Chapter 4: Nervous System Flashcards
What is dementia?
Dementia is caused when the brain is damaged by diseases such as Alzheimer’s, strokes or parkinson’s
Dementia cognitive symptoms ?
- memory loss e.g. difficulty recalling
- difficulties thinking e.g. concentration or problem solving
- language e.g. cant find the right word
- orientation e.g. losing track of the date
Dementia non-cognitive symptoms?
- psychiatric and behavioural problems e.g. delusions or aggression
- difficulties with daily activities
Management of mild-moderate alzheimers disease?
ACETYLCHOLINESTERASE INHIBITORS
- donepezil (neuroleptic malignant syndrome; risk increased with concomitant antipsychotics)
- galantamine (stop at first appearance of skin rash; serious skin reactions can occur e.g. SJS)
- rivastigmine (use in parkinsons disease. GI disturbances: withold until resolved. Transdermal patches - less GI side effects)
Management of moderate-severe alzheimer’s disease?
NMDA GLUTAMATE RECEPTOR ANTAGONIST
- memantine (anticholinesterases are c/i in moderate/severe)
Cholingeric side effects: (parasympathomimetic)
DUMB BELS Diarrhoea Urination Muscle weakness, muscle cramps, miosis Bronchospasm
Bradycardia
Emesis (vomiting)
Lacrimation (teary eyes)
Salivation/sweating
Management of non-cognitive dementia symptoms?
ANTIPSYCHOTIC DRUGS
- for severe non-cognitive symptoms causing significant distress or immediate risk of harm to self or others
MHRA ADVICE: clear increased risk of stroke and death when antipsychotics are used in elderly patients with dementia.
- carefully assess benefits and risk including any history of:
- stroke/TIA
- cerebrovascular disease risk factors: HT, diabetes, AF, smoking
Management of extreme violence, agression and extreme agitation?
- Oral benzodiazepines or antipsychotic
If IM needed for behaviour control: haloperidol, olanzapine, lorazepam
Management of dementia with lewy body (parkinsons disease)?
- acetylcholinesterase inhibitors i.e. rivastimine
What is epilepsy?
A sudden surge of electrical activity of neurons in the brain.
What are non-epileptic seizures?
Unrelated to abnormal electrical activity in the brain and are of 2 types:
- organic: e.g. hypoglycaemia, fever
- psychogenic (mental/emotional processes) e.g distressing thoughts
5 types of seizures ?
- focal (partial) seizures with/without secondary generalisation
- tonic-clonic seizures
- absence seizures
- myoclonic seizures
- atonic/tonic seizures
Treatment for focal (partial) seizures with/without secondary generalisation?
FIRST LINE = lamotrigine or carbamazepine
Alternative = levetiracetam, valproate, oxcarbazepine
Treatment of tonic-clonic seizures?
FIRST LINE = Valproate or lamotrigine alternative
Also first line option = Carbamazepine
Absence seizures treatment?
FIRST LINE = ethosuximide or valproate (high risk of generalised tonic-clonic seizure)
Alternative = lamotrigine
Myoclonic seizures treatment?
FIRST LINE = Valproate
Alternative = topiramate, levetiracetam
Atonic/tonic seizures treatment?
FIRST LINE = valproate
Antiepileptic drug brands warning?
MHRA ADVICE: antiepileptic drugs: potential harm when switching between different manufacturer products for a particular drug in the treatment of epilepsy
Which antiepileptic drugs is it advised to maintain on same brand?
CATEGORY 1: carbamazepine, phenytoin, phenobarbital, primidone. Rx should include brand name OR generic name + manufacturer
Which antiepileptic drugs brand maintaining is based on clinical judgement and patient consultation?
CATEGORY 2: valproate, lamotrigine, clonazepam, topiramate
Which antiepileptic drugs do not need to maintain on same product?
