
- Xerostomia therefore increased caries and perio disease
- Bruxism, grinding therefore TMD
- Attrition/erosion
74
What are some oral effects for patient taking ecstasy?
- Bruxism, grinding therefore TMD
- Occlusal wear on posterior teeth
- Increased intake of fizzy drinks
- xerostomia
- attrition and erosion
- mucosal burns
75
What are some oral and general effects for patient taking cocaine?
- Xerostomia therefore increased risk of perio and caries
- Caries in unusual surfaces
- Bruxism and TMD
- Erosion
- Gingival and tongue erosions
- Ulceration of palate
- Cluster headaches may mimic atypical facial pain
76
What are some oral and general effects for patient taking heroin?
- Oral effects depend on the route of administration
- No specific related oral findings
- General oral neglect
- Advanced circumferential caries
- Advanced periodontal disease
- Thrombocytopenia
77
What are some oral and general effects for patient taking cannabis?
- Decreased respiratory rate
- Impaired memory
- ? Consent
- Soft tissue disease
- Increased heart rate following adrenaline of local anaesthetic
78
What frequent behavioural habits to patients who are substance misusers have when attending the dentist?
- Poor attenders
- Poor time keepers
- Have short attention span
- Lack understanding
79
What considerations should you have when giving local anaesthetic to patients who have recently used cannabis or other stimulants with LA containing adrenaline?
Increased risk of tachycardia following recent use of cannabis or stimulants with LA containing adrenaline
80
What considerations should you have when planning for sedation/GA in patients with substance misuse?
- Sedation should be used with caution
- Potential damage for the heart, liver and kidneys
- Referral for treatment in hospital setting
- GA might not be feasible
- Resistance to GA
- IV access more difficult?
81
What sort of expectations are associated with patients with substance misuse?
Unrealistic expectations
82
What should you consider when prescribing for patients with substance misuse?
- Patients already taking multiple prescribed drugs
- Interactions such as disulfiram with alcohol
- Patients may seek unnecessary prescribed drugs from the dentist
83
How and what oral advice would you give to patients with substance misuse?
Keep it simple:
E.g brush teeth twice per day am and pm
Decrease number and frequency with sugars
Limit number of snacks per day
Importance of regular dental check ups
84
What specific advice should you give to a patient taking methadone?
- Drink methadone through a straw
- Try to take near a mealtime
- Swallow it immediately dont hold in their mouth
- Rinse with water afterwards
- Chew sugar free chewing gum to increase saliva
- Brush teeth BEFORE taking it or leave it for a few hours after
85
Name 3 barriers to patient care.
- Attitudes to oral health
- Attitudes to patient group
- Lack of knowledge
86
What is the definition of conscious sedation?
A technique in which the drug or drugs produces a state of depression of the central nervous system enabling treatment to be carried out, but during which verbal contact with the patient is maintained throughout the period of sedation. The drugs and techniques used to provide conscious sedation for dental treatment should carry a margin of safety wide enough to render loss of consciousness unlikely.
87
What clinical effects does conscious sedation have on the patient?
- Anxiolytic
- Anticonvulsant
- Slight sedation
- Reduced attention
- Amnesia
- Intense sedation
- Muscle relaxant
88
What are 3 types of conscious sedation?
- Oral sedation
- Inhalation sedation
- Intravenous sedation
89
List the things you would assess at the assessment for conscious sedation.
- Thorough MH taken
- Thorough social history taken
- Airway assessment- neck size/posture/Mallampati score
- Height
- Weight
- BMI
- Heart rate
- BP
- SpO2
- consider treatment required
- consider levels of anxiety
- consider social circumstances (IV requires escort)
90
Describe what inhalation sedation is.
Use of nitrous oxide and oxygen, delivered as a gas via nose piece mask. "Mild sedation" therefore for mild anxiety. Success in (some) children and adults however must have the ability to breathe through their nose. Has anxiolytic effects and analgesic effects. Post hypnotic suggestion.
91
What do we know about nitrous oxide?
- Inhaled gas
- Sweet smelling
- Colourless
- Heavy
- Sometimes known as "laughing gas"
- "Entonox"
92
What are the properties of nitrous oxide?
- Rapid onset of action 3-5 minutes
- Crosses the blood brain barrier rapidly
- Elimination also rapid
- No significant metabolism by kidneys or liver
- Not stored in the tissues
- No hangover effect
93
What are some signs of overdose with inhalation sedation?
- Nausea
- Headache
- Vomiting
- Diffusion hypoxia
94
What would you do to manage if a patient has signs of overdose with inhalation sedation?
- Reduce dose
- O2 flush
95
What is diffusion hypoxia?
When nitrous oxide is discontinued, it leaves the blood more quickly than nitrogen from air is absorbed. Can lead to dilution of oxygen in the lungs which can lead to hypoxia.
96
What should you do at the end of dental treatment to prevent diffusion hypoxia in IHS?
Administer 100% oxygen after cessation of nitrous oxide for 5 minutes.
97
Name 4 indications for IHS.
