paediatrics Flashcards
1
Q
What are the main factors that affect drug absorption?
A
pH-dependent passive diffusion
Gastric emptying
2
Q
What is the main reason for the neutral gastric pH at birth?
A
Presence of amniotic fluid in the stomach
3
Q
What factor allows for increased drug absorption and potential toxicity in infants due to an immature blood-brain barrier?
A
Increased permeability
4
Q
In sick or injured children, dehydration can increase the risk of medication toxicity due to:
A
Increased water loss and decreased oral fluid intake
5
Q
Which group has the highest total body water content as a percentage of body weight?
A
Preterm infants
6
Q
Why do lipophilic drugs like diazepam have a smaller volume of distribution in infants?
A
Infants have lower fat stores.
7
Q
Why do premature and newborn babies have slower drug metabolism?
A
Because their liver enzyme systems are not fully developed and are immature at birth.
8
Q
How does drug metabolism change after the newborn period?
A
Many drugs are metabolized more quickly, which may require larger doses or more frequent dosing.
9
Q
What effect does reduced liver enzyme and plasma/tissue esterase activity have in neonates?
A
It slows drug metabolism and clearance, extending the effects of some medications
10
Q
How do drug-metabolizing enzyme systems change after birth?
A
Most systems are present at birth but increase in activity with advancing gestational and postnatal age.
11
Q
Why is gastric pH neutral at birth?
A
Due to the presence of amniotic fluid in the stomach.
12
Q
When does gastric acid start to be produced postnatally?
A
Gastric acid is usually made 24-48 hours after birthand the acidity decreases for several weeks to months and eventually reaching adult levels by 3 mnths..
13
Q
Why do premature neonates have a higher, less acidic gastric pH apart from due to amniotic fluid?
A
Due to immature acid secretion.They also experience slower gastric emptying and reduced function of pancreatic enzymes and bile, affecting drug absorption
14
Q
How does gastrointestinal (GIT) immaturity affect drug absorption in infants?
A
Infants have shorter transit times, which can reduce the absorption of medications.
15
Q
What risk is associated with the increased permeability of the blood-brain barrier (BBB) in children?
A
immature BBB in children allows for increased permeability whichcan result in potential systemic toxicity.
16
Q
At what age does the central nervous system (CNS) fully mature?
A
Around 8 months old.
17
Q
How can fluid loss in sick children affect drug toxicity?
A
Dehydration from increased water loss can raise the risk of medication toxicity.
18
Q
How does the proportion of body fat and water change with age, and how does it affect drug distribution in children?
A
Fat increases with age, altering the distribution of fat-soluble drugs, while infants have more total body water, affecting water-soluble drug distribution (water-soluble have a higher volume of distribution).
19
Q
What is the total body water percentage in adults, infants, and preterm infants?
A
Adults: 55%, Infants: 70-75%, Preterm infants: 85%.
20
Q
Why do drugs that bind to proteins have a greater effect in children and how does diminished protein binding affect a drug?
A
Because protein binding is less in children, leaving more of the drug ‘free’ and active, potentially increasing drug effects. Diminished protein binding can cause a portion of a drug to remain in an active, unbound state.
21
Q
At what age does protein binding in newborns reach adult levels?
A
Around 1 year old.
22
Q
What are hepatic phase 1 reactions, and when do they reach adult levels?
A
Phase 1 reactions (oxidation, reduction, hydroxylation) are responsible for breaking down drugs and reach adult levels by 6 months of age
23
Q
Which drugs are affected by hepatic phase 1 reactions developing quickly after birth?
A
Drugs like phenobarbital, phenytoin, and diazepam.
24
Q
What are hepatic phase 2 reactions, and how are they affected at birth?
A
Phase 2 reactions (conjugation), which help the body eliminate drugs, are reduced at birth and take several months to fully develop.
25
What is the state of enzyme systems responsible for oxidation and methylation in premature neonates?
These systems are active in premature neonates, but enzymes for oxidative demethylation develop several months later.