CATEGORY 3: levetiracetam, gabapentin, pregabalin, ethosuximide
- for category 2+3 also consider:
- patient perceptions of differences in supply e.g taste or confusion
- difficulties for co-morbid autism, mental health issues, or learning diability
Withdrawal of antiepileptics?
- gradually reduce the dose under specialist supervision
- avoid abrupt withdrawal; can precipitate severe rebound seizures
- withdraw one antiepileptic drug at a time if on combination therapy
Epilepsy and the DVLA?
INFORM DVLA
- can drive car, NOT large goods or passenger carrying vehicle
1 year:
- seizure free
- established seizure pattern where no influence on consciousness
- no history of unprovoked seizures
- seizure due to prescribed change or withdrawal (earlier if treatment reinstated for 6 months and no further seizures)
Sleep seizures:
- after each sleep seizure. Can drive IF:
- history of no awake seizures for 1 year from first sleep seizure
- established pattern of sleep seizures fro 3 years
When are you banned from driving with epilepsy?
- during medication changes or withdrawal
- 6 months after last dose
- 6 months for first unprovoked epileptic seizure or single isolated seizure
(5 year ban for large goods or passenger carrying)
Antiepileptics and pregnancy, which drugs increase risk of teratogenicity ?
HIGHEST RISK - valproate/valproic acid: minor and major congenital malformations & long term developmental disorders
INCREASED RISK - carbamazepine, phenytoin (antifolate), phenobarbital, primidone, lamotrigine
CLEFT PALATE: topiramate in first semester
What antiepileptic drug increases cleft palate risk in pregnancy?
Topiramate in first semester
Which antiepileptic drug reduces the efficacy of hormonal contraception?
ENZYME-INDUCING ANTI-EPILEPTICS e.g. carbamazepine
What drugs need dose adjustments based on plasma drug concentration in pregnancy?
Phenytoin, carbamazepine, lamotrigine
With which drugs do you need to monitor foetal growth in pregnancy?
Topiramate/levetiracetam
What to do when planning a pregnancy on antiepileptics?
options: withdrawal and resume after the 1st trimester OR monotherapy
What can be taken in pregnancy to reduce the risk of neural tube defect?
5mg folic acid daily, taken before conception until week 12 of the pregnancy
What minimises the risk of neonatal haemorrhage?
Vitamin K injection in newborn
Which drugs can cause withdrawal effects in newborns?
Especially benzodiazepines and phenobarbital
What needs to be monitored when breastfeeding on antiepileptics?
- drowsiness
- weight gain
- feeding difficulty
- adverse effect
- developmental milestones
Which antiepileptic drugs are present in high amounts in breast milk?
- zonisamide
- ethosuximide
- lamotrigine
- primidone
(ZELP)
Which antiepileptic drugs accumulate due to slower metabolism in infant?
- phenobarbital
- lamotrigine
Which antiepileptic drugs inhibit infant’s sucking reflex in breastfeeding?
- phenobarbital and primidone (largely converted to phenobarbital)
Which antiepileptic drugs have an established risk of drowsiness in babies breastfeeding?
- benzodiazepines
- phenobarbital
- primidone
Which antiepileptic drugs should you avoid abrupt withdrawal of breastfeeding ?
Risk of withdrawal symptoms especially with phenobarbital/primidone
Antiepileptic drugs side effects?
- anti-epileptic hypersensitivity syndrome
- risk of suicidal behaviour and thoughts (can occur within 1 week report any mood changes/distressing thoughts)
- skin rashes
- blood dyscrasias
- eye problems
- encephalopathic symptoms
What is anti-epileptic hypersensitivity syndrome and what drugs are associated with it?
- Rash, fever, lymphadenopathy and systemic involvement in first 1-8 weeks of starting; discontinue immediately.
- Associated with certain antiepileptics drugs e.g. carbamazepine, phenytoin, phenobarbital, primidone and lamotrigine (CP3L)
- Risk of cross-sensitivity between antiepileptic drugs: e.g. carbamazepine and phenytoin
Which antiepileptic drugs are associated with skin rash side effects?