- Mild anxiety
- Needle phobic patients
- Patients not suitable for IV/GA
- Straightforward dental treatment
98
Name 5 considerations that would be required when considering IHS.
- Able to cooperate?
- Age
- Learning difficulty/ Cognitive impairment
- Ability to tolerate mask
- Mask may impede on anterior teeth
99
Name 7 contra-indications for IHS.
1. COPD
2. Recent eye or ear surgery
3. Mask intolerance
4. Pregnancy*
5. Vit B12 deficiency
6. Methotrexate interaction - poss drug holiday?
7. Chemotherapy interaction
100
Name the equipment used in IHS.
- RA machine
- Gas cylinders for piped gases
- Scavenging
- monitoring for staff eg heart rate etc
101
Describe what IV sedation is.
Delivered as an injection. Most commonly midazolam. Used for mild-moderate anxiety. Need to cannulate patients. Need for escort. Patients are required to "follow rules". Amnesia is common. Flumazenil must be present as a reversal agent.
102
What are the indications for IV sedations? Name 4.
1. Dental anxiety/phobia
2. Medically suitable
3. Social History
4. Unpleasant procedure
103
Name 5 contra-indications for IV sedation.
1. Needle phobia
2. Medical reasons
3. Social reasons
4. Pregnancy
5. Poor venous access
104
State all the equipment required to carry out IV sedation.
- Midazolam
- Flumazenil
- Labels for syringes
- Saline
- Pulse oximeter
- BP cuff and machine
- Tourniquet
105
What are things to be aware of with the patient in regard to measuring oxygen with pulse oximeters.
- Nail polish/acrylic gels
- Finger tapping/playing with pulse oximeter
- Breath holding
- Cold hands - warm water/gloves/layer up with clothing
106
What are 4 signs of IV overdose?
- Loss of protective reflexes
- Decreased respiration
- Loss of consciousness
- Decreased heart rate
107
What type of drug is flumazenil and when should you not give this to a patient if required.
- Benzodiazepine
- Should not give this to a patient if they have a benzo allergy.
108
Describe what oral sedation is.
Delivered as a drink, usually midazolam. Less common technique than IV or IHS. Not the same as a pre-med. Must still cannulate for safety (rescue/reversal). Proficient in IV technique.
109
Give a definition of a premedication.
1. Preliminary administration of a drug preceding a diagnostic/therapeutic, or surgical procedure, as an antibiotic or anti-anxiety agent.
2. A drug administered for such a purpose.
110
What instructions would you give to a patient where you are prescribing diazepam as pre-medication for dental treatment?
- 5mg-10mg diazepam prescribed
- Take last thing at night on the evening before the appointment
- On wakening on the morning of the appointment
- Prescribe only what is required
111
What doses are available in diazepam and what drug interactions does it have?
Antibacterials: isoniazid inhibits metabolism. Rifampicin increases metabolism.
Antivirals: Ritonavir
Proton Pump inhibitors: Omeprazole
112
Name some indications for prescribing diazepam to a patient.
- Very anxious patients, may aid them attending the surgery or sleeping the night before.
- Patients when sedation is contra-indicated: for medical reasons, inability to get venous access (IV sedation), inability to breath through nose (IHS).
- To "take the edge off" for complex procedures.
113
Name the contra-indications/cautions for prescribing diazepam to a patient.
Contra-indications: Hepatic impairment, renal impairment, pregnancy, breast feeding.
Cautions: Avoid prolonged use, reduce dose in debilitated patients, reduce dose in elderly, respiratory disease, patient compliance (taken at wrong time).
114
Name 4 benzodiazepine drugs and what there function is.
1. Midazolam: conscious sedation
2. Flumazenil: reversal agent
3. Diazepam: pre-med
4. Temazepam: Alterantive pre-med
115
What are all the clinical effects of benzodiazepines?
1. Anxiolytic: low doses, can be subtle, not analgesic
2. Anticonvulsant: prevent and terminate convulsant
3. Sedation: slight at low doses, intense at higher doses, decreased response to constant stimulus, reduced attention, will lead to sleep if left un-stimulated, dis-inhibition.
4. Amnesia: most intense with IV, anterograde amnesia, intense for the first 20/30 mins, variable duration but up to several hours, especially good with midazolam.
5. Muscle relaxant: central effect, depression of spinal reflex activity, partly responsible for respiratory depression
6. Anaesthesia
116
Name some short term side effects of benzodiazepines.
- drowsiness
- dizziness
- reduced concentration and coordination
- hypotension
- respiratory depression
- sexual fantasy
117
Name some long term effects of benzodiazepines.
- tolerance
- dependence
- withdrawal symptoms
118
Give a definition of general anaesthetic.
A state of controlled unconsciousness, affecting the whole body, so the patient does not move or feel pain, with loss of protected reflexes. An anaesthetist uses a combination of medicines to allow medical procedures to be carried out, that would otherwise be intolerable to the patient.
119
Name 6 indications for general anaesthetics.
