CH ppt Flashcards
1
Q
A
2
Q
What is altered physiology in children related to drug metabolism?
A
Low production of gastric acid and erratic gastric emptying in the first year of life
Altered physiology also includes smaller ratio of gut surface area to body mass and greater gut permeability to larger molecules.
3
Q
How does the body fat composition in children affect drug distribution?
A
Greater proportion of body fat and larger extracellular volume may alter the volumes of distribution of some drugs.
4
Q
What is the significance of drug-metabolizing enzyme maturation in children?
A
Maturation of drug-metabolizing enzyme pathways in the liver occurs at different rates over the first year.
5
Q
Describe the absorption characteristics in neonates.
A
Slower rates of gastric emptying and intestinal transit; gastric pH is neutral, reducing absorption of weak acids but increasing absorption of weak bases.
6
Q
What is a key difference in distribution of drugs in neonates compared to adults?
A
Neonates have a lower body fat content and higher total body water, impacting distribution of water and lipid soluble drugs.
7
Q
What effect does lower plasma albumin concentration in neonates have on drug binding?
A
Lower plasma albumin concentration and higher free fatty acid concentration may increase the proportion of drug able to cross the blood–brain barrier.
8
Q
Why should drugs strongly bound to albumin be avoided during neonatal jaundice?
A
They may displace bilirubin from protein-binding sites, increasing the risk of kernicterus.
9
Q
What is the relationship between liver mass and drug clearance in young children?
A
Drug clearance is often higher in young children than in adults, due to their higher relative liver mass and greater hepatic blood flow per kilogram of body weight.
10
Q
How does renal elimination of drugs change in children by the age of 6–8 months?
A
Elimination of drugs like digoxin, gentamicin, and penicillin will be slower until about 6–8 months of age.
11
Q
What is the formula for calculating drug dose for a child?
A
Drug dose for a child = adult dose x SA of child (in m2). / 1.8
12
Q
What are the pharmacokinetic considerations for paracetamol in infants?
A
- Infants have immature liver enzyme systems affecting metabolism:
- Less NAPQI produced in overdose -> more resistant to overdose of paracetamol than adults
13
Q
Why do aminoglycosides require careful dosing in neonates and infants?
A
Kidney function is not fully developed, leading to prolonged clearance of drugs like gentamicin.
14
Q
What is a potential risk for children who are ultra-rapid metabolizers of opioids?
A
Increased risk of opioid toxicity.
15
Q
What are paradoxical reactions associated with first-generation antihistamines in children?
A
Some children may experience paradoxical excitation rather than sedation.
16
Q
oral solution vs suspension
A
- Oral solution: particles dissolved in the liquid are much smaller
- Oral suspension: particles larger so precipitate to bottom when its left, need to shake a suspension first before using
17
Q
converting units
A
18
Q
How does long-term use of corticosteroids affect children?
A
It can affect growth and development more significantly than in adults.
19
Q
What are the common references for choosing and adjusting drug dosage in children?
A
BNF-C, NICE guidelines, medicines for children, EPS.
20
Q
preterm vs neonate vs infant.
A
Preterm: born before 37 weeks gestation
Neonate: birth to 27 days
Infant/ toddler : 28 days to 2 yrs
Child: 2 -12 yrs
Adolescent: 12 to 16/18 days
21
Q
What is the primary use of paracetamol in children?
A
Usually preferred for mild to moderate pain +/- fever.
22
Q
What should be avoided in children under 16, except in specific conditions?
A
Aspirin. Only used for kawasaki and rheumatic fever
23
Q
What is Reye’s syndrome?
A
- Usually between 5 -14 yrs
- Acute encephalopathy and fatty degeneration of the liver
- Usually occurs during recovery of viral illness, with rapid deterioration
- Associated with aspirin use
24
Q
What is the role of NSAIDs like ibuprofen in pediatric care?
A
Useful for disease with pain and inflammation +/- fever.
25
choice of analgesia in kids
1) Paracetamol
2) Add NSAID
3) P + NSAID + Opiod
26
What is the significance of rectal drug administration in children?
Bypasses first-pass metabolism and is useful in cases of vomiting.
27
What does the term 'liberation' refer to in pharmacology?
Release of drug from its administered form.
28
How does the metabolism of paracetamol differ in children compared to adults?
Children produce less NAPQI in overdose, making them more resistant to paracetamol overdose.