- lamotrigine; steven-johnson syndrome, toxic epidermal necrolysis
- higher risk: high initial dose, rapid dose increase, with valproate
Which antiepileptic drugs are associated with blood dyscasias side effect?
- carbamazepine, valproate, ethosuximide, topiramate, phenytoin, lamotrigine, zonisamide: C Vet Plz
- counselling: report signs of infection, bruising or bleeding
Which antiepileptic drugs are associated with eye problems ?
- vigabatrin: visual field defects
- counselling: report new visual symptoms
- topiramate: acute myopia with secondary angle-closure glaucoma. Also choroidal effusions and anterior displacement of lens and iris.
- counselling: report signs of raised intra-ocular pressure
Which antiepileptic drugs are associated with encephalopathic symptoms ?
- vigabatrin; marked sedation, stupor and confusion with non-specific slow wave EEG. withdraw or reduce dose
MHRA/CHM advice for gabapentin and resp depression?
gabapentin is associated with rare risk of severe respiratory depression even without concomitant opioid medications.
Patients at higher risk:
- compromised resp function
- respiratory disease or neurological disease
- elderly
- renal impairment (gabapentin is renally cleared)
- concomitant use of CNS depressants e.g. benzodiazepines, opioids, hypnotics, barbiturates, antipsychotics, lithium, antidepressants, alcohol, antiepileptics
What antiepileptic drug is an enzyme inhibitor which leads to increased plasma concentrations?
Sodium valproate
Which antiepileptic drugs are enzyme inducers and result in decreased plasma concentrations?
- carbamazepine
- phenytoin
- phenobarbital
Interacts with oral contraceptives and warfarin
Phenytoin MOA?
Binds to neuronal sodium channels in their inactive state; prolongs inactivity
HIGH RISK DRUG (NARROW THERAPEUTIC INDEX)
Phenytoin use (indication)?
Focal seizures and generalised tonic-clonic seizures. Exacerbates absence and myoclonic seizures - AVOID
What is the therapeutic range for phenytoin?
10-20mg/L or 40-80micromol/L
What is the relationship between phenytoin dose and plasma concentration?
Non-linear
- small changes in dose/missed doses/change in drug absorption = large changes in plasma concentration
Is phenytoin protein bound or not?
- Highly protien-bound
When protein-binding is reduced, monitor the plasma free-drug concentration: pregnancy, children (neonates < 3 months), elderly and liver failure. These pt groups can show early signs of toxicity.
Neonates <3 month have therapeutic range: 6-15mg/L or 25-60micromol/L
Signs and symptoms of phenytoin toxicity?(SNAtCHeD)
Slurred speech
Nystagmus (uncontrolled repetitive eye movements e.g eye rolling)
Ataxia (lack of voluntary co-ordination of muscle movement
Confusion
Hyperglycaemia
Diplopia (double vision), Blurred vision
Do you have to maintain on the same brand of phenytoin?
Yes - phenytoin is a risk category 1 antiepileptic drug, different oral formulations vary in bioavailability: phenytoin sodium is NOT bioaequivalent to phenytoin base
What is the dose conversion for phenytoin sodium to phenytoin base?
100mg phenytoin sodium = 92mg phenytoin base
Phenytoin side effects?
- change in appearance: acne, hirsutism, gingival hypertrophy (maintain good oral hygeine)
- blood dyscasias (phenytoin is also an antifolate): report signs of infection e.g. fever, sore throat, mouth ulcers, or unexplained bruising or bleeding. monitor FBC
- hypersensitivity reaction: antiepileptic hypersensitivity syndrome. report fever, rash, swollen lymph nodes
- rashes (skin disorders): report rashes, discontinue. If mild reintroduce cautiously but discontinue if recurrence
- low vitamin D = ostomalacia and rickets (phenytoin induces vitamin D metabolism.
