Prescribing in OS Flashcards
what are the basic prescribing principles ?
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Date
Patient Details (inc D.O.B.)
Practice Details
Drug Name
Dose
Frequency
Quantity to be supplied
Sign
Print Name
what are some common abbreviations ?
- cap capsule
- tabs tablets
- mg milligrams
- mcg micrograms
- ml millilitres
- mitte send
- nocte at night
- mane morning
- bid/bd twice a day
- tid/tds three times day
- qid/qds four times day
- prn as needed/required
- stat immediately
what do we do if a pt come back with and adverse rxn?
- report on mrha
- and give medical advice
how can we check if there are any drug interactions ?
check BNF
what aer some of the most common things we prescribe ?
analgesics
antbiotics
anti fungals
anti virals
sometimes
fluoride
saliva
emergency drugs
sedative drugs/ anxiolysis
how do give advice with analgesics ?
we usually go up to step 1 or 2
- anything above step 2 we need to identify why ie, not taking it right, deteriorated ? dose? peak? inactivation ? contraindications?
what is paracetamol? what level according to WHO? mechanism of action? contraindications?
-Pyrerxia = reduces temp (antipyretic)
- reduces Pain (analgesic)
- WHO Level 1
- Precise mode of action is unclear
- Weak inhibitor of COX-1 and COX-2
- Weak Anti-inflammatory activity
- Oral or Intra-venous
- 500mg / 1g QDS
- Max dose 4 in 24 hours – care with OD (2-3 x dose) – Liver Damage
30-60 min peak plasma orally
- Bound to plasma proteins
- Drug inactivated in the liver – conjugated to give glucuronide or sulphate.
- Allergy
-Liver damage
OTC
what is ibuprofen ? uses? WHO level? mechanism of action? dose? contraindications ?
- inflammation
-Pain – particularly musculoskeletal, rheumatic and joint problems - WHO Level 1 +/- in combination with Paracetamol
More than 50 different types of NSAIDS on the market (Naproxen, Diclofenac, Ketoprofen, Mefanamic Acid etc) - Proprionic acid derviative, blocks synthesis of T-A2 in platelets from arachidonic acid
Binds to and inhibits COX (unselective)
Competitive inhibition - Oral
- 400mg QDS
With or just after food - Plasma ½ life 2 hours
Metabolised and biotransformed in the liver
Renal elimination – completely in 24 hours after the last dose - Elimination is not impaired by age or renal impairment
- Allergy
- GI disturbances
- Renal failure
- Asthma / COPD
OTC
what is cocodomal ? WHO level? mechanism ? dose? contraindications ?
codeine phosphate+ paracetamol
Level 2/3 WHO analgesic ladder
Compound analgesia
Opioid based medication, reduces endorphins. Combine with gamma receptor in the brain.
Blocks pain tramission. Prodrug.
Two doses
8/500 available OTC equates to 8mg codeine and 500mg paracetamol – Dose is TT QDS
30/500 available POM equates to 30mg codeine and 500mg paracetamol – Dose is TT QDS
Well absorbed orally.
Undergoes considerable first-pass metabolism and therefore less potent orally compared to IV opioids.
Asthma, Drug dependence history, liver
Side effects are constipation, N&V and in larger doses respiratory depression
- paracetamol during day and then take cocodomal at night to prevent tiredness during day
OTC/ POM
how do we treat an infection?
- want to remove the cause of the infection
- we may give antibiotic for the infection or give prophylaxis to prevent the post op infection
what do we do when a pt comes in with an abbess?
- prescribe empirically
- but before you prescribe send a sample of the pus to lab
what are different ways in which we can treat an infection?
- incise and drain
- extraction
- if there is evidence of systemic or spreading infection ie. lymphadenopathy, truisms, pyrexia and tachycardia = antibiotics
mode of action of antibiotics ?
when do we prescribe antibiotics ?
what is c diff?
- loads of antibiotics can cause disruption to gut flora and c diff then proliferates
- which causes profuse diarrhoea and pseudomembranous colitis (yellow white plaques on colon)
list the common antibiotics we prescribe in dent?