29
codeine considerations
* CYP2D6 variants
* Codeine ultra rapid metabolisers
* ONLY USED IN ABOVE 12S
* Cant be used in breast feeding mothers -> pass to baby through milk
29
tablet calculations
Number of tablets required = what u want/ what you’ve got
30
What are the side effects of first-generation antihistamines?
Drowsiness, dry mouth, blurred vision, nausea.
31
what is CI in CP
Ibuprofen and NSAID -> nec fascitis
32
What is the mechanism of action of antihistamines?
Act as antagonists at the H-1 receptors, blocking the effects of histamine.
33
What are the indications for using nasal corticosteroids?
Hay fever, sinusitis, non-allergic rhinitis, nasal polyps.
34
What should be avoided when using nasal corticosteroids?
Untreated nasal infections and after nasal surgery.
35
What is the mechanism of action of nasal cromoglicate?
Inhibits degranulation of mast cells, preventing the release of histamine.
36
What is the management for acute attacks of Meniere's disease?
Buccal or intramuscular prochlorperazine; admission may be required.
37
What are common symptoms requiring urgent brain imaging in vertigo?
Isolated, persistent vertigo of hyperacute onset, new onset headache, unilateral deafness.
38
What are the routes of administration for prochlorperazine during an acute attack?
Buccal or intramuscular injection
## Footnote
Admission may be required for severe cases
39
What medications may be used for the prevention of vestibular disorders?
Betahistine and vestibular rehabilitation exercises
## Footnote
These may help reduce symptoms in patients with recurrent attacks
40
What is the purpose of a short course of prochlorperazine or an antihistamine during an acute attack?
Relief of nausea and vomiting
## Footnote
Antihistamines may include cinnarizine, cyclizine, or promethazine teoclate
41
What are the indications for using antihistamines?
Vertigo and Ménière disease
42
What is the mechanism of action of prochlorperazine?
Central and peripheral dopaminergic blockade
43
List some contraindications for using prochlorperazine.
* CNS depression
* Comatose states
* Phaeochromocytoma
44
What is betahistine dihydrochloride an analogue of?
Histamine
45
What is the action of thiazide diuretics in the context of Ménière disease?
Reduce the volume of the endolymph
46
What are the first-line treatments for allergic rhinitis?
Nasal antihistamine
47
What should be prescribed for sneezing in allergic rhinitis?
An oral antihistamine
48
What should be prescribed for nasal blockage in allergic rhinitis?
An intranasal corticosteroid
49
What is the class of prochlorperazine?
Dopamine receptor antagonist
50
What are some side effects of prochlorperazine?
* Parkinsonian symptoms
* Akathisia
* Tardive dyskinesia
* Dystonia
51
What are the common side effects of cinnarizine?
* Drowsiness
* Hypotension
52
What is the urgent treatment for acute closed angle glaucoma?
Emergency medical treatment to lower intraocular pressure (IOP)
53
What is the definitive treatment for acute closed angle glaucoma?
Laser peripheral iridotomy (LPI)
54
What combination of eye drops might be used in glaucoma management?
* Direct parasympathomimetic (e.g. pilocarpine)
* Beta-blocker (e.g. timolol)
* Alpha-2 agonist (e.g. apraclonidine)
* Intravenous acetazolamide
55
What is the mechanism of action of topical beta-blockers in glaucoma treatment?
Reduces aqueous humor production
56
What are the contraindications for using topical beta-blockers?
* Asthma
* Heart block
57
What are the side effects of brimonidine?
* Dry mouth
* Upper respiratory symptoms
* Allergic conjunctivitis
58
What is the mechanism of action of carbonic anhydrase inhibitors?
Reduces aqueous humor production
59
What are the side effects of prostaglandin analogues?
* Brown pigmentation of the iris
* Increased eyelash length
60
What is the mechanism of action of miotic drugs?
Acts on M3 receptor causing iris contraction and pupil constriction
61
What is the first-line treatment for anterior uveitis?
Topical corticosteroids (e.g. prednisolone)
62
What are the P-drugs for ocular anaesthesia?
* Topical ocular anaesthetics
* For tonometry or cataract surgery
63
What is the mechanism of action of sympathomimetics used for pupil dilation?
Causes dilation of the pupil
64
What are some topical antibacterial agents used for ocular infections?
* Gentamicin
* Chloramphenicol
* Ciprofloxacin
* Fusidic acid
* Neomycin
65
What are some topical antiviral agents used for ocular infections?
* Aciclovir
66
What are some examples of antibacterial agents?
* Gentamicin
* Chloramphenicol
* Ciprofloxacin
* Fusidic acid
* Neomycin
## Footnote
These agents are used to treat bacterial infections.
67
What is the primary objective for managing ocular anaesthesia?
To formulate a basic management plan and identify drugs indicated for the management of ocular anaesthesia by the topical route.
68
What are the indications for using topical ocular anaesthetics?
* Ocular anaesthesia for tonometry
* Cataract surgery
## Footnote
It is important to understand the context in which these anaesthetics are used.
69
Name three topical ocular anaesthetics.
* Oxybuprocaine
* Lidocaine
* Tetracaine
70
How do carbonic anhydrase inhibitors work?
They inactivate carbonic anhydrase and act on the proximal convoluted tubule to prevent reabsorption of bicarbonate, sodium, and chloride, reducing blood pressure.
71
What is the mechanism of action for topical corticosteroids?
They block the inflammatory cascade and inhibit phospholipase A2, preventing the release of arachidonic acid.
72
List some indications for the use of topical corticosteroids.
* Allergic eye disease
* Anterior Uveitis
* Post-operative intraocular surgery
* Keratitis
## Footnote
Different formulations (drops, creams, ointments) are used based on the condition.
73
What are important side effects of topical corticosteroids?
* Cataracts
* Glaucoma
* Central Serous Chorio-Retinopathy (CSCR)
* Systemic effects like Cushing Syndrome
## Footnote
Awareness of side effects is crucial for patient management.
74
What is the first-line management for allergic conjunctivitis?
Topical or systemic antihistamines.
75
What are common side effects of H1 antagonists?
* Drowsiness
* Dry mouth
* Nausea
* Lightheadedness
* Headaches
* Agitation
76
Fill in the blank: The first-line treatment for scleritis is _______.
oral NSAIDs.
77
What type of agents are used to relieve ciliary spasm and pain in anterior uveitis?
Cycloplegic agents.
78
What should be done immediately for chemical eye injuries?
Irrigate the eye with water or 0.9% saline until the pH returns to normal.
79
What is the first-line treatment for blepharitis?
Hot compress.
80
What is the most common cause of bacterial conjunctivitis?
* Streptococcus pneumoniae
* Staphylococcus aureus
* Haemophilus influenzae
81
What are some treatment options for keratitis?
* Topical antibiotics (typically quinolones)
* Cycloplegic for pain relief (e.g., cyclopentolate)
## Footnote
Referral to an eye specialist is essential for contact lens wearers.
82
What is the role of topical mast cell stabilizers in allergic conjunctivitis?
They prevent the release of inflammatory chemicals from mast cells.
83
What are some non-pharmacological management strategies for allergic conjunctivitis?
* Avoidance of allergens
* Cold compress
* Artificial tears/saline solution/ocular surface lubricants
84
What is the use of lidocaine gel in ocular procedures?
It provides a more consistent anaesthetic effect and is used for cataract surgery.
85
What are the indications for systemic steroids in ocular conditions?
* Temporal arteritis
* Scleritis
* Retinitis
86
What should be avoided in the management of ocular infections?
Wearing contact lenses or sharing towels.
87
liquid calculations
Volume you want = (dose u want/ dose you’ve got) x volume you’ve got
88
concentrations
Number of grams dissolved in 100ml of solution
50% = 50g in 100ml
5% = 5g in 100ml
89
ml equiv is
gram
90
ratios
91
allergic rhinitis Mx
* Allergen avoidance
* if the person has mild-to-moderate intermittent, or mild persistent symptoms:
o oral or intranasal antihistamines
92
moderate - severe allergic rhinitis mx
* if the person has moderate-to-severe persistent symptoms, or initial drug treatment is ineffective
o intranasal corticosteroids
o severe allergic rhinitis: oral steroids
o nasal ipratropium bromide can be added when watery rhinorrhoea persists despite Tx w topical nasal steroids and antihistamines
93
allergic rhinitis - cannot be used for
* Topical nasal decongestants like oxymetazoline may be used but should not be used for long periods s as increasing doses are required to achieve the same effect (tachyphylaxis) and rebound hypertrophy of the nasal mucosa (rhinitis medicamentosa) may occur upon withdrawal
94
AH MAO
* Histamine induces an increased level of vascular perm -> swelling and dilatation of vessels
* Antihistamines stop this effect by acting as antagonists at the H-1 receptors.
* Block H1 receptors, resulting in bronchodilation, vasoconstriction, and decreased vascular permeability
95
First gen AH
* First generation antihistamines easily cross the blood-brain barrier into the central nervous system and antagonize H-1 receptor -> used to treat allergic type reactions
96
Second gen AH
* Second generation antihistamines selectively bind to peripheral histamine receptors
* H2 receptor antagonists reduce stomach acid secretion as histamine causes increased acid production -> used to treat peptic ulcers and GORD
97
H1 AH
* Chlorpheniramine
* Diphenhydramine
* Promethazine
* Allergic rhinitis, urticaria, anaphylaxis, allergic conjunctivitis
98
Most sedating AH
- Promethazie more sedating than chlorphenamine
99
H2 antihistamines
* Loratadine
* Cetirizine
100
when are nasal steroids avoided
* Avoided in the presence of untreated nasal infections and after nasal surgery (unless healed) and in primary TB
101
Nasal steroids MAO
* Reduced inflammation in the nose which can help relieve symptoms such as runny/ blocked nose
* Blocks release of cytokines, histamine, reduced expression of pro-inflammatory genes and promotion of apoptosis of eosinophils
102
side effects of nasal steroids
* stinging/ burning
* throat irritation
* bad taste in mouth
* nose bleeds
* eye changes – blurred vision/ cloudy lense
* breathing problems
103
central vertigo
If a central cause of vertigo is suspected, admit the person to hospital or urgently refer to a balance specialist (such as a neurologist or audiovestibular physician,
104
RF for central vertigo requiring urgent brain imaging
o Isolated, persistent (>24 hours) vertigo of hyperacute (seconds) onset.
o Normal head impulse test.
o New onset headache.
o New onset unilateral deafness.
o Cranial nerve weakness or sensory loss, or limb weakness or sensory loss.
o Severe ataxia.
105
Rapid relief of N and V with vertigo
buccal prochlorperazine or IM prochloperazine or cyclizine
106
less severe N and V with vertigo Mx
* Epley manouvre
* teaching the patient exercises they can do themselves at home, termed vestibular rehabilitation, for example Brandt-Daroff exercises
107
MX of MN
* ENT assessment is required to confirm the diagnosis
* patients should inform the DVLA. The current advice is to cease driving until satisfactory control of symptoms is achieved
108
Prevention of MN attacks
: betahistine and vestibular rehabilitation exercises
109
Managing acute attacks of MN
prochlorperazine
110
Phenothiazines
- Prochlorperazine
- Central and peripheral dopaminergic blockade
- Used for labyrinthe disorders, N and V, acute migrane, schizophrenia, mania
111
betahistine MAO
H1 agonist - interacts with AH
112
Diuretics in MN
* Diuretics are believed to reduce the volume of the endolymph and may be offered for maintenance therapy.
* Usually thiazides
* If the patient remains symptom-free for 6 months, diuretics may be slowly tapered and re-started if required.
113
Allergic rhinitis Tx
* The basic principle is to avoid the causative allergen
* First line: Nasal antihistamine
* Further treatment depends on symptoms:
* For sneezing, prescribe an oral antihistamine
* For nasal blockage, prescribe an intranasal corticosteroid
* Sodium cromoglicate can be used as an alternative or add on treatment
114
Prochlorperazine MAO
D2 receptor antagonist
* Acts centrally on the chemoreceptor trigger zone
115
prochlorperazine SE
EPS: Parkinsonian symptoms, akathisia,
tardive dyskinesia, dystonia
116
Acute closed angle glaucoma
* Urgent referral to an opthamologist
* Emergency medical treatment is required to lower the IOP
117
Medical Mx of glaucoma
* a. Topical agents: beta-blockers, alpha agonists, and prostaglandin analogs help lower IOP by reducing aqueous humor production or increasing outflow.
* b. Carbonic anhydrase inhibitors: Both topical (e.g., dorzolamide) and oral (e.g., acetazolamide) forms can be used to decrease aqueous humour production.
* c. Systemic hyperosmotic agents: Intravenous mannitol rapidly lowers IOP by drawing fluid out of the eye.
118
definitive mx of glaucoma
laser peripheral iridotomy (LPI
119
Mx of other eye in glaucoma
a high risk of developing AACG. Prophylactic LPI is often recommended to prevent future attacks.
120
Glaucoma - LPI CI/ unsuccessful
: surgery like trabeculectomy, glaucoma drainage devices etc
121