- hepatotoxicity: discontinue stat and do not re-administer
- suicidal ideation
Pre treatment screening for phenytoin: what patients have an increased risk of Steven-Johnson syndrome?
Han chinese and thai patients with HLA-B*1502 allele
Signs of liver toxicity?
Dark urine, nausea and vomiting, abdominal pain, itching, jaundice
Side effects of IV phenytoin?
- bradycardia, hypotension
- other common side effects: arrhythmias, cardiovascular collapse. respiratory arrest. If too rapid = CVS/CNS depression (monitoring ECG/BP) If bradycardia or hypotension occurs reduce administration rate
Side effects of IV infusion of fosphenytoin?
Severe cardiovascular reactions
- asystole, ventricular fibrillation, cardiac arrest, heart block, hypotension and bradycardia (monitoring: heart rate, BP, resp function during infusion and observe patient for 30 mins after infusion)
If hypotension occurs reduce infusion rate or discontinue
Fosphenytoin 1.5mg = phenytoin sodium 1mg
Fosphenytoin (prodrug of phenytoin) given IV and IM only, has less injection site reactions and can be given more rapidly with IV
Which drugs interact with phenytoin to increase phenytoin concentration (toxicity)?
- amiodarone
- cimetidine
- miconazole
- fluconazole
- chloramphenicol
- metronidazole
- clarithromycin
- fluoxetine
- sertaline
- diltiazem
- valproate (enzyme inhibitors)
- trimethoprim (also increased antifolate effect)
Which drugs interact with phenytoin to reduce phenytoin conc (therapeutic failure)?
- St johns wort
- rifampicin (enzyme inducers)
Which drugs interact with phenytoin to antagonise anticonvulsant effects?
- quinolones
- tramadol
- mefloquine
- SSRIs
- antipsychotics
- TCA and related antidepressants (lowers seizure threshold)
What drugs interact with phenytoin to increase antifolate effect = increased risk of blood dyscasias ?
- methotrexate
- trimethoprim
Phenytoin is an enzyme inducer, which drugs does it reduce the drug concentrations of ?
- hormonal contraceptive/HRT (reduced efficacy)
- warfarin (reduces anticoagulant effect)
- corticosteroids
- levothyroxine, liothyronine (increased risk of hypothyroidism)
Carbamazepine MOA?
- inhibits neuronal sodium channels, stabilises membrane potential and reduces neuronal excitability
HIGH RISK NARROW THERAPEUTIC INDEX
Carbamazepine use (indication)?
- First line in focal seizures, generalised tonic-clonic seizures
- Exacerbates atonic, clonic and myoclonic seizures
Carbamazepine therapeutic range?
4-12mg/L or 20-50micromol/L
Plasma carbamazepine monitoring: measured after 1-2 weeks
Signs and symptoms of carbamazepine toxicity? iHANDBAG
ico-cordination
Hyponatraemia
Ataxia (lack of volutary co-ordination of muscle movement)
Nystagmus (uncontrolled repetitive eye movements e.g. eye rolling
Drowsiness
Blurred vision and diplopia (double vision)
Arrythmias
Gastro-intestinal disturbance (nausea, vomiting and diarrhoea)
Carbamazepine side effects?
- blood dyscrasias e.g. leucopoenia, thrombocytopenia pt counselling: report signs of infection e.g. fever etc monitor FBC
- hepatotoxicity, monitoring LFTS
- hypersensitivity reactions: antiepileptic hypersensivitiy syndrome
- rashes (avoid in HLAB*1502 as well as phenytoin)
- hyponatraemia (in rare cases can lead to water intoxication)
MR Preparations can reduce risk of side effects
What carbamazepine side efects are dose-related and dose-limiting?
- headache
- ataxia
- drowsiness
- nausea
- vomiting
- blurred vision
- unsteadiness
- allergic skin reactions
more common at the start of treatment and in elderly patients
What drugs interact with carbamazepine to increase concentration (toxicity)?