Penicillin
Cephalosporin / Beta-lactams (only prescribe in hospital)
Erythromycin
Clindamycin
Tetracyclines
Metronidazole
why do we prefer to prescribe narrow spectrum?
don’t want to suppress normal bugs which might cause c. diff
what is phenoxymethylpenicillin ? (penicillin v) use? mech of action? dose? contraindications ?
- narrow spec
- Acute dental infections – purulent infection
Post-surgical infection
Pericoronitis
Salivary gland infections
Bactericidal
Inhibits cell wall synthesis by inactivating the enzyme transpeptidase
Effective against alpha haemoluytic stpre and penicillinase –ve staph; aerobi G+ve and some anaerobic G-ve organisms.
500mg QDS
‘erratic’ absoprtion from GI.
Virtually non-toxic
Allergy
what is amoxicillin ? spec? uses? mech of action? dose? contraindications?
broad spec
Acute dental infections – purulent infection
Post-surgical infection
Pericoronitis
Salivary gland infections
Bactericidal and broader than Pen V
Inhibits cell wall synthesis by inactivating the enzyme transpeptidase
Effective against alpha haemoluytic stpre and penicillinase –ve staph; aerobi G+ve and some anaerobic G-ve organisms.
500mg TDS
P
‘erratic’ absoprtion from GI.
Virtually non-toxic
Issue with susceptibility to beta-lactamase (ref C—Amoxiclav)
Higher incidence of rashes.
Should not be given if pt with Infectious Mononucelosis or Leukaemia – rashes
Allergy
See above
N&V can be common
what is flucloxacilin? uses? spec? resistance? dose? contraindications ?
Confirmed skin infections
Narrow spectrum antistaphylococcal peniciiln
Relatively resistance to beta-lactamase produced by Staphylococcus aureus.
500mg 6 hourly
Safe non-toxic even in high doses.
MRSA strains emergine widely – so some resistance issues.
Allergy
Diagnosis must be confirmed
eg of cephalosporins ?
All are beta-lactams similar to penicillin
Growing in production
Cefotaxime
Cefuroxime
Cephalexin
Cephradine
what are cephlasporins? uses? spectrum? dose? contraindications?
Few in dentistry
Used to be used as alterantive for Penciillin resistant patients
Phased out in dentistry, maybe in hospital if MC&S sensitive
Broad spectrum
Active against both G+ve and G-ve bacteria
Eg. Cefalexin 500mg TDS
~10% penicillin sensitive patients demonstrate cross-sensitivity
Allergic reactions (urticaria, rashes)
Nephrotoxicity
Oral bacteria inc streptococci can develop cross-resistance to both penicillin and cephalosporins
Allergy
Diagnosis must be confirmed
eg of macrolides?
All are beta-lactams similar to penicillin
Growing in production
Erythromycin
Clarithromycin
Azithromycin
Clindamycin
when do we use macrolides ?
alternative to penicillins for allergy
what is erythromycin ? uses? mechanism of action ? doses? contraindications ?
Second line in oral infections
As obligate anaerobes aren’t particularly sensitive
Bacteriostatic
250-500mg QDS
Similar to penicilllin – suitable as an alternative for penicillin allergy patients
Haemophilus influenzae, Bacteroides, Prevotella and Porphyromonas spp. are sensitive.
Active against beta-lactamase producing bacteria.
High doses can cause hepatotoxicity
what is clindamycin ? uses ? mechanism of action? dose? contraindications?
Second line in oral infections
As obligate anaerobes aren’t particularly sensitive
Inhibits protein synthesis by binding to bacterial ribosomes.
150mg QDS
Similar to erythromycin – suitable as an alternative for penicillin allergy patients
Haemophilus influenzae, Bacteroides, Prevotella and Porphyromonas spp. are sensitive.
Active against beta-lactamase producing bacteria.
Mild GI disturbances are common – diaorrhoea
Be aware of antibiotic associated colitis (pseudomembranous colitis). This can be fatal.
what are tetracyclines?
Previously a very common antibiotic
Broad spectrum of activity
Few side effects
Increase in bacterial resistance hence decrease in use
what is tetracycline? mechanism of action? dose? contraindications?
Some evidence for use in periodontis – localised aggresive
Bacteriostatic – inferfere with protein synthesis by binding to bacterial ribosomes
250mg TDS
Wide range of spectrum of activity against oral flora
Inc Actinomyces, Bacteroides.
Distributed widely in body tissues including bone and developing teeth.
Particularly concentrated in gingival fluid.
Absorption of the drug is reduced by anacids, calcium, iron and magnesium salts.
Avoid in children up to 8 years due to absorption into developing teeth, pregnancy, lactating women.
D&V sometimes after oral absorption due to disturbance in bowel flora.
Hepatotoxicity with high IV doses.
what is metronidazole? uses? dose? contraindications?
Effective against anaerobic infections
Acute necrotising ulcerative gingivitis (ANUG)
Bactericidal – converted by anaerobic bacteria into a reduced active metabolite which inhibits DNA synthesis.
200mg / 400mg TDS
All strict anaerobes
GI upset, sometimes a metallic taste in the mouth.
Interferes with Alcohol metabolism – and if taken together can cause disulfiram reaction
Potentiates anticoagulants
Long term can cause peripheral neuropathy
eg of antifungals ?
Polyenes
Nystatin / Amphotericin
Azoles
Miconazole / Fluconazole
what is nystatin ? uses? mechsanism? dose? side effects ?
Fungal infections of skin / GI Tract
Superficial fungal infections
Not suitable for chronic hyperplastic candidiasis
Fungistatic and fungicidal.
DIsruption of the fungal cell membrane.
Oral suspension 100,000 units/ml
1ml QDS after food for 1/52
Polyene macrolide
Limited abosprtion from mucous membranes or skin
N&V & diarrhoea are rare
No adverse effects reported with topical route
what is miconazole ? uses? mechanism? dose? contraindications
Dual action against yeast and staphylococci – sometimes useful for Angular Cheilitis
Fungicidal and bacteriostatic for some Grame+ve cocci (inc S. aureus).
Gel – 20mg/g (80g tubes)
Apply pea sized amount after food, QDS for 1/52
Synthetic antimycotic agents
Broad spectrum of activity
Block synthesis of ergosterol – altering fluidity of membrane and enymes.
Also inhibits the transformation of candidal yeast cells into hyphae
Anticoagulants and Statins – do not prescribe
what is fluconazole ? uses? dose ? mechanism ? contraindications? side effects ?
Triazole – popular as wide spectrum of activity on yeasts and other fungi.
Specifically used to prevent Candida infection in HIV-infected individuals.
Generally a 2nd line
As miconazole
50mg OD for 1/52
As miconazole
Anticoagulants and Statins – do not prescribe
Minor GI irritation, allergic rash, elevated LFTs
eg of antivirals ?
aciclovir
antiviral agents ?
- Fewer on the market cf Antibacterial
- Challenges to interefere with viral activity within cell
- Best given early
- Incubation often short with viral infections
- Laboratory testing takes time
- Viruses may be latent in cells
what is acyclovir? uses? mechanism? dose? side effects ?
Primary and secondary herpetic stomatitis
Herpes labialis
Blocks viral DNA production
Topical 5% cream
Start in ‘prodromal phase’
Oral tablets for severe infections 200mg 5 x per day for 5/7
As above
Nephrotoxicity with other drugs – check BNF
what are some problems here?
- erthyma
- worrying as spread past midline and near eyes
- can’t see lower border of mandible
- in submandibular and submental region
- we need to ask if he can swallow, breathing ok? where is tongue? is it elevated?
- need to triage quick
- to describe this: bilateral submandibular swelling with orbital involvement
- don’t lie flat as tongue will obstruct airway
problems here?
- angular chelitis
- proliferation of staph in this area due to face height can be due to no teeth, poor dentures so teeth don’t close
- change anti fungal or bacterial
- we give miconazole cream 7-10 and sodium fusidate 10/7
what is this ?
Metronidazole 400mg TDS 3-5/7
Local measures
Asessment + diganosis confirmed
Amoxicillin 500mg TDS 3-5/7
what is this and what do we do ?
Local measures
Hydration, CXD m/w, soft diet, analgesia
Asessment + diganosis confirmed
Aciclovir 200mg 5 x day
what is this and how do we Treat?
what is this and how do we treat ?
Varicella Zoster (Shingles)
Aciclovir 800mg 5 x day
Asessment + diganosis confirmed
Medical assessment