Therapeutics Dr Monem Alshok 12\4\2011
Lectures in Therapeutics :
Overview ,Prescription
Adverse Reaction ,Drugs Interaction
Prescription in special situations : Pregnancy , Breast Feeding , Elderly , Renal & Hepatic diseases.
Corticosteroids & Diuretics
Clinical Trials
Introduction to clinical Therapeutics: Prescription :
The administration of medicines is an event that requires professional judgement. Administration should be undertaken and recorded in a manner, which is clearly understood by the prescriber, nurse, pharmacist and other health care individuals involved in the patients care. Medicines should be prescribed only when they are necessary, and in all cases the benefit of administering the medicine should be considered in relation to the risk involved. This is particularly important during pregnancy when the risk to both mother and fetus must be considered . It is important to discuss treatment options carefully with the patient to ensure that the patient is content to take the medicine as prescribed . In particular, the patient should be helped to distinguish the side-effects of prescribed drugs from the effects of the medical disorder. When the beneficial effects of the medicine are likely to be delayed, the patient should be advised of this.
Goals in Clinical Therapeutics :
The goal is for you to acquire a general understanding about how drugs exert their therapeutic effect, and as importantly learn how to prescribe them safely and appropriately.The diseases and conditions to be treated .The evidence that a particular drug or therapy is effective. Whether benefits are on quality or quantity of life number needed to treat / risk reduction .The context in which drugs should be used (i.e. other effective drugs . The mechanism(s) of action precautions in use ,important contra-indications . Important adverse reactions likely benefits versus cost of treatment
Potential developments within the next 2-3 years
Good prescribing practice:
To be a good doctor, it is essential to understand and apply the principles of prescribing medicines. Therapeutics lies at the heart of medicine and is what doctors do on a daily basis. Therefore having a grasp of the concepts underlying good prescribing is mandatory in order to deliver the best possible care for patients. Conversely, bad prescribing and medication errors affect up to 17% of patients in the UK (some still prove fatal the cost is around £400 million annually) more importantly the associated harm to patients, is avoidable if medicines are prescribed appropriately.
Remember the “Golden Rule” of prescribing
if in doubt, check it out
Drug Indications: details of uses and licensed indications, Indication is the reasons for administering a medication or performing a treatment.
Cautions: details of precautions required (with cross reference to any appendices) and also any monitoring required.
COUNSELLING: verbal explanation to the patient of specific details of the drug treatment (e.g. posture when taking a medicine)
Contra-indications: details of any contra-indications to use of drug. A factor that prevents the use of a medication or treatment (eg. Allergies )
Side-effects: details of common and more serious side effects
Dose: dose and frequency of administration (max.dose); CHILD specific age group
By alternative route, dose and frequency
Pharmaceutical form, colour, coating, active ingredient and amount in dosage form, net price, pack size and ELDERLY details of dose for specific age
Points to remember when you write a prescription:
ALWAYS write legibly in ink or other indelible.
ALWAYS sign & date the prescription (it is a legal document!)
NEVER abbreviate drug names ,NEVER use proprietary names ,ALWAYS use generic names* PREFERABLY use plain English for dosing direction
Dose :The amount of a drug to be administered at one time
Mechanism of Action :How a drug works.
When you write the INDIVIDUAL DOSE:
for STRENGTHS >1g use grams e.g. 100 g
for STRENGTHS <1g use milligrams e.g. 100 mg
for STRENGTHS <1mg use micrograms e.g. 100 microgram (NEVER use µg )
AVOID unnecessary decimal points e.g. use 300 mg NOT 0.3 g
Effects: The desired result of administration of a medication
Side Effects: Effects that are not desired and that occur in addition to the desired therapeutic effects
Drug Names:
Broadly speaking, drugs have three different names.
1. The approved (non-proprietary) or generic name is what ought to be used if possible, unless a specific preparation of the drug is required ( diltiazem ).
2. The chemical name is seldom used in clinical practice 3.whereas the proprietary or brand name should be avoided as this can vary greatly, depending on where you are in the world. For example, acetylsalicylic acid (chemical name) is widely known as aspirin (approved name); in the UK, it is available as numerous branded formulations (eg. “Disprin” or “Anadin” etc), which may not be available or indeed recognized in other countries.