- cimetidine
- macrolides
- fluoxetine
- miconazole
(enzyme inhibitors)
Which drugs decrease carbamazepine concentration?
- st johns wort
- phenytoin
(enzyme inducers)
Which drugs antagonise anticonvulsant effect when given with carbamazepine?
- quinolones
- mefloquine
- SSRIs
- antipsychotics
- TCA and related antidepressants
(lowers seizer threshold)
Which drugs increase the risk of hyponatraemia when given with carbamazepine?
- aldosterone antagonists
- SSRIs
- TCAs
- diuretics
- NSAIDs e.g. naproxen
Which drugs increase the risk of hepatotoxicity when given with carbamazepine?
- tetracyclines
- sulfasalazine
- sodium valproate
- methotrexate
- isoniazid
- statins
- fluconazole
- alcohol
Carbamazpine is an enzyme inducer, reduces concentration of what drugs ?
- warfarin (possible reduces anticoagulant effect)
- hormonal contraceptives/HRT (reduced efficacy)
Sodium valproate MOA?
Weak inhibitor of neuronal sodium channels, stabilises resting membrane potential and reduces neuronal excitability
Sodium valproate use?
First line in all types of generalised seizures
MHRA alert for sodium valproate in women and girls?
(most teratogenic antiepileptic)
: c/i in women and girls of childbearing potential unless in pregnancy prevention programme and only if not alternatives. c/i in pregnant women for bipolar disorder and only considered in epilepsy if no other alternative
What can be done to support patients on the PPP?
- patient info card
- annual specialist review
- dispense as whole pack - warning labels and stickers
Sodium valproate side effects ?
- hepatotoxicity (potentially fatal)
- report signs of liver toxicity e.g. vomiting, abdominal pain, jaundice, malaise, drowsiness
- LFTS - discontinue if abnormally prolonged prothrombin time
- blood dyscasias e.g. leucopeonia, thrombocytopenia
- report sign of infection e.g. fever, sore throat, mouth ulcers, or bruising/bleeding
- pancreatitis
- report abdominal pain, N+V
Which drugs cause an antagonised anticonvulsant effect when given with sodium valproate?
- quinolones
- mefloquine
- SSRIs
- antipsychotics
- TCA and related antidepressants
(lowers seizure threshold)
Which drugs increase the risk of hepatotoxicity when given with sodium valproate?
- statins
- carbamazepine
- tetracyclines
- fluconazole
- isoniazid
- itraconazole
- methotrexate
- sulfasalazine
(hepatotoxic drugs)
Is valproate an enzyme inducer or inhibitor?
INHIBITOR; increases drug concentration
- e.g. of lamotrigine, phenobarbital
What is status epilepticus ?
Epileptic fits follow one after the other without regaining consciousness
What treatment is given for convulsive status epilepticus?
IV lorazepam
Avoid IV diazepam; causes thrombophlebitis
What treatment is given for non-convulsive status epilepticus?
If incomplete loss of awareness:
- continue or restart usual oral antiepileptic drug
If complete loss of awareness or failure to respond to oral antiepileptic drug:
- treat same as convulsive
What are febrile convulsions and what is used to treat?
Seizures that occur when a child has a high fever
- paracetamol (antipyretic) if >5 mins treat the same as status epilepticus
What is done if convulsive seizures or febrile seizures have been going on for longer than 5 mins?
- diazepam rectal solution OR
- midazolam oromucosal solution
repeated once after 10-15 mins if necessary
Anxiety psycohological symptoms?
- restlessness
- worry
- fear
- difficulty concentrating
- irratbility
Anxiety physical symptoms?
- palpitations
- muscles aches and tension
- trembling or shaking
- excessive sweating
- SOB
- insomnia
Drugs used to treat anxiety ?
