principles of prescribing Flashcards
which three groups of patients do you need to be cautious with when prescribing
- children
- pregnancy/lactation
- elderly
what do training and healthcare professionals place a greater emphasis on
diagnostic rather than therapeutic skills
what does the choice of treatment depend on
the patient
when does prescribing practice need to be adapted
as the patient demographics vary e.g. young, elderly and other ‘at risk’ groups
what 4 things do poor prescribing habits lead to
- ineffective and unsafe treatment
- prolongation of illness
- distress and harm to the patient
- higher costs of treatment
list the 5 stages in the process of rationale prescribing
- specify the therapeutic objective
- make an inventory of possible treatments
- choose a treatment (taking into account efficacy, safety suitability and cost)
- provide patient with clear information and instructions
- monitor the effectiveness of the treatment (if therapeutic objective is being achieved)
this is what we hope to achieve behind prescribing this particular drug
what does someone being under the age of 12 constitute
a child, so be cautious with choice of drug
what is the first step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction
define the clinical problem
how do you define the clinical problem of 10 year old child who visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction
give 4 actions
- exclude more serious causes of red eye
- are the signs and symptoms suggestive of seasonal allergic conjunctivitis
- assess the severity of the problem
- are there any associated symptoms
why is it important to find out if there are any associated symptoms with 10 year old child who visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction
with seasonal allergic conjunctivitis, are the eye symptoms associated with nasal symptoms
important because if our therapeutic objective is to treat the eye symptoms, we might control the eye symptoms but we won’t be doing anything for the nasal symptoms
what is the second step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, once you have defined the clinical problem
specify the therapeutic objective
how do you specify the therapeutic objective of 10 year old child who visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction and why
you alleviate the symptoms
because this is the main therapeutic objective and you want to improve the appearance of the eye by controlling the disease
what is the third step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, once you have decided that you want to specify the therapeutic objective
you find an inventory of possible treatments
what is the recommended inventory of possible treatments for a 10 year old child who visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, who has been defined as having seasonal allergic conjunctivitis
- identify the allergens and avoid if possible (so think about the non pharmacological options available to us)
- recommend antihistamine or mast-cell stabiliser eye drops
which possible treatment of seasonal allergic conjunctivitis provides a more rapid relief of symptoms
topical anti histamine
which topical eye drop may be considered first line for prophylaxis
mast cell stabiliser
how does a mast cell stabiliser work
- it takes several weeks to act
- it reduces degranulation of the mast cells
what will you advise to you px when prescribing them with a mast cell stabiliser for their seasonal allergic conjunctivitis
they may not get relief for the first few weeks, but eventually they will
when will you consider oral antihistamines or intranasal corticosteroids for a patient who suffers from seasonal allergic conjunctivitis
if there are associated symptoms of: rhinorrhoea, sneezing or nasal irritation
as well as taking therapeutic agents, what else can you advise your patient to do if they have seasonal allergic conjunctivitis
a cold compress with a flannel and cold water as this may be soothing
what is the fourth step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, once you have found an inventory of possible treatments
you choose a treatment
what is there limited evidence on about topical antihistamines
that they are quicker to act than mast cell stabilisers
what are anti-allergy drugs not associated with
any significant safety concerns
what should the choice of topical treatment be made according to, when choosing between anti histamines and mast cell stabilisers, to treat seasonal allergic conjunctivitis
the needs and preference of the individual you are treating
what choice of drug is recommended if a patient has intermittent symptoms of seasonal allergic conjunctivitis
topical anti-histamine
when would you recommend a topical mast cell stabiliser to a patient with seasonal allergic conjunctivitis be the first treatment choice and give 3 reasons why
if prevention of the allergy over a longer period is required, because:
- it gives rapid relief of allergic conjunctivitis (not as rapid as topical anti histamines)
- it is well tolerated
- theres few adverse effects
as an optometrists, how will you go about supplying both a topical anti histamine and topical mast cell stabiliser combined, in order to treat someone with seasonal allergic conjunctivitis
- refer to an independent prescribing optometrist
or - refer to the GP to get a prescription for the particular drug
what should an individual therapeutic product be selected based upon
their convenience of use and cost
what has the combination of anti histamine and mast cell stabiliser proven to be and give an example of one
more cost effective
e.g. olopatadine
what should you consider over topical anti histamines if nasal symptoms are also present in addition to seasonal allergic conjunctivitis
systemin anti histamines
what do you need to consider when choosing a treatment for a 10 y/o child complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction and a diagnosis of seasonal allergic conjunctivitis
whether the drugs of choice are licensed for a 10 year old
children and particularly ________ differ in their ___________ to ________
children and particularly neonates differ in their response to drugs
what is increased with neonates and drugs
the risk of toxicity
how is the risk of toxicity of drugs increased in neonates
