Download Lithium Toxicity - Medical Place Pharmacy Chatham

Lithium Toxicity
Robert Nashat, Pharm.D, CDE
Medical Place Pharmacy
20 Emma St, Chatham, On
Roadmap
• Lithium Background
• Pharmokinetics of
Lithium
– Lithium Toxicity
• Lithium Side-effects
– Acute and Long Term
• Lithium Toxicity
– Factors leading to Toxicity
– Drug Interactions
• Treating Lithium Toxicity
• Case
• Conclusion
Background on Lithium
• Has been used since the 1870s.
– Initially used to gout
• Also used in the treatment of symptoms
associated with depression independent of
gout.
• Fell out of favor because of side effects.
• Banned by FDA in 1940s because of fatalities
John Cade
Lithium
• Considered Standard of Therapy For Bipolar
Disease
Lithium Pharmokinetics
• Taken Orally ( Liquid and Capsule)
• Absorption
– Complete Absorption from the GI Tract
• 2-4 Hours Post-ingestion
– Long Half-life
• 12-27 Hours
• Elimination
– Excreted from the Kidney but undergoes a lot of reabsorption
(80%)
– Works very similar to Sodium in the body and is linked to
sodium concentrations.
• Levels between 0.6-1.2 meq/L
– Narrow Therapeutic Index
Lithium Toxicity
Severe Toxicity- Seizures, loss of consciousness,
coma, death
Mild Toxicity- Nausea, vomiting, Tremor, Slurred
Speech, Confusion
We have to be very careful of Drug Interactions and other
Influencing factors ( Salt Intake, Caffeine, Hydration Status)
Factors Predisposing To Lithium
Toxicity
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Renal failure
Volume depletion
CHF
Caffeine Intake
Decreased Na intake
Dehydration
Drug Interactions and Lithium Levels
• ACE Inhibitors/ARB
– Increase lithium levels
• Diuretics
– Especially HCTZ, triamterene, spironolactone
• Caffeine
• NSAIDs
– Advil, Aleve
– Increase lithium levels
• Serotonergic agents
Drug Interactions and Lithium Levels
• ACE Inhibitors/ARB
– Increase lithium levels
• Diuretics
– Especially HCTZ, Lasix
• Caffeine
• NSAIDs
– Advil, Aleve
– Increase lithium levels
• Serotonergic agents
Diuretics and the Kidney
Direutics
Increase
Lithium Toxicity
(chronic Ingestion)
Level
s[Li] mEq/L
Clinical
Manifestations
Treatment
Grade 1
1.5-2.5
Nausea
Hydration
Vomitting
(x 4-6h)
Tremor
Kayexalate
Hyperreflexia
Ataxia
Agitation
Muscular Weakness
Grade 2
2.5 -3.5
Stupor
Rigidity
Hypertonia
Hypotension
Hydration,
Kayexalate,
+/- dialysis
Grade 3
> 3.5
Coma
Seizures
Hemodialysis
What Else Should Be Done?
• Consult Renal Service
• Consult psychiatric Service
• Consult poison control/toxicology service
Lithium Side Effects
• Acute effects
– Nausea, Diarrhea
– Lethargy
– Impaired Cognitive
Functioning
– Hand Tremor
• Long Term Side Effects
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Hypothyroidism
Cardiac Effects
Weight Gain
Leukocytosis
Dermatological Effects
• Acne, Psoriasis
Putting It All Together- Case 1
• The Patient Mr. X 53 years old Presented to the
ER with
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Loose Stools from the last 2 days
Nausea
Loss of Energy
Fatigue
Known Patient of Bipolar Disorder and under treatment
by Psychiatry Care. Patient is on Lithium Carbonate
Examination
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Pulse: 108
Bp 100/70
Dehydrated
CNS: Irritable, Confused, Mild Tremor, Ataxia
CVS: Tachycardia
• Lithium Levels: 3.17 mmol/L
( Ref:0.50-1.2 mmol/L)
Diagnosis
Management
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Admit in ward
I/V Fluids
Stop the Lithium
Supportive Care
Lithium repeated after 4 days is 0.68 mmol/L
Discharged via psychiatry after one week.
Conclusion
• Important to be educated about the side
effects of Lithium.
– Mortality rate
• Approximately 25 percent with an acute overdose
• 9 percent in patients intoxicated during maintenance
therapy.
• Presentation is available on our website
• www.medicalplacepharmacy.com
• Online Medication Reconciliation Program Available
Questions?