BENZODIAZEPINES (CD 4 part 1)
- alprazolam (LA)
- clobazam (LA, also adjunct in epilepsy)
- chlordiazepoxide (LA, also adjunct in acute alcohol withdrawal)
- diazepam (LA)
- lorazepam (SA)
- oxazepam (SA)
- use SA in elderly, liver impairment but carries greater risk withdrawal symptoms
BETA-BLOCKERS
BUSPIRONE (5HT1a agonist)
low potential for abuse and dependence, takes 2 weeks to work
ANTIDEPRESSANTS
ANTIPSYCHOTICS
Benzodiazepines MOA?
Facilitates and enhances the binding of GABA to the GABAa receptor to cause widespread depressant effect on synaptic neurortransmission
- clinical manifestations include anxiolysis, sedation, muscle relaxation and anticonvulsant effects
Benzodiazepine use?
Short term (2-4 weeks) relief of anxiety that is severe, disabling or causing patient unacceptable distress
Long acting benzodiazepines?
- alprazolam
- clobazam
- chlordiazepoxide
- diazepam
Short acting benzodiazepines?
- lorazepam
- oxazepam
Benzodiazepine side effects?
- paradoxical increase in hostility aggression: range from talkativeness and excitement to aggression and antisocial acts, increased anxiety and perceptual disorders also occur
- sedation: careful driving/operating machinery, avoid alcohol
- dependence: avoid long term use and avoid abrupt withdrawal
- overdose: ataxia, drowsiness, dysarthria, nystagmus, resp depp/coma
What is benzodiazepine withdrawal syndrome?
Increased anxiety, insomnia, weight loss, tremors, sweating, loss of appetite, perceptual disorders, tinnitus
Occurs within a day of stopping a short acting benzo
Occurs within 3 weeks of stopping a long acting benzo
Steps for benzodiazepine withdrawal?
- gradually convert (over 1 week) to equivalent diazepam done ON
- reduce diazepam dose by 1-2mg increments every 2-4 weeks (up to 1/10th every 1-2 weeks for high doses)
- reduce diazepam dose further, can reduce in smaller steps of 500mcg towards the end
Which drugs cause increased sedation and CNS depressant effects when given with benzodiazepines?
- alcohol
- opioids
- antihistamins
- antidepressants
- barbiturates
- antipsychotics
-z-drugs
(sedating drugs)
Which drugs increase plasma concentrations of benzodiazepines?
- amiodarone
- diltiazem
- macrolides
- fluconazole
(enzyme inhibitors)
ADHD symptoms?
- hyperactivity
- impulsivity
- inattention
ADHD treatment in chidren 5+?
FIRST LINE: methylphenidate (concerta, medikinet, equasym)
SECOND LINE: Lisdexamfetamine (elvanse)
Alternative: atomoxetine guanfacine
ADHD adult treatment ?
FIRST LINE: Methylphenidate/lisdexamfetamine
Alternative: atomoxetine
Methylphenidate MOA?
Potent CNS stimulant; increases dopamine and noradrenaline levels in the brain
Methylphenidate side effects?
- appetite loss, insomnia, weight loss
- increased heart rate and BP
- tics and tourettes
- growth restriction in children (monitor height and weight)
Methylphenidate monitoring?
- pulse, BP, appetite, weight and height on starting, dose change and every 6 months
- psychiatric symptoms: e.g depression, psychosis and suicidal ideation
Methylphenidate contraindications?
- CVD, hyperthyroidism, severe hypertension, uncontrolled bipolar disorder, severe depression
- prescribe by brand for MR preparations
Dexamfetamine and lisdexamfetamine MOA?
Potent CNS stimulant; increases dopamine and noradrenaline levels in brain
Lisdexamfetamine side effects?
- appetite loss, anorexia
- increased heart rate and blood pressure
- tics and tourettes
- growth restriction in children
Signs of lisdexamfetamine overdose?
