Cardiovascular Agents

Question 1

DIGOXIN- acute OD

Answer 1

R
- Usual

R
Potentially lethal if:
- >10mg adult
- >4mg child
- Dig level >15 nmol (12 ng)
- K >5.5 (100% mortality untreated!)
- Kids: accidental usually benign
….(Toxic is like 10x normal dose.)

S
ANTICIPATE:
- GI upset
- Then, arrhythmia, hypotension, arrest
–> automaticity and AV blocks

-SUPPORT:
- Usual
- HyperK but NOT CALCIUM (Stone Heart)
- AV block: atropine (pacing futile)
- Ventric arrhythmia: Lignocaine (defib futile)

I
- 12-lead, BGL, parac (delib)
- Dig level at 4 hours, then Q2H (stop checking after fab- inacc)

D
- AC: yes

E
- No

A
- DIGOXIN IMMUNE FAB
EMPIRICAL:
5 amps if stable
10 amps if unstable –> Then 5 amps, 30-minutely
20 amps if arrested x1
KNOWN DOSE:
(amps = ingested dose mg x 0.8 x 2)

D
OBSERVE
–> 6 hours

Question 2

Non-digoxin sources of digitalis:

Answer 2

Oleander
Foxglove
Rhododendron
Lily of the Valley
Toad

Question 3

DIGOXIN- Chronic poisoning

Answer 3

Consider in anyone on dig with CNS/ CVS/ GI symptoms

DIAGNOSIS:
- Steady state (6 hours post dose)
- Tx range: 0.5 - 1 ng (0.6 - 1.3 nmol)
—> Wildly high = prob toxic
—> A bit high…. consider along with symptoms.

ADDIT SX:
–> Yellowed vision/ haloes (xanthopsia)
–> Disturbance of colour

DIGOXIN IMMUNE FAB:
- 2 amps. Can repeat x1.
or
- amps = (serum level (ng) x kg)/ 100

Question 4

ECG in DIGOXIN TOXICITY:

Answer 4

Digoxin ‘effect’:
- ‘Reverse tick’
–> Downsloping, saggy ST depression with TWI
- Short QT

Digoxin toxicity
Manifestations of
1- Increased automaticity
2- Decreased AV conduction
3- HyperK +-
- PVCs
- Sinus brady
- AV blocks
- Slow (or regularised) AF
- VT

Question 5

CLONIDINE OD

Answer 5

>20 microg/kg potentially significant
2 tablets can kill in child

Triad:
- Sedation
- Miosis
- Bradycardia
…. Hypotension/ shock RARE.

Supportive (incl atropine/ pressors PRN)

• NALOXONE 0.1mg IV x4
  –> Rescue/ bridge only.

Observe 6 hours

Question 6

CALCIUM CHANNEL BLOCKER OD

Answer 6

R
- Usual

R
- ALL are potentially serious
- Beware: Verapamil XR and Diltiazem XR
–> Even 2x normal dose dangerous.
–> >10tabs life-threat.
- Immediate-release not usually life-threat.
- Kids: “one pill can kill (XR). 2 pills IR.”

S
ANTICIPATE:
- DELAYED ONSET (12+ hours) with XR!!

• Bradycardia
• AV block
• REFRACTORY hypoTN/shock
• Hyperglycaemia

-SUPPORT:
- For shock, try usual things:
–> Fluid
–> Vasopressors (*eg. adrenaline)
–> Pacing
….. but often ineffective.

I
- 12-lead, BGL, parac (delib)

D
- AC: Yes
–> Within 1 hour IR and 4 hours XR + ALL tubed patients.

E
- WBI: Consider within 4 hours, in ASx patients who have taken life-threat OD.

A
- Euglycaemic HIGH DOSE INSULIN
–> Start at 1st sign of toxicity
–> Titrate gluc to euglyc/ insulin to HD improvement
–> 10-minutely BSL
–> Hourly K
- CALCIUM GLUCONATE
–> 6g IV over 10mins. +/ Repeat 20min x3.

D
–> VA ECMO, IABP reasonable if failing.

OBSERVE 4 hours IR/ 16 hours XR with 4-hourly ECG

Question 7

BETA BLOCKER OD

Answer 7

R
- Usual

R
- Most BB OD benign, even in children
- Risk is:
–> Propanolol >1g
–> Sotalol
- Higher risk if: old, heart/lung disease/ already on

S
ANTICIPATE:
- Bradycardia and hypoTN
- AV block and bradyarrythmia
- PROPANOLOL = Na channel blockade + coma/seizure
- SOTALOL = Long QT/ Torsades (K+ blockade)

-SUPPORT:
- Usual
- Treat wide QRS (propanolol) as per TCA:
–> Sodi bic 8.4% 1mmol/kg
- Treat QT prolong/ Torsades (sotalol) as per Torsades:
–> MgSO4 2g, isopren/pace

I
- 12-lead, BGL, parac (delib)

D
- AC: yes (2 hours). Caution in propan: coma/seizure

E
- No

A
- Euglycaemic HIGH DOSE INSULIN if refractory
- Lipid emulsion (intralipid) if refractory propanolol

D
OBSERVE 6 hours

Question 8

ACE INHIBITOR OD

Answer 8

• Benign (irrespective of dose)
• Kids: up to 2x adult daily dose don’t need to come to hospital
• Fine for cubicle with normal obs
• Only really mild hypotension
• Supportive- may need fluid bolus
• Observe 4 hours