26
What adjustments may need to be made when administering drugs that undergo hepatic metabolism in infants?
You may need to increase the dosage or reduce the dosing interval to account for faster or slower metabolism
27
Why do neonates have lower kidney function and reduced drug clearance?
Due to underdeveloped glomeruli, short loop of Henle, and immature renal tubules until 6 months
28
What factors contribute to altered drug clearance in neonates?
Decreased glomerular filtration rates, immature liver function, deficiency in pancreatic enzymes, decreased plasma protein and albumin levels, increased total body water, and decreased gastrointestinal transit times.
29
What is the glomerular filtration rate (GFR) at birth, and when does it reach adult levels?
GFR is very low at birth (2-4 ml/min) but increases dramatically in the first 72 hours, reaching adult levels by 5 months
30
When does tubular secretion mature in children?
Tubular secretion matures by about 1 year of age.
31
How does renal drug elimination depend on kidney maturation in children?
Renal drug elimination improves as the kidneys mature, which affects how quickly drugs are cleared
32
Why are infants particularly sensitive to drugs that affect the CNS?
Because the BBB is not fully developed at birth, allowing easier access for drugs to the CNS
33
How can an underdeveloped BBB be advantageous in cases of meningitis?
Drugs can more easily access the CNS, which may aid in treating CNS infections like meningitis.
34
What is a potential consequence of neonates having more body fat than preterm infants?
Drugs may have a prolonged effect due to storage in body fat
35
What are some unique ADRs in children related to organ immaturity?
Growth suppression (from glucocorticoids), tooth discoloration (from tetracyclines), and kernicterus (from sulfonamides)
36
What is kernicterus, and which drug class is associated with this condition in neonates?
Kernicterus is a severe neurodevelopmental condition associated with hyperbilirubinemia, and it is linked to sulfonamides.
37
How do plasma concentrations from intranasal medications compare to other routes?
Nasal mucosa produces plasma concentrations similar to IV administration for some drugs.
38
Which medications can be administered via the intranasal route?
Medications like Midazolam, Fentanyl, and Morphine can be given intranasally.
39
How should a child be positioned when receiving nasal drops to avoid discomfort?
The child's head should be extended over a pillow or the edge of the bed to prevent medication from trickling down the throat.
40
Why can Otic medications cause discomfort for children even though the procedure is not painful?
Otic medications are often stored in the fridge, and the cold liquid in the ear can create an unpleasant sensation.
41
What is a common issue when administering Ophthalmic medications to children?
Gaining the child's cooperation can be difficult, and the drops can cause an unpleasant sensation.
42
How should Ophthalmic drops be administered to a child?
Place one drop in the inner corner of the eye and press lightly on the nasolacrimal duct for 10-15 seconds to improve absorption and prevent the medication from entering the nasal cavity.
43
What explanation should be provided to a child before giving nasal drops?
The explanation should be age-appropriate, explaining what will happen and why, to ensure cooperation
44
Why do children absorb topical medications more rapidly than adults?
Children have a greater total body surface area to weight ratio, which promotes greater absorption.
45
Why should topically applied medication be used sparingly in infants?
Infants absorb topical medications more rapidly and completely, which increases the risk of systemic effects.
46
What is a potential side effect of using potent steroids in children via topical application?
Hypothalamic-pituitary-adrenal (HPA) axis suppression.
47
How does percutaneous absorption differ in neonates compared to older children or adults?
Neonates have increased percutaneous absorption due to an immature epidermis and increased skin hydration
48
Why might drug absorption from an intramuscular (IM) site be unpredictable in neonates?
Insufficient blood flow, poor muscle tone, and compromised muscle oxygenation make absorption less reliable.
49
Which medications have shown variable intramuscular absorption in neonates?
Digoxin, gentamicin, phenobarbital, and diazepam.
50
Why is intramuscular administration not recommended as a long-term solution for neonates?