- wakefulness
-hyperactivity - paranoia
- hallucinations
- hypertension
followed by - exhaustion
- convulsions
- hyperthermia and coma
Lisdexamfetamine monitoring?
- pulse, BP, appetite, weight and height on starting, after dose change and every 6 months
- psychiatric symptoms
Lisdexamfetamine c/is?
- CVD, hyperthyroidism, moderate/severe hypertension, agitated states
Atomoxetine MOA?
Noradrenaline reuptake inhibitor causes increased levels of noradrenaline at synaptic cleft
Atomoxetine side effects?
- suicidal ideation (report suicidal thoughts etc)
- hepatotoxicity (report signs of liver toxicity)
- QT prolongation (avoid concomitant drugs that also prolong QT interval
Atomoxetine monitoring?
- pulse, BP, psychiatric symptoms, appetite, weight and height at start/dose change/every 6 months
How is Bipolar disorder characterised?
2 types of episodes:
1. Mania - feeling very high and overactive (less severe is called hypomania)
- Depression - very low and lethargic
What is used to treat acute episodes of mania and hypomania?
- benzodiazepines - short term use (risk of dependence)
- antipsychotics = Quetiapine, Olanzapine or Risperidone
- lithium or valproic acid is added to antipsychotic if inadequate response.
- asenapine (2nd gen) in moderate/severe manic episodes
What is used for the prophylaxis of bipolar disorder - 2 years?
- lithium salts
- valproate (valproic acid or sodium valproate)
- olanzapine (if response in manic episode)
- carbamazepine (rapid-cycling bipolar disorder unresponsive to other drugs
Contraindications in bipolar disorder?
Do not give antidepressants:
- rapid-cycling bipolar disorder, recent history of hypomania, manic episode, rapid mood fluctuations
Lithium salts MOA?
(high risk, narrow therapeutic window)
- MOA not fully understood
Lithium use?
Prophylaxis and treatment of mania, hypomania, and depression in bipolar disorder, resistant depression and aggressive or self-harming behaviour
Lithium therapeutic range ?
- 0.4mmol/L to 1mmol/L (lower end of prophylactic treatment/elderly)
- 0.8mmol/L to 1mmol/L for acute manic episodes, patients who have previously relapsed or have subsyndromal symptoms
Plasma lithium monitoring?
- blood sampes taken 12 hours post dose
- monitored every 3 months
- additional monitoring if significant intercurrent illness or significant changes to diet or water intake
Avoid abrupt withdrawal
Signs and symptoms of lithium toxicity? (REVeNGe)
- Renal disturbances: polyuria, hypernatraemia
- Extrapyramidal symptoms: fine tremor increasing to coarse tremor, ataxia, dysarthria, myoclonus, nystagmus and muscle weakness
- Visual disturbances e.g. blurred vision
- Nervous system disturbances: confusion, drowsiness increasing to incoordination, restlessness and stupor
- GI effects e.g. diarrhoea and vomiting
> 2mmol/L = renal failure, arrythmias, seizures, blood pressure changes, circulatory failure, coma and sudden death
Lithium side effects?
Mild cognitive/memory impairment, thyroid disorders with long term use
- thyroid disorders (TFTs) hyper or hypo
- renal impairment (monitor renal function) report polyuria/polydipsia
- benign intracranial hypertension (report persistent headaches, visual disturbance)
- QT prolongation (monitor cardiac function)
- lowers seizure threshold
- hyponatraemia predisposes to lithium toxicity
- prescribe by brand
Lithium counselling points ?
- report signs and symptoms of lithium toxicity
- maintant constant adequate salt and water intake especially in intercurrent infection, diarrhoea or vomiting = dehydration
- lithium treatment pack: alert card
- driving and skilled tasks: lithium can cause drowsiness, avoid alcohol
- OTC interactions e.g. ibuprofen, soluble analgesics, antacids
- teratogenic: effective contraception - toxicity can occur in breastfeeding
Which drugs can cause an increased risk of seizures when given with lithium>?