1. Length or complex procedures
2. Very anxious/dental phobic patients who are unable to tolerate/co-operate with treatment under other modalities e.g LA, oral, IV or IHS.
3. Patients with a profound learning disability
4. Multiple extractions in multiple quadrants
5. Severe trauma or acute dental infection
6. Cases where IHS or IV sedation is contra-indicated
120
Name 4 advantages of using GA
1. Patient co-operation not required
2. Patient unaware of the procedure taking place
3. Significant amount of treatment can be carried out in one attendance
4. May be able to co-ordinate interventions with other specialities.
121
What are the disadvantages/limitations of GA?
- Pre-operative assessment medical and dental needed
- Need careful treatment planning/ all work to be done in one visit
- Treatment often has to be more radical to be done in one visit
- "Open" consent often needed as cannot change the treatment plan half way through therefore discuss further extractions of teeth.
- Does not help the patient get over their fear/confidence
- Cost?
- Pre-op fasting
- Risk of morbidity
122
Name the sedation standards and guidelines to refer to.
- IACSDS (intercollegiate advisory committee for sedation in dentistry standards)
- SDCEP (conscious sedation in dentistry)
123
Describe the sedation process.
appropriate referral, virtual or telephone consultation, in person assessment, baseline monitoring, identify suitable technique, agree treatment plan, start consent process, list for treatment under sedation.
124
What are the different levels of sedation?
- Minimal sedation: Anxiolysis, retains patient's ability to respond normally to stimulation and verbal command
- Moderate sedation: Conscious sedation, depression of consciousness, patients respond purposefully to verbal commands
- Deep sedation: nearly unconscious, only has purposeful response to repeated and painful stimuli
- General anaesthetic: completely unconscious, does not respond to any level of pain. The patient will require breathing assistance and CV function may be impaired.
125
What are the requirements for an ideal sedative?
Safety: Wide margin of safety, no side effects, reversible
Simplicity: Easy to deliver and titrate dose to response
Action: Rapid onset and recovery
Analgesia: Good control of pain
Amenesia: reduced memory of treatment
Acceptability: To patient
Compatibility: with other systemic drugs
Cost
126
What happens are IV injection physiologically?
- Rapid rise in plasma level
- Drug passes through RHS of heart, pulmonary circulation and the left side of heart
- Goes to brain via arterial system
- Effects start once crossed blood brain barrier
- Hand-heart-brain circulation time is approx 25 seconds
127
How does the patient recover from sedation physiologically?
- Redistribution of the drug from CNS into body fat
- Uptake and metabolism of the drug by liver and elimination by the kidneys
128
What occurs first, redistribution or elimination of a sedative drug?
(1) - Redistribution is the initial recovery from sedation, this is the alpha half life where this is the time taken for the serum concentration to drop by 50%.
(2) - Elimination is the beta half life, the time taken to remove half the drug from the body.
129
Pharmacodynamically benzodiazepines are all the same. What are the differences due to?
- Affinity for receptors (potency)
- Half life
- Active metabolites
130
Describe the mechanism of action of benzodiazepines?
- Gamma aminobutyric acid
- Endogenous inhibitory neurotransmitter
- GABA controls the synaptic flow of chloride ions
- Activation of the benzodiazepine receptors enhances the flow of the chloride ions
- Chloride ions enter the cell making the resting potential more negative
- This makes it even more difficult to fire an action potential so reducing polysynaptic transmission and depressing the uptake of sensory information
131
Why is diazepam no longer used for IV sedation and what is its half life?
Half Life: 30 hours
No longer used because the organic solvent cause vein damage: pain, thromboplebitis, skin ulceration
132
What is diazemuls?
Injectable brand of diazepam
Long half life 43 hours
Non-irritant to veins
Long recovery period and possibility of rebound sedation meaning not well suited to dental procedures
133
Is midazolam water soluble? What is its pH?
Yes pH<4
134
How should midazolam be administered in adults ?
By slow IV injection: Initially 2-2.5mg, to be administered 5-10 minutes before procedure at a rate of approximately 2mg/minute, increased in steps of 1mg if required, usual total dose is 3-3.3mg. Maximum 7.5mg per course - usually 10mg maximum in clinic.
135
How should midazolam be administered in the elderly?
Initially 0.5-1mg to be administered 5-10 minutes before procedure at a rate of approx 2mg/min, increase in steps of 0.5-1mg if required; maximum 3.5mg per course
136
How does midazolam work physiologically once injected IV?
Once in the bloodstream it becomes lipid soluble at physiological pH
Can then readily penetrate the blood brain barrier
137
What is the elimination half life of midazolam?
1.9 hours +/- 0.9 hours
138
How long would a patient be sedated for after administration?
20-30 mins following with a period of relaxation after which may last another hour or so
139
How is midazolam excreted in the body?
Rapidly metabolised in the liver but some metabolism takes place in the bowel.
Produces an active metabolite called alpha-hydroxymidazolam which is has a short half life of 1.25 hours
140
Is midazolam or diazepam faster acting?
Midazolam
141
Is midazolam or dizapam more potent?
Midazolam - 2.5 more times