by reduced drug clearance and difference target organ sensitivity
drugs are ____ extensively _________ in children
drugs are not extensively tested in children
what may not be available to ensure precise dosing for children
suitability formulations
how will you check suitability for use of a drug in children
by referring to the SPC or other reliable sources of information
there may not be a licence formulation for children under 12 years old
what are the two top general topical anti histamines available OTC and what are the age groups
- antazoline > 12 years
- azelastine > 4 years SAC, > 12 years PAC
which three topical anti histamines are only available on prescription and what are their age groups
- emedastine > 3 years
- ketotifen > 3 years
- lodoxamide > 4 years
name a topical mast cell stabiliser available OTC and what is the age group
- nedocromil sodium > 6 years
name a combines topical mast cell stabiliser and anti histamine and what is the age group
- olopatadine > 3 years
why is antazoline topical antihistamine only available to > 12 year old children
because it contains vasoconstrictor and that is the contraindicative part
name an oral anti histamine that you will not give to a 10 year old child, what is the dose and instructions of this medication and what is the minimum age allowed to take it
- cetirazine 10mg, zirtec (P)
- 10mg
- 1x tablet taken daily
- > 12 years old
name an oral anti histamine that you will give to a 10 year old child, what is the dose and instructions of this medication and what is the minimum age allowed to take it
- cetirazine 5mg, zirtec syrup (P)
- 5mg
- 1x 5ml taken daily
- > 2 years old
this is a child specific formulation
what is the fifth step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, are diagnosed with seasonal allergic conjunctivitis and have chosen a treatment
you provide clear instructions
what clear instructions on a drug will your provide to a patient with seasonal allergic conjunctivitis
- instructions on the use of drops (make sure they know how to put it in)
- if mast cell stabiliser, advise that may take 3 weeks for maximal effect
what is the sixth step to take if a 10 year old child visits you complaining of itching epiphora of a 2 week duration, with signs of lid oedema, conjunctival oedema, redness of the tarsal conjunctiva with a papillary reaction, are diagnosed with seasonal allergic conjunctivitis and have provided clear instructions on the drug
monitor
what will you monitor for after supplying a patient with topical anti histamines or mast cell stabilisers to treat seasonal allergic conjunctivitis
- relief of symptoms?
- compliance?
- adverse reactions?
why should medication be used with caution in pregnancy or when breast feeding
as drugs have the potential to cause harm by crossing the placenta or entering breast milk
what 2 possible things can happen and what implications can this have, once a drug is taken (even if topically) and is in the plasma as it goes through systemic absorption
- drug can cross a placental barrier and influence the developing foetus
or - drug can pass the plasma and into the breast milk and therefore get passed to the child
what should be avoided and considered when prescribing in pregnancy
- avoid unnecessary drug use
- consider noon-drug therapy
what must you assess when prescribing in pregnancy
the benefits/risk ratio for both mother and developing baby
why must you avoid ALL drugs in the 1st trimester of pregnancy wherever possible
this is the greatest risk for teratogenesis which is the 3-11 weeks of pregnancy
this is the period of organ development
why must you avoid drugs in the 2nd and 3rd trimesters of pregnancy
they may affect the growth of the foetus or functional development or have a toxic effect of foetal tissue
which type of medicines carry greatest risk in pregnancy/lactation
systemic
what do topical medicines vary in during pregnancy/lactation
vary in their potential risk
which medication has safety not been established during pregnancy or is not know whether its secreted into breast milk
the OTC anti histamine antazoline 0.5%
which is the most appropriate therapy for giant papillary conjunctivitis exasperated by hay fever for a pregnant or lactating patient
sodium cromoglycate 2%
what should be avoided and considered when prescribing for breast feeding mothers
unnecessary drug use and consider non drug treatments first
what should you assess when prescribing for breast feeding mothers
the benefit/risk ratio for both mother and infant
which type of drugs should you avoid when prescribing for breast feeding mothers
drugs know to cause serious toxicity in adults or children
if the drug is toxic in adults, it will be even more toxic in children
which type of drugs should you use if you decide to and why when prescribing for breast feeding mothers
use older drugs first-line as these will have a more detailed safety history; use the lowest effective dose
what type of drugs do not generally pose a hazard for breast feeding mothers and why
drugs licensed for use in infants
why are neonates and particularly premature infants at greater risk from exposure to drugs via breast milk
because of the immature/underdeveloped excretory functions and the consequent risk of drug accumulation
why may multiple drug regimes pose an increased risk to breastfeeding mothers
as adverse effects may be additive
what should you do for infants exposed to drugs via breast milk and why
they should be monitored
for unusual signs and symptoms
what is there a reduction in with age
renal drug clearance
which substances are a problem for drugs hat are excreted unchanged by the kidney and have a narrow therapeutic index with the elderly
digoxin or lithium
which diseases worsen renal function in the elderly
diabetes and heart failure
in general, older people have an increased ___________ to drugs, particularly those acting on the __________ __________ system
in general, older people have an increased sensitivity to drugs, particularly those acting on the central nervous system
what 2 things may frail elderly people have difficulty in and what can be done to help them with this
- difficulty swallowing tablets or using eye drops
- consider using compliance aids for eyedrops
