Restarting Medications After Overdose

Question 1

Principle 1: Do they need the medication?

Answer 1

• People are on too many medications
• You can’t overdose on something you don’t have
• The present predicts the future

Dont restart them
Move to limit med use where it’s not needed

Question 2

Principle 2: Risk vs Benefit

Answer 2

Cardiotox - esc or citalopram
- QT prolongation
- Need to check QTc

Need to show they can control bg on their own

Pt disposition
- Are they oging home?
- Staying in ICU
- Going to psych unit?
Diff levels of monitoring needed for these

Risk to nursing staff? Risk to themselves if dont restart med?

ADHD meds - cant forget about the benefits of meds it might help the person be less agitated

Question 3

Principle 3: Kinetics and Dynamics (Pharmaco,
Toxico)

Answer 3

The 5 Half Lives rule: Useful (to a point)
* From steady state:
* 97% of drug eliminated in 5 half lives
* 99.9% in 10 half lives
* Most patients recover from drug overdose in 1-4 days
* Important Considerations
* Active metabolites
* Genetic variations in CYP enzymes
* Saturation of enzymes
* Changes in physiologic milieu

How many half lives are we at
Take care of pt and ABC, the body iwll do the rest of eliminating the drugs
Usually recover 1-4 days
There are exceptions

Imipramine -
- Metabolized by 2D6
○ Poor, rapid metabolizers
- Desimipramine active metabolite
- Can saturate metabolism

Change blood or urine pH can affect drug elimination

Question 4

Most important caveat
Toxicokinetics not equal
Pharmacokinetics

Answer 4

Absopriton is diff if you take many tablets of something or 2

Slow gastric emptying, slow gut w anticholinergic fx
Extendered release pdts - dont get absorbed right away

Question 5

Clozapine elimination

Answer 5

Long elimination pattern already
80 hours in some cases
In OD even more prolonged
Can be due to antichoinergic protperties
Plateau of 25 h, drug abs is slowed down, ongoing absorption taking place
Elim process dragged out

Question 6

Principles 4: Is the patient in
withdrawal/experiencing discontinuation
syndrome?

Answer 6

• Most likely culprits:
• SSRIs
• SNRIs
• Baclofen
• Opiates
• Benzodiazepines
• Ethanol
• Beta-blockers
• Clonidine
• Is your Antidepressant Patient
  FINISHED?
  Flu like symptoms
  Insomnia
  Nausea
  Imbalance
  Sensory Disturbances
  Hyperarousal (Agitation/Anxiety)

Question 7

Baclofen withdrawal is a thing, right?

Answer 7

Yes. Yes, it is.
Onset: 24-48hours
Common Scenarios:
◦Intrathecal Pump interruption/failure
◦After overdose, failure to restart
◦Can happen with dose adjustment

Question 8

GABA-B Withdrawal looks like GABA-A
Withdrawal

Answer 8

Agitation
Confusion
Hallucinations
Autonomic volatility
Tremors

Treatment:
Restart at previous dose
(Or lower and titrate to
effect)
Benzodiazepines

Question 9

Principle 5: Is there a blood level that can be
done?

Answer 9

• Usually if a patient’s levels are in therapeutic range they can be
  restarted on their medication.
• Considerations:
• Where predictable elimination kinetics exist
• Plasma levels associated with toxicity are poorly established for most drugs
• Toxicity can occur below the therapeutic range
• Very few drugs have Therapeutic Drug Monitoring order sets
• Never order a lab just to do a test

Question 10

Principle 6: Is a drug interaction likely?

Answer 10

What have we given to the patient to treat their poisoning?
* Is this drug or poison one of the “usual suspects” for drug
interactions?
* Are we switching medication?
* Some antidepressants have washout periods that are needed

Question 11

Principle 7: Implementation and Minimizing
Risk

Answer 11

• Start low, go slow
• Restart the most clinically important drug first
• If multiple drugs are important – restart the drug with the shortest
  half life first