Prescribing abbreviations
Although directions for use should preferably be in English without abbreviation, it is recognized that some Latin abbreviations are used when prescribing drug timings:
ante cibum (before food) a.c.
bis die (twice daily) b.d.
omni die (once daily) o.d.
o.m. - omni mane (every morning)
o.n. - omni nocte (every night) p.c. - post cibum (after food)
p.r.n. - pro re nata (when required) nebulisation
q.d.s. - quater die sumendus (four times daily)
q.q.h. - quarta quaque hora(every four hours)
stat - immediately (NB. only by specialist) t.i.d. - ter in die (three times daily)
Prescribing Abbreviation Routes
N.G. via naso-gastric
IM intramuscularly
IV Intravenously
IT Int5rathecally
SC Subcuteneously
Inh via inhalation
Neb via nebulisation
Routes of Administration:
Sublingual Under the tongue Nitroglycerin
Oral The drug is swallowed and absorbed through the stomach and intestinal tract Oral Glucose Aspirin
Inhalation a gas or aerosol inhaled by the patient
Oxygen by mask , Albuterol by hand-held metered- dose inhaler or by small volume nebulizer
Injection : The drug is injected into a muscle mass
Epinephrine by auto-injector
Tablets compressed powder shaped into a disk Aspirin Nitroglycerin
Liquid for Injections liquid with no particulate matter Epinephrine
Medication Forms
Gel : viscous substance that the patient swallows
Suspension : drug particles mixed in a solute
Fine powder for Inhalation : a crystalline solid mixed with liquid to form a suspension e. g. Albuterol by hand-held metered-dose inhaler
Gas : Oxygen by mask
Spray Nitroglycerin sub-lingual spray
Liquid/vaporized Albuterol by small-volume nebulizer
Steps to Administering Medication
Obtain an Order ,Confirm Order Select Proper Medication ,Avoid contamination ,Check Expiration Date ,Check For Signs of Contamination
Discoloration Cloudiness Particulate Matter
Verify Form & Route
Inform Patient of Order
Inquire about allergies
Recheck Medication Expiration date,Contamination
At least two more times after initial check.
Steps to Administering Medication:Assess Patient prior to administration of the drug.Administer the correct dose by the correct route.Dispose of Contaminated Equipment. Reassess After Administration
Risk versus benefit:Negligible risk, Acceptable risk ,Unacceptable risk
How should you choose a drug?We choose according to Safety & tolerability , Efficacy ,Cost-effectiveness.
Why take a drug history? Drugs:( Adverse effects ,Allergy , Abused Addiction ) can cause disease (early or late)can conceal disease,can give diagnostic clues , can interfere with diagnostic tests ,history can assist treatment choice
The prescription – pitfalls (unsuspected danger or difficulty )
Doses &Route:Choose an appropriate route e.g. is the patient vomiting?
Care with doses with different routes e.g. Penicillin 1.2g iv versus 1.2mg intrathecal.Do not use the im route if patient is anticoagulated
Vancomycin example Cl difficile 125mg qds PO Staph aureus 1g bd IV
Dose reduction: In Elderly, renal failure, hepatic failure
Children :Dose often calculated by weight & Paediatric pharmacopoeia available.
Rate includes :Bolus vs Infusion e.g. Vancomycin “red man syndrome”
Frusemide and ototoxicity
Minutes or hours , ml or mg e. g.
GTN 50mg in 50ml (5% dextrose) at 1 to 10 ml per hour
Cost of Cl Difficile& in PU treatment course: Metronidazole 3000- 50000 ID Vancomycin 150 000ID Rabeprazol Sodium 36000ID
How can we contain cost? By Appropriate prescribing ,Generic prescribing , Therapeutic substitution , Timely discontinuation
However, many patients do not receive treatment from which they would clearly benefit (e.g. in hyperlipidaemia and heart failure)
Compliance Also: adherence / concordance / co-operation
25-50% of patients take < 90% of prescribed dose
May be due to poor understanding, so cannot comply
Can occur in the face of good understanding
Main reasons for poor compliance:
1 . Poor doctor-patient relationship
2 . Lack of motivation
3 . Forgetfulness
4 . Deliberate intention
5 . Lack of information
6 . Frequency & complexity of drug regimen (and total number of drugs)
How can we improve compliance?Form a ‘partnership’ with the patient
Provide oral and written information ,Rationalise drug therapy
Plan treatment around the patient’s life ,Use ‘patient-friendly’ packaging
Use combined fixed-dose & SR formulations,See the patient regularly
Use dosette box if appropriate
In Summary
Prescribing is an important responsibility . Potential to do harm as well as good
Good prescribing is fundamental to being a good doctor
William Withering
In 1789 said : “Poisons in small doses are the best medicines; and useful medicines in too large doses are poisonous”
Questions you should ask before you prescribe any drug
Is it really necessary … could it replace a drug already being taken?Avoid polypharmacy wherever possible, especially in the elderly
Is the dose correct and the route/formulation appropriate? Check with the BNF in all cases during your prescription
Will concurrent medications interact? Check it out
Should it continue indefinitely?
