Antidotes

Question 1

What drug is useful in sympathomimetic OD (amphetamine, norad, adrenaline etc.)

Answer 1

PHENOLAMINE 1mg, IV, 5 minutely

Alpha blockade
Provides ‘sympathectomy*

Question 2

PROTAMINE dose for UFH reversal:

Answer 2

1mg protamine per 100units UFH received in the last 3 hours. (MAX 50mg)

For bolus heparin:
–> Dose > 30mins ago? Give HALF.
–> Dose >2 hours ago? Give QUARTER.

Question 3

PROTAMINE dose for LMWH reversal:

Answer 3

Only 60% reversal

……going to be 50mg (max dose) for almost everyone.

1mg protamine per 1mg LMWH in last 8 hours (MAX 50mg)

Question 4

PROTAMINE adverse effects:

Answer 4

Flushing, vomiting
Bradycardia, hypoTN

Question 5

HIGH DOSE INSULIN euglycaemic regimen:

Answer 5

• Glucose 50ml of 50% (25g) IV bolus
• Actrapid 1 unit/kg IV bolus

then
- Actrapid 0.5-1 units/kg/hr infusion
- Glucose 10% 100ml/hr —-> go to 50% PRN

Other:
- Titrate glucose to euglycaemia (5-10)
- Titrate insulin to HD improvement

• Monitor:
  –> BSL 10 minutely
  –> K hourly
  –> Mg/Ph intermittently

Question 6

URINARY ALKALINISATION

Answer 6

• 2mmol/kg IV SodiBic
  –> 150mmol over 4 hours

Aim urine pH 7.5 - 7.55

• 4-hourly gas
• Monitor and correct K
• Frequent dipstick

Question 7

Octreotide:

Answer 7

DOES
Powerfully suppresses endogenous insulin release

INDIC
Onset of hypo in sulphonyl OD

DOSE
50microg IV —> 25microg/hr
Paed: 1microg/kg IV —> 1 microg/kg/hr

Double rate (along with gluc bolus) if ongoing hypo despite above.

STOP
Run at least 24/24
Stop when BSL stable 12 hours post infusion off

OTHER
Can be given subcut as alternative, but slower
—> 100microg SC 6 hourly

Question 8

MECHANISMS of SODI BIC in toxicology:

Answer 8

SERUM ALK (>7.4)
- Acidosis correction
- Improve Na channel function (via Na + alk)
- Stops CNS distrubution (ionises)

URINE ALK (>7.5)
- Prevents tubular resorption (ionises)
- Increased solubility of toxin (incl myoglobin)

Question 9

Desferrioxamine:

Answer 9

DOES
Chelator. Binds free iron to form stable compound that gets excreted

INDIC
Iron OD
>60mg/kg
Level >90
Manifestations of toxicity

DOSE
15-40mg/kg/hr

Beware hypoTN

STOP
Stable
Level <60

Rose Urine

Question 10

Physostigmine:

Answer 10

DOES
Ach-esterase inhibitor (procholinergic)

FOR
Anticholinergic delirium- only treats central features, not other (eg. retention)
Pure antichol OD (eg. atropine)

DOSE
1mg IV. Repeat Q10min.
Not usually more than 4mg.
Beware AV block- check baseline ECG prior.

Question 11

Pralixodime:

Answer 11

DOES
Reactivates the inactivated AcH-esterases

FOR
Organophosphate poisoning with clinical features
Nerve agents
—> to treat the resp paralysis (nic)

DOSE
2g IV —> 500mg/he
Paed: 50mg/kg —> 20mg/kg/hr

STOP
Give for 24 hours

OTHER
Minimal side effects
Only effective early, before AcH-esterase binding is irreversible

Question 12

Cyproheptidine

Answer 12

DOES
Anti-serotonergic (and antihistamine)

FOR
Mild-mod serotonin syndrome
For symptom relief, not curative. These patients do well anyway.
No role in severe.

DOSE
4 (child) - 8 mg PO Q8H
Usually relief a couple hours after 1st dose

STOP
After 24/24

OTHER
No adverse