Neonates have limited muscle mass, making IM injections harder and absorption less predictable
51
When should rectal medication administration be considered for children?
When the oral route is difficult or contraindicated.
52
What precautions should be taken when administering rectal medications to children?
Ensure privacy, provide appropriate explanation to the child and parent, have at least 2 people present, and use a water-soluble lubricant for insertion.
53
Why is it not recommended to cut suppositories if the prescribed dose isn't available?
There is no guarantee that the drug is evenly distributed throughout the suppository.
54
What are potential side effects of administering steroids via nebulisation or inhalation in children?
Oral thrush, contact dermatitis, and cataracts.
55
What device should be used to administer inhaled bronchodilators to children with mild to moderate asthma?
MDI and spacer
56
Why is it important for parents and caregivers to be well-educated in the use of MDIs for children?
To ensure accurate medication administration and avoid errors.
57
Why should parenteral medication, such as injections, be avoided in children if another suitable route is available?
Giving injections to children is an unpleasant procedure for both the child and caregiver.
58
How should IV antibiotics be administered to paediatric patients?
In smaller volumes via burettes, according to paediatric pharmacopoeia guidelines.
59
What is the normal sodium intake for children, including dietary sodium?
3-5 mmol/kg/day.
60
What are the three types of medications that can be given to paediatric patients?
Licensed medications, licensed medications used outside of the product licence, and unlicensed medications.
61
Why are many medications not licensed for use in children?
Due to a lack of clinical trials, complications, and ethical difficulties in conducting paediatric studies.
62
What does EU legislation require regarding paediatric medication trials?
Pharmaceutical companies must conduct paediatric trials before applying for marketing authorisation.
63
Why is aspirin unlicensed for the management of fever in children?
It can cause Reye’s syndrome, a serious condition leading to neurological impairment or death.
64
Are safety, efficacy, and quality standards guaranteed for unlicensed or off-label products?
No, but unlicensed and off-label prescribing can still be appropriate when supported by significant evidence
65
What are the legal responsibilities when prescribing unlicensed or off-label medications?
The prescriber takes responsibility for their use, and the pharmacist is responsible for ensuring the quality and obtaining certificates of conformity or analysis for unlicensed medications.
66
What is considered malpractice or negligence in relation to unlicensed medication use?
Denying a patient treatment because the drug or its use is unlicensed.
67
Who is liable for harm caused by a defect in a licensed medication used within the product licence?
The pharmaceutical company is vicariously liable.
68
What are "specials" in the context of unlicensed medications?
Specials are unlicensed products purchased from manufacturers that make them under controlled conditions with quality assurance.
69
What is the advantage of using specials over extemporaneous dispensing?
Specials have a lower risk than extemporaneous dispensing due to controlled manufacturing and available certificates of analysis or conformity.
70
Why might products from different specials manufacturers not be interchangeable?
Different manufacturers may use different formulations, making their products not bioequivalent or interchangeable.
71
What challenges can arise from starting unlicensed medications in secondary or tertiary care?
Poor communication from hospitals regarding drug details can lead to continuity of care issues, including unclear indications, dosing, and formulations.
72
Why are GPs often reluctant to prescribe unlicensed medications?
GPs may be hesitant due to the cost and lack of familiarity with the medications.
73
What issue do community pharmacies face regarding unlicensed medications?
Poor stock availability, as these medications are not commonly kept on shelves.
74
How can community pharmacists ensure the appropriateness of unlicensed medication prescriptions?
They need to clinically check the prescription and understand the indication and dose for the medication.
75
What is cystic fibrosis, and how does it affect drug therapy in paediatrics?
Cystic fibrosis is the most common inherited genetic disease, affecting the apparent volume of distribution and requiring higher doses of certain drugs.
76
Which drugs have a higher clearance in cystic fibrosis patients?
Drugs such as Gentamicin, Tobramycin, Amikacin, Dicloxacillin, Piperacillin, and Theophylline may have higher clearance in these patients.
77
What is the increased risk of acute lymphoblastic leukaemia recurrence in obese children older than 10 compared to lean children?
There is a 50% increased recurrence rate in obese children
78
Why might limiting the dose of medications in obese patients lead to poorer outcomes?
It can result in under-treatment and poorer clinical outcomes.
79
How does obesity affect the volume of distribution (Vd) of lipophilic and hydrophilic drugs?
Obese patients have a higher Vd for lipophilic drugs and a lower Vd for hydrophilic medications compared to normal-weight children.
80
What physiological differences in obese children affect drug pharmacokinetics?
Obese children have higher total body water, lower percent lean mass, increased organ mass, and greater cardiac output, GFR, and serum creatinine concentrations.
81
How are drug doses adjusted in obese children?
A correction factor is applied, which multiplies the actual body weight less the ideal body weight, then adds this figure to the ideal body weight.
82
What are some examples of correction factors for drug dosing in obese children?
β-lactams: 0.3Ciprofloxacin: 0.45Aminoglycosides: 0.4
83
Why is plasma drug level monitoring important in obese children?
It helps adjust dosing for optimal therapeutic outcomes.
84
Why do many antibiotics struggle to distribute adequately in obese patients?
Many antibiotics are hydrophilic and distribute primarily to extracellular water, while adipose tissue contains approximately 30% water.
85
How is vancomycin dosed in overweight and obese children?
Vancomycin is dosed using actual body weight without capping at the usual maximum adult dose, and its distribution is into total body water and other tissues.
86
What dosing frequency is typically used for vancomycin in complicated infections in obese children?
Initially every 8 hours, with possible increases to every 6 hours based on serum concentration monitoring.
87
How might gastrointestinal diseases in paediatric patients affect drug therapy?
Paediatric patients with gastrointestinal disease (e.g., celiac disease, gastroenteritis, and severe malabsorption) may require dosage adjustments.
88
What effect does hypoxemia have on drug elimination in low-birth-weight infants?
Hypoxemia has been shown to decrease the elimination of amikacin in low-birth-weight infants
89
Why might critically ill paediatric patients with severe head trauma require higher doses of phenytoin?
Critically ill paediatric patients with severe head trauma require higher than normal doses of phenytoin in part because of increased intrinsic clearance.
90
How do neonates and young infants perceive pain compared to older children or adults?
Neonates and young infants may perceive pain more intensely and be more sensitive to pain than older children or adults
91
What impact can an inadequately treated initial painful procedure have on a child?
An inadequately treated initial painful procedure may decrease the effect of adequate analgesia in subsequent procedures as a result of altered pain response patterns
92
How can children’s distractibility affect pain management?
Children are distractible, and diverting attention may help in managing pain.
93
What is the recurrence rate of acute lymphoblastic leukaemia in obese children older than 10 compared to lean children with cancer?
There is a 50% increased recurrence of acute lymphoblastic leukaemia in obese children older than 10 years of age compared with lean children with cancer.
94
What are the risks of limiting the dose in obese paediatric patients?
Limiting the dose in obese patients may lead to poorer outcomes and under-treatment.
95
How does a higher proportion of body fat in obese children affect the volume of distribution (Vd) of drugs?
Obese children have a higher Vd for lipophilic drugs and a lower Vd for hydrophilic medications compared with normal weight children.
96
What physiological differences in obese children can impact drug pharmacokinetics?
Obese children have higher total body water, lower percent lean mass, increased organ mass, greater cardiac output, GFR, and serum creatinine concentrations than normal-weight children.
97
What is the purpose of correction factors in drug dosing for obese children?
Correction factors are used to adjust drug dosing in obese children by modifying the dose based on their actual body weight and ideal body weight.
98
How is a correction factor applied in drug dosing for obese children?
A correction factor is multiplied by the actual body weight less the ideal body weight, and this figure is added to the ideal body weight. The drug dose is then determined based on this weight.
99
What correction factors are used for specific drugs in obese children?