[What is the evidence for its efficacy?] Efficacy does not necessarily mean it will improve clinical outcome RCTs (based on clinical outcome) are the gold standard
Therapeutics Dr Monem Alshok 12\4\2011
Lectures in Therapeutics :
Overview ,Prescription
Adverse Reaction ,Drugs Interaction
Prescription in special situations : Pregnancy , Breast Feeding , Elderly , Renal & Hepatic diseases.
Corticosteroids & Diuretics
Clinical Trials
Introduction to clinical Therapeutics: Prescription :
The administration of medicines is an event that requires professional judgement. Administration should be undertaken and recorded in a manner, which is clearly understood by the prescriber, nurse, pharmacist and other health care individuals involved in the patients care. Medicines should be prescribed only when they are necessary, and in all cases the benefit of administering the medicine should be considered in relation to the risk involved. This is particularly important during pregnancy when the risk to both mother and fetus must be considered . It is important to discuss treatment options carefully with the patient to ensure that the patient is content to take the medicine as prescribed . In particular, the patient should be helped to distinguish the side-effects of prescribed drugs from the effects of the medical disorder. When the beneficial effects of the medicine are likely to be delayed, the patient should be advised of this.
Goals in Clinical Therapeutics :
The goal is for you to acquire a general understanding about how drugs exert their therapeutic effect, and as importantly learn how to prescribe them safely and appropriately.The diseases and conditions to be treated .The evidence that a particular drug or therapy is effective. Whether benefits are on quality or quantity of life number needed to treat / risk reduction .The context in which drugs should be used (i.e. other effective drugs . The mechanism(s) of action precautions in use ,important contra-indications . Important adverse reactions likely benefits versus cost of treatment
Potential developments within the next 2-3 years
Good prescribing practice:
To be a good doctor, it is essential to understand and apply the principles of prescribing medicines. Therapeutics lies at the heart of medicine and is what doctors do on a daily basis. Therefore having a grasp of the concepts underlying good prescribing is mandatory in order to deliver the best possible care for patients. Conversely, bad prescribing and medication errors affect up to 17% of patients in the UK (some still prove fatal the cost is around £400 million annually) more importantly the associated harm to patients, is avoidable if medicines are prescribed appropriately.
Remember the “Golden Rule” of prescribing
if in doubt, check it out
Drug Indications: details of uses and licensed indications, Indication is the reasons for administering a medication or performing a treatment.
Cautions: details of precautions required (with cross reference to any appendices) and also any monitoring required.
COUNSELLING: verbal explanation to the patient of specific details of the drug treatment (e.g. posture when taking a medicine)
Contra-indications: details of any contra-indications to use of drug. A factor that prevents the use of a medication or treatment (eg. Allergies )
Side-effects: details of common and more serious side effects
Dose: dose and frequency of administration (max.dose); CHILD specific age group
By alternative route, dose and frequency
Pharmaceutical form, colour, coating, active ingredient and amount in dosage form, net price, pack size and ELDERLY details of dose for specific age
Points to remember when you write a prescription:
ALWAYS write legibly in ink or other indelible.
ALWAYS sign & date the prescription (it is a legal document!)
NEVER abbreviate drug names ,NEVER use proprietary names ,ALWAYS use generic names* PREFERABLY use plain English for dosing direction
Dose :The amount of a drug to be administered at one time
Mechanism of Action :How a drug works.
When you write the INDIVIDUAL DOSE:
for STRENGTHS >1g use grams e.g. 100 g
for STRENGTHS <1g use milligrams e.g. 100 mg
for STRENGTHS <1mg use micrograms e.g. 100 microgram (NEVER use µg )
AVOID unnecessary decimal points e.g. use 300 mg NOT 0.3 g
Effects: The desired result of administration of a medication
Side Effects: Effects that are not desired and that occur in addition to the desired therapeutic effects
Drug Names:
Broadly speaking, drugs have three different names.
1. The approved (non-proprietary) or generic name is what ought to be used if possible, unless a specific preparation of the drug is required ( diltiazem ).
2. The chemical name is seldom used in clinical practice 3.whereas the proprietary or brand name should be avoided as this can vary greatly, depending on where you are in the world. For example, acetylsalicylic acid (chemical name) is widely known as aspirin (approved name); in the UK, it is available as numerous branded formulations (eg. “Disprin” or “Anadin” etc), which may not be available or indeed recognized in other countries.
