W12 41 the role and efficacy of drugs

Question 1

What are the pharmacological agents are for different categories of treatment?

Answer 1

Cure diseases - eg antibiotics in dental infection
Treat risk factors for disease - eg sodium fluoride in caries prone patients
Alleviate symptoms - analgesia in dental pain
Replace deficiencies - ascorbic acid in scurvy, insulin in diabetes

Question 2

What are other reasons for prescribing?

Answer 2

To buy time
To monitor a patients condition
For a therapeutic trial to assist diagnosis
Responding to patient expectations

Question 3

What is the difference between pharmacokinetics and pharmacodynamics?

Answer 3

If a drug is taken and it achieves plasma concentration, this is pharmacokinetics.
If it is in the plasma and effecting receptors in the tissue, this is pharmacodynamics.

Question 4

What are the 6/7 ‘rights’ of prescribing?

Answer 4

Right dose
of the Right drug
for the Right diagnosis
to the Right patient
at the Right time and
via the Right route
(patient has the Right to refuse)

Question 5

What is the balance in rational prescribing?

Answer 5

Maximising effectiveness and minimising harms
(but also minimising cost and relieving NHS pressure and respecting patient choice)

Question 6

What should you know about every drug?

Answer 6

Indications, cautions, contraindications, side-effects, dose, interactions, where it goes - the route

Question 7

Should you prescribe generic medicines or branded medicines?

Answer 7

Generic medicines mostly
Generic - as the approved (generic) name. Pharmacist will dispense the most cost-effective brand
Branded - generally not advised to prescribe by brand, as pharmacist can only dispense the named brand. Usually less cost effective.

Question 8

What are the special groups that should be considered with respect to drug administration?

Answer 8

Young / children
Pregnancy, fetotoxicity and teratogenicity
Liver disease
Renal impairment

Question 9

What are the breakdowns of age groups?

Answer 9

0-30days - newborn
30days-1 year - infant
1-12 years - child
12-18years - adolescent

Question 10

How should dose be worked out for youngers?

Answer 10

Dose needs to be worked out per Kg of body weight, or better for surface area.
Injections should be avoided if possible.

Question 11

What needs to be considered for children?

Answer 11

They are little!
Pharmacokinetic factors eg neonates may not have developed their excretory process
Check dose
Check form (liquids)
Drugs are dangerous
Special BNF for children

Question 12

What is teratogenesis and when should it be considered?

Answer 12

Teratogenesis - medicines that can cause problems
Consider prescribing and teratogenesis in all women of a fertile age - first trimester is when most organs of the baby is formed and development occurs!

Question 13

What tips are there for prescribing in pregnancy?

Answer 13

Avoid prescribing if possible
Use old and tried drugs if needed - never new
BNF indicates what is dangerous but does not state what is safe

Question 14

Should you prescribe during breastfeeding?

Answer 14

Evidence is lacking. Choose treatment with care. Check how long breastfeeding for, eg can be long 12-18months.

Question 15

What liver diseases might cause problems with drugs?

Answer 15

Jaundice, ascites, evidence of encephalopathy

Question 16

What problems could there be in patients with liver disease?

Answer 16

Clotting abnormalities
Metabolism of drugs impaired
Effects of some sedatives potentially fatal

Question 17

Is prescribing worse for acute or chronic liver failure?

Answer 17

Acute liver failure - prescribing is potentially very dangerous. Risk of hepatic encephalopathy. Risk of bleeding. Metabolism impaired. Glucose stores low. Avoid drugs toxic to the liver.
Chronic liver failure - much less serious but there is some impairment of metabolism

Question 18

What might occur in prescribing in renal impairment?

Answer 18

Failure to excrete a drug or its metabolites may lead to toxicity
eGFR - estimated glomerular filtration rate
Avoidance of problems by reducing dose or by using alternative drugs

Question 19

When is special care needed for the renal impaired?

Answer 19

Renal transplant patients
Immunosuppressed patients
Dialysis patients
?specialist referral

Question 20

What’s bad for prescribing in renal failure?

Answer 20

Aciclovir (beta otic ulceration)
Tetracyclines
Benzodiazepines (anxiolytics or sedative)
NSAIDs (can upset kidneys making mild renal failure worse)

Question 21

What should you do when prescribing in renal failure?

Answer 21

Avoid any drug that is nephrotoxic
Other drugs may require dose reduction

Question 22

Should you use dental sedation drugs in people with renal impairment?

Answer 22

Drugs used in dental sedation should be used with extreme care as a greater effect than normal may be produced

Question 23

What should you consider with interactions when prescribing?

Answer 23

All drugs can potentially interact
Certain drugs the potential is much higher than for others eg WARFARIN, IMMUNOSUPPRESSANTS

Question 24

What drug interactions should we be aware of?

Answer 24

Interaction of NSAIDs, carbamazepine, azole antifungals, metronidazole and macrolide antibiotics with warfarin
Incidence of myopathy after prescribing azoles and clarithromycine in those taking statins

Question 25

How might drugs interact?

Answer 25

Drugs interactions represent a change in either the magnitude or duration of action of one drug caused by the presence of a second. This may enhance or reduce the efficacy of one of both of the drugs or a new effect may appear which is not seen with either of the drugs alone. Interactions may be pharmokinetic or pharmacodynamic.