lithium Flashcards
contraindications
Addison’s disease
Cardiac disease associated with rhythm disorder
Cardiac insufficiency
Dehydration
FHx/ personal Hx Brugada syndrome
Untreated hypothyroidism
Low sodium diet
does lithium affect pt with epilepsy
yes can lower seizure threshold
Long term use of lithium is associated with …
Thyroid disorders and mild cognitive and memory impairment
Only undertake long term use with careful assessment of risk and benefit, and with monitoring of thyroid function every six months or more often if evidence of deterioration
How often to measure thyroid function
6 monthly
more often if evidence of deterioration
The need for continued therapy should be assessed regularly and patients should be maintained on lithium after …. many years only if benefit persists
3-5 yrs
How many hours after first dose should you take samples to achieve serum lithium concentration of 0.4-1mmol/L
12 hours
What is the target serum lithium concentration (+ for maintenance + elderly)
0.4-1mmol/L
Lower end of range for maintenance therapy and elderly
What is the target serum lithium conc for acute episodes of mania, pt previously relapsed or subsyndromal symptoms
0.8-1mmol/L
How often to do serum lithium monitoring
weekly after initiation and after each dose change until concentration stable
Then every three months for the first year
Then every six months thereafter
interactions (nephrotoxic drugs)
Diuretics: increase conc of lithium, avoid or adjuse dose and monitor concentration
NSAIDs: increase conc of lithiym, monitor and adjust dose
ACEI/ARBs: increase conc lithium, momitor and adjust dose
NSAIDs also can increase risk nephrotoxicty
Tetraycclines predicted to increase risk lithium toxicity, avoid or asjust dose
Signs of overdose - what to do
Signs of intoxication require withdrawal of treatment
Signs: increasing GI disturbances such as vomiting and diarrhoea, visual disturbances, polyuria, muscle weakness, fine tremor increasing to coarse trauma, CNS disturbances (like confusion and drowsiness increasing to lack of coordination, restlessness, stupor), abnormal reflexes, myoclonus, incontinence, HYPERnatraemia
In severe overdosage seizures, cardiac arrhythmias (including SA block, bradycardia and 1st degree heart block), BP changes, circulatory failure, renal failure, coma, sudden death
Use in pregnancy and BF
Effective contraception during treatment for women of childbearing potential
Avoid in pregnancy if possible especially first trimester due to risk of teratogenicit including cardiac abnormalities
Dose requirements are increased during second and third trimesters but on delivery return abruptly to normal dose
Closely monitored several lithium concentration in pregnancy due to risk of toxicity in neonate
Avoid in breastfeeding due to risk of toxicity in infant
Dose requirements of lithium are increased in which trimesters
2 and 3
on delivery return abruptly to normal dose
monitor the following patients every 3 months (instead of every 6 months after being on It for a year)
65 and older
Taking drugs that interact with lithium
At risk of impaired renal or thyroid function
Raise calcium levels or other complications
Poor symptom control or poor adherence
Last serum lithium concentration was 0.8mmol/L or higher
Additional serum lithium measurements should be made if a patient develops ……. or if there is significant change in ……
significant intercurrent disease or if there is significant change in a patient sodium or fluid intake
monitoring pt parameters
Before: Assess renal, cardiac, thyroid function, BW/BMI, electrolytes, FBC
ECG recommended in patients with CVD or risk factors for it
6 monthly: BW/BMI, electrolytes, EGFR, thyroid function; more often if evidence of impaired renal or thyroid function, or raise calcium levels
Also monitor cardiac function regularly
T or F - abrupt discontinuation increases risk of relapse
true
T of F - stopping lithium causes withdrawal or rebound psychosis
no clear evidence
If lithium is to be discontinued, dose should be gradually reduced over period of
at least four weeks, preferably over a period of up to three months
If lithium is stopped or is to be discontinued abruptly, consider changing therapy to
atypical antipsychotic or valproate
Patient and carer advice
Report signs and symptoms of lithium toxicity, hypothyroidism, renal dysfunction including polyurea and polydipsia, benign intracranial hypertension such as persistent headache and visual disturbance
Maintain adequate fluid intake and avoid dietary changes would to reduce or increase sodium intake
Give lithium treatment pack to patients on initiation of treatment