Prescribing abbreviations
Although directions for use should preferably be in English without abbreviation, it is recognized that some Latin abbreviations are used when prescribing drug timings:
ante cibum (before food) a.c.
bis die (twice daily) b.d.
omni die (once daily) o.d.
o.m. - omni mane (every morning)
o.n. - omni nocte (every night) p.c. - post cibum (after food)
p.r.n. - pro re nata (when required) nebulisation
q.d.s. - quater die sumendus (four times daily)
q.q.h. - quarta quaque hora(every four hours)
stat - immediately (NB. only by specialist) t.i.d. - ter in die (three times daily)
Prescribing Abbreviation Routes
N.G. via naso-gastric
IM intramuscularly
IV Intravenously
IT Int5rathecally
SC Subcuteneously
Inh via inhalation
Neb via nebulisation
Routes of Administration:
Sublingual Under the tongue Nitroglycerin
Oral The drug is swallowed and absorbed through the stomach and intestinal tract Oral Glucose Aspirin
Inhalation a gas or aerosol inhaled by the patient
Oxygen by mask , Albuterol by hand-held metered- dose inhaler or by small volume nebulizer
Injection : The drug is injected into a muscle mass
Epinephrine by auto-injector
Tablets compressed powder shaped into a disk Aspirin Nitroglycerin
Liquid for Injections liquid with no particulate matter Epinephrine
Medication Forms
Gel : viscous substance that the patient swallows
Suspension : drug particles mixed in a solute
Fine powder for Inhalation : a crystalline solid mixed with liquid to form a suspension e. g. Albuterol by hand-held metered-dose inhaler
Gas : Oxygen by mask
Spray Nitroglycerin sub-lingual spray
Liquid/vaporized Albuterol by small-volume nebulizer
Steps to Administering Medication
Obtain an Order ,Confirm Order Select Proper Medication ,Avoid contamination ,Check Expiration Date ,Check For Signs of Contamination
Discoloration Cloudiness Particulate Matter
Verify Form & Route
Inform Patient of Order
Inquire about allergies
Recheck Medication Expiration date,Contamination
At least two more times after initial check.
Steps to Administering Medication:Assess Patient prior to administration of the drug.Administer the correct dose by the correct route.Dispose of Contaminated Equipment. Reassess After Administration
Risk versus benefit:Negligible risk, Acceptable risk ,Unacceptable risk
How should you choose a drug?We choose according to Safety & tolerability , Efficacy ,Cost-effectiveness.
Why take a drug history? Drugs:( Adverse effects ,Allergy , Abused Addiction ) can cause disease (early or late)can conceal disease,can give diagnostic clues , can interfere with diagnostic tests ,history can assist treatment choice
The prescription – pitfalls (unsuspected danger or difficulty )
Doses &Route:Choose an appropriate route e.g. is the patient vomiting?
Care with doses with different routes e.g. Penicillin 1.2g iv versus 1.2mg intrathecal.Do not use the im route if patient is anticoagulated
Vancomycin example Cl difficile 125mg qds PO Staph aureus 1g bd IV
Dose reduction: In Elderly, renal failure, hepatic failure
Children :Dose often calculated by weight & Paediatric pharmacopoeia available.
Rate includes :Bolus vs Infusion e.g. Vancomycin “red man syndrome”
Frusemide and ototoxicity
Minutes or hours , ml or mg e. g.
GTN 50mg in 50ml (5% dextrose) at 1 to 10 ml per hour
Cost of Cl Difficile& in PU treatment course: Metronidazole 3000- 50000 ID Vancomycin 150 000ID Rabeprazol Sodium 36000ID
How can we contain cost? By Appropriate prescribing ,Generic prescribing , Therapeutic substitution , Timely discontinuation
However, many patients do not receive treatment from which they would clearly benefit (e.g. in hyperlipidaemia and heart failure)
Compliance Also: adherence / concordance / co-operation
25-50% of patients take < 90% of prescribed dose
May be due to poor understanding, so cannot comply
Can occur in the face of good understanding
Main reasons for poor compliance:
1 . Poor doctor-patient relationship
2 . Lack of motivation
3 . Forgetfulness
4 . Deliberate intention
5 . Lack of information
6 . Frequency & complexity of drug regimen (and total number of drugs)
How can we improve compliance?Form a ‘partnership’ with the patient
Provide oral and written information ,Rationalise drug therapy
Plan treatment around the patient’s life ,Use ‘patient-friendly’ packaging
Use combined fixed-dose & SR formulations,See the patient regularly
Use dosette box if appropriate
In Summary
Prescribing is an important responsibility . Potential to do harm as well as good
Good prescribing is fundamental to being a good doctor
William Withering
In 1789 said : “Poisons in small doses are the best medicines; and useful medicines in too large doses are poisonous”
Questions you should ask before you prescribe any drug
Is it really necessary … could it replace a drug already being taken?Avoid polypharmacy wherever possible, especially in the elderly
Is the dose correct and the route/formulation appropriate? Check with the BNF in all cases during your prescription
Will concurrent medications interact? Check it out
Should it continue indefinitely?
[What is the evidence for its efficacy?] Efficacy does not necessarily mean it will improve clinical outcome RCTs (based on clinical outcome) are the gold standard
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .