Pharm for final

Question 1

Dexmedetomidine - indications

Answer 1

• Licensed for sedation of critical care patients
• Also used in anaesthetic practice…
• Opioid sparing e.g. in bariatric
• Awake craniotomy
• Awake fibreoptic intubation

Question 2

Dexmedetomidine - dose

Answer 2

Loading dose of 1mcg/kg
Infusion of 0.2-0.7mcg/kg/hr

Question 3

Pre-medication drugs/doses. MIDAZOLAM

Answer 3

Used in kids. Up to 20mg dose usually.

Oral/buccal 0.5mg/kg (nb unpleasant taste)
Intranasal 0.2mg/kg (nb stings)

Quick onset 10-20mins

Question 4

Pre-medication drugs/doses. TEMAZEPAM

Answer 4

Oral 10-30mg tablets

Onset 45-60mins

Question 5

Pre-medication drugs/doses. KETAMINE

Answer 5

Oral 5-10mg/kg. Onset 10-20mins
Intranasal 3-5mg/kg
Intramuscular 5mg/kg, onset 3-5mins

Question 6

Pre-medication drugs/doses. CLONIDINE

Answer 6

Oral 4mcg/kg, 45-60mins to take effect, last 6hrs

Question 7

How might you set up a TIVA pump in obese patient?

Answer 7

Servin formula. INPUT the following mass

IBW + 0.4 x (ABW-IBW)

Question 8

How does heparin work?

Answer 8

Has no DIRECT anticoagulant effect
Potentiates activity of antithrombin III
Protease inhibitor that irreversibly binds thrombin and factor Xa

Question 9

Causes of heparin resistance?

Answer 9

1. Due to AT III deficiency
2. Increased heparin clearance
3. High factor VIII levels
4. Elevated heparin-binding proteins

Causes of antithrombin III deficiency?
Congenital - autosomal dominant antithrombin III deficiency
Acquired
- Reduced ATIII synthesis: liver failure, warfarin therapy
- Renal loss: nephrotic syndrome, renal f.
- DIC

Question 10

How to treat ATIII deficiency?

Answer 10

Recombinant ATIII
FFP

Question 11

Esmolol dose?

Answer 11

0.25-0.5mg/kg bolus, follow up with metoprolol

Question 12

Dose ranges for following agents used in pre-eclampsia

Labetalol

Methyldopa

Nifedipine

Answer 12

Labetalol
- Oral 200-1600mg in divided doses
- IV 50mg bolus followed by infusion

Combined a1 and nonspecific B adrenoceptor agonism
CI in asthma, cardiac disease

Methyldopa
- Oral 250mg to 3g/day in divided doses
- False neurotransmitter to norepinephrenine

Nifedipine
- 20-90mg od
- Ca channel antagonist, blocks L-type channels

Hydralazine
- IV 5mg slow bolus, 5mg/hr

Question 13

Prilocaine 2% dose for saddle block

Answer 13

10-20mg (0.5ml-1ml)

Question 14

Prilocaine 2% dose for block >T10 e.g epigastric hernia

Answer 14

60mg (3ml)

Question 15

Prilocaine 2% dose for block >40 mins

Answer 15

40-60mg (2-3ml)
see table

Question 16

What is baclofen

Answer 16

Anti-spasticity agent

GABA-B receptor agonist
Inhibits release of excitatory neurotransmitters aspartate and glutamate in dorsal horn spinal cord

Routes
- Oral –> may cause weakness, resp depression, incontinence

• Intrathecal T12/L1 subarach catheter, implanted pump

Question 17

Obesity pharmacokinetics
ABSORPTION

Answer 17

Increased absorption of oral medications (increased gastric emptying)

Difficult IV access in the obese

Decreased SC absorption due to poor subcutaneous blood supply

IM administration may fail if needles are too short

Question 18

Obesity pharmacokinetics
DISTRIBUTION

Answer 18

markedly affected by ratio of adipose tissue to lean body mass if lipid soluble

increased Vd of lipid soluble drugs
-> dose lipid soluble drugs on actual body weight
(remifentanil is an exception, although lipophilic Vd does not change – use IBW or LBW)

no change in Vd of H2O soluble drugs (but blood, ECF, body organ and connective tissue volume are also increased)
-> dose on ideal or lean body weight

accumulation of lipophilic drugs in fat stores may increase dose required to gain effect

total body water may be increased by resuscitation volume

Cmax reduced

altered protein binding

Question 19

Obesity pharmacokinetics
METABOLISM

Answer 19

variable effects

increases in cytochrome P450 2E1 activity and phase II conjugation activity

more likely to be affected by critical illness with drug interactions

reduced hepatic blood flow

Question 20

Obesity pharmacokinetics
ELIMINATION

Answer 20

T1/2 increased of lipid soluble drugs due to accumulation

obese patients with normal renal function have increased GFRs
-> increased clearance of drugs excreted by the kidneys

co-existing disease will effect this (e.g. nephropathy associated with diabetes and hypertension)

calculated and measured creatinine clearance correlate poorly in obesity and in critical illness

Question 21

Obesity drugs table

Answer 21

Question 23

Pharmacological options for severe intra op Brady

Answer 23

Atropine 500mcg to 1mg
Adrenaline 10-50mcg boluses
Isoprenaline 0.02-0.2 mcg /kg/min