what are the most common interactions with lithium (8)
Diuretics increase serum lithium levels by reducing clearance
NSAIDs may increase serum lithium levels
SSRIs, TCAs, SNRIs increased risk of CNS toxicity (serotonin syndrome)
ACEi decrease excretion of lithium and can precipitate renal failure
Serotonin syndrome
Dapagliflozin can decrease serum lithium levels
Haloperidol - neurotoxicity
Carbamazepine - neurotoxicity
Tetracyclines - toxicity
what is the interaction between lithium and amitriptyline, clomipramine etc
neurotoxicity
caution
also serotonin syndrome
what is the interaction between lithium and ARBS (-sartan)
they can increase conc of lihtium
monitor conc and adjust dose
what is the interaction with lithium and diuretics
increase the conc of lithium
avoid or adjust dose and monitor conc
what is the interaction with lithium and NSAIDs
increase conc of lithium
monitor and adjust dose
what is the interaction with bupropion and lithium
serotonin syndrome
monitor
what is the interaction with lithium and ACEi (2)
they can increase ltihium conc
monitor and adjust dose
also nephrotoxicity
interaction with carbamazepeine
increased risk neurotoxicity
lithium is a ,…. toxic drug
nephro
lithium is a nephrotoxic drug. these abx are also nephrotoxic, increasing the risk (4)
cephalosporins
gentamicin
trimethoprim
vancomycin
interaction with lithium and chlorpromazine, levomepromazine
neurotoxicity
discontinue if neurotoxicity develops
avoid this class of abx with lithium - why
tetracyclines
they increase risk of lithium toxicity
avoid or adjust dose
interaction with diltiazem, verapamil
neurotoxicity
caution
interaction with MAOIs
serotonin syndrome
interaction with linezolid
serotonin syndrome
interaction with dexamfemaine, lisdexamfetamine
serotonin syndrome
Rx comes in for a pt who regularly takes priadel for prophylaxis of bipolar disorder. She is suffering from acne and has been prescribed lymecycline 408mg OD. what do you do
Contact the doctor because tetraycclines increase risk of lithium toxicity, avoid or adjust dose.
interaction with methyldopa
neurotoxicity
interaction with metronidazole
increases conc of lithium
avoid or adjust dose
patient comes in with dental script for metronidazole 400mg TDS for 7 days. the other meds she takes includes priadel. What do you do
Call up dentist and ask them for alternative as metrodniazole increases conc of lithium, avoid or adjust dose
is lithium a serotinergic drug
yes so will interact with others e.g. ADs, triptans, 5ht3 antagonists, methadone, tramadaol, pethidine, tapentadol etc
interaction with quetiapine
neurotoxicity
discontinue if it develops
interaction with risperidone, sulpiride
neurotoxicity
discontinue if it develops
interaction with amino, theophylline
decrease conc of lithium
monitor and adjust dose
Role of sodium in lithium
Hyponatremia predisposes to lithium toxicity because low sodium levels cause the kidneys to retain lithium.
Hypernatremia is seen as a symptom in severe lithium toxicity due to dehydration from vomiting, diarrhea, or lithium-induced nephrogenic diabetes insipidus.
dose in elderly
will require reduced dose
what to do about dose in infection, vomtiting, diarrhoea
review dose as necessary in diarrhoea; review dose as necessary in intercurrent infection (especially if sweating profusely); review dose as necessary in vomiting;
Excessive sweating, fever, vomiting, or diarrhea can lead to dehydration and sodium loss. Often need to reduce dose to avoid dehydration-related toxicity. Monitoring hydration, symptoms, and lithium levels closely will guide safe management in these situations.
can NMS happen
yes rarely discontinue
how to manage poisoning
Levels above 2 mmol/L typically indicate serious toxicity and may require haemodialysis if neurological symptoms or renal failure are present.
In cases of acute overdose, much higher lithium levels can occur without toxicity symptoms; in such cases, increasing urine output by hydrating (without diuretics) is usually sufficient.
Treatment is generally supportive, focusing on electrolyte balance, renal function, and seizure control.
Gastric lavage may be useful if performed within 1 hour of significant ingestion, and whole-bowel irrigation may be considered with advice from the National Poisons Information Service.
What electrolyte imbalance can it cause
hypercalcaemia
(hypoNa in some cases but less often)
Pt reports headache that is very frequent and visual problems. This is their medication list. What could it be
- Atorvastatin 20mg
- aspirin 75mg
- amlodipine 10mg
- priadel 200mg
- vit B12
could be benign intracranial hypertension - see GP