- ciprofloxacin (quinolones)
- SSRIs
- epilepsy
(lowers seizure threshold)
Which drugs can cause QT prolongation (increased risk of arrhythmias) when given with lithium?
(drugs that prolong QT interval) - quinolones - citalopram (SSRI) - clarithromycin (macrolides) - amiodarone - antipsychotics - imipramine (TCAs) (drugs that cause hypokalaemia) - theophylline - corticosteroids - B2 agonists - loop/thiazide
Which drugs cause hyponatraemia (which predisposes to lithium toxicity)?
- diuretics (loop thiazides, K+ sparing, aldosterone antagonists)
- antidepressants (SSRI, TCAs)
Which drugs increase the risk of extrapyramidal symptoms when given with lithium?
- haloperidol
- clozapine
- phenothiazines
(antipsychotic drugs) - parkinsons
- metoclopramide
Which drugs affect salt balance when given concomittantly with lithium?
OTC interactions: soluble/effervescent analgesics (high salt), sodium containing antacids
Which drugs increase the risk of neurotoxicity when given with lithium?
- phenytoin
- carbamazepine (antiepileptics)
- antipsychotics
- amitriptyline
Which drugs increase the risk of serotonin syndrome when given with lithium?
- sumatriptan (5HT1a agonists)
- citalopram (SSRIs)
- granisetron
- MAOIs
- amfetamines
- st johns wort
- tramadol
Depression psychological/physical symptoms ?
PSYCHOLOGICAL
- low self esteem
- worry and anxiety
- suicidal thoughts
PHYSICAL SYMPTOMS
- lack of energy
- changes in weight/appetite
- insomnia: early morning wakeness
Antideppressant general MOA?
Depression is said to be caused by the underactivity of monoamine neurotransmitters. Antidepressants increase monoamine levels at synapse
Tricyclic antidepressants ?
(Raises 5-HT, NA)
- amitriptylline (also used in neuropathic pain)
- clomipramine
- doselupin (dangerous in overdose - specialist use)
- doxepin
- imipramine (most antimuscarinic TCA)
- lofepramine (hepatotoxicity)
- nortriptylline (also used in neuropathic pain)
- trimipramine
TCA related
- mianserin
- trazodone
SSRIs? (selective serotonin reuptake inhibitors)
(raises 5-HT)
- citalopram (QT prolongation)
- escitalopram (QT prolongation)
- fluoxetine (only antidepressant given in children)
- fluvoxamine
- paroxetine (greater risk of withdrawal reactions)
- sertraline (safe to use after MI/unstable angina)
Irreversible monoamine oxidase inhibitors?
(Raises 5-HT, NA, DA)
- phenelzine (hepatotoxicity more likely)
- isocarboxazid (hepatotoxicity more likely)
- tranylcypromine (hypertensive crises more likely)
Reversible monoamine oxidase inhibitors ?
- moclobemide ( no washout period needed; short acting)
Other antidepressant drugs?
- agomelatine (hepatoxicity; give treatment booklet)
- duloxetine (SNRI also used in diabetic neuropathy)
- flupentixol (antipsychotic)
- mirtazepine (blood dyscrasias)
- reboxetine (NRI)
- tryptophan
- venlafaxine (SNRI; higher risk of withdrawal reaction)
- vortioxetine
First line antidepressants?
SSRIs
- better tolerated and safer in overdose than other classes
- less sedating, antimuscarinic, epileptogenic, cardiotoxic than TCAs
MAOIs are rarely used; dangerous food and drug interactions.
How long to antidepressants take to work?
MINIMUM 2 weeks
- initially feel worse; increased agitation, anxiety, and suicidal ideation
- review every 1-2 weeks at start of treatment
- wait at least 4 weeks (6 weeks in elderly) before deeming it ineffective