Correction factors are 0.3 for β-lactams, 0.45 for ciprofloxacin, and 0.4 for aminoglycosides.
100
What role does plasma drug level monitoring play in dosing obese paediatric patients?
Plasma drug level monitoring should be used when possible to adjust dosing accurately in obese paediatric patients.
101
How does the water content in adipose tissue impact the distribution of antibiotics in obese children?
Adipose tissue contains approximately 30% water, meaning that many antibiotics, which are hydrophilic, may not distribute adequately in obese patients.
102
How is vancomycin dosed in overweight and obese children?
Vancomycin is empirically dosed using actual body weight in overweight and obese children, and the dose is not capped at the usual maximum adult dose.
103
What initial dosing frequency is used for vancomycin in complicated infections in obese children, and how might it change?
Initial dosing is every 8 hours, but frequency can increase to every 6 hours for complicated infections, with serum concentration monitoring used to individualize the dose.
104
Why might dosage forms of some drugs need to be altered for paediatric patients? examples
Many drugs used in paediatric patients are not available in suitable dosage forms, necessitating dilution of high concentrations intended for adults. Examples include atropine, carbamazepine, diazepam, digoxin, epinephrine, hydralazine, insulin, morphine, phenobarbital, and phenytoin. Volumes ranging from 0.01 to 0.1 mL must be measured to dispense these drugs for infants.
105
What are some challenges in administering oral drugs to paediatric patients?
Alterations, such as crushing or mixing, patient refusal, and loss of drug during administration, can affect therapy. Mixing medications in apple sauce, syrup, or other vehicles before administration is a common practice to make drugs more palatable.
106
How are antineoplastic agents dosed for paediatric patients?
Antineoplastic agents may be dosed based on body surface area (BSA), but the daily dose for paediatric patients, especially adolescents, should not exceed the maximum dose for adults.
107
Are drug interaction studies commonly performed in paediatric age groups?
Drug interaction studies are generally lacking for paediatric patients, and data are often extrapolated from adult studies. Adolescents, who may use alcohol, recreational drugs, or other medications, require special attention from healthcare providers to avoid interactions.
108
How does digoxin dosage differ between infants and adults?
Infants require a substantially higher maintenance dose of digoxin than adults due to a lower binding affinity of receptors in the myocardium for digoxin and increased digoxin-binding sites on neonatal erythrocytes.
109
Why are insulin requirements high during adolescence?
Insulin requirements are highest during adolescence due to rapid growth in individuals.
110
Why is promethazine contraindicated for children under 2 years?
Promethazine is contraindicated for children younger than 2 years because of the risk of severe respiratory depression.
111
Why does chloramphenicol pose a toxicity risk for newborns?
Chloramphenicol toxicity is increased in newborns due to immature metabolism and enhanced bioavailability.
112
What are some concerns about ethanol and sorbitol in oral drugs for paediatric patients?
Ethanol, present in some drugs like phenobarbital and ranitidinesorbitol, used in drugs such as diphenhydramine and frusemideboth may pose risks, as safe levels of these excipients for infants and children are undetermined, especially for patients on multiple medications.
113
Why are certain cough and cold remedies not recommended for young children?
Cough and cold remedies with antihistamines, decongestants, antitussives, and expectorants should not be used in children under 6 years due to unfavourable benefit-risk balance. For children 6 to 12, these remedies are available in pharmacies with advised supervision.
114
Why are tetracyclines contraindicated for specific populations, including children?
Tetracyclines are contraindicated for pregnant women, nursing mothers, and children under 8 due to risks of dental staining, enamelization defects, and decreased bone growth.
115
How does the toxicity of aminoglycosides differ between paediatric patients and adults?
Aminoglycosides appear less toxic in infants than adults. In adults, toxicity is related to peripheral compartment accumulation and individual sensitivity, while neonatal tissue compartments resemble those in adults with similar renal function, leading to a lower incidence of nephrotoxicity in infants. This suggests infants may have less tissue sensitivity to toxicity than adults.
