Chapter 4: Nervous System Flashcards
What groups of patients are short acting benzodiazepines more suitable for?
ElderlyHepatic impairment (however in acute alcoholic withdrawal a longer benzodiazepine is used)
What is a disadvantage of short acting benzodiazepines?
Carries greater risk of withdrawal symptoms
Withdrawal symptoms can occur without how much time of stopping a short acting benzodiazepine?
Within 1 day
Withdrawal symptoms can occur without how much time of stopping a long acting benzodiazepine?
Within 3 weeks
How would you reduce someone’s diazepam dose if on long term therapy to prevent withdrawal?If on high doses, how is this done?
Reduce diazepam dose, usually by 1–2 mg every 2– 4 weeksFor high doses- reduce by up to one tenth every 1-2 weeks
What schedule is methylphenidate (Concerta)?
CD2
What are the side effects of methylphenidate and dexamfetamine?
- Appetite loss, insomnia, weight loss- Increased HR and BP - Tics, Tourette’s- Growth restriction in children- monitor height and weight, allow drug free periods to grow - Psychiatric disorders. Monitor the above after a dose change and then every 6 months
What is dexamfetamine used for?
Narcolepsy Refractory ADHD
How would you treat an acute episode of mania?
Benzodiazepines. Antipsychotics- quetiapine, olanzapine, risperidone Lithium or valproic acid can be added if inadequate response
What can you use for prophylaxis of bipolar disorder?
Lithium salts Sodium valproate / valproic acid Olanzapine
What should you not give in patients with bipolar?
Antidepressants
What are the signs of lithium toxicity? (REVNG)
Renal disturbances Extrapyramidal symptoms Visual disturbances Nervous system disturbances GI side effects
If a patient has persistent headaches and on lithium, what should you do?
Refer. Lithium can cause benign intracranial hypertension
A deficiency in what electrolyte can lead to lithium toxicity?
Sodium
Can SSRIs lower seizure threshold?
Yes
What is the interaction between TCAs and antihypertensives?
Increased risk of hypotension
Is moclobemide a reversible or irreversible MAOI?
Reversible - no washout period needed as it is short acting
With what MAOIs are hepatotoxicty more likely?
Phenelzine, Isocarboxazid
What is the advice surrounding clozapine and missed doses?
2 or more doses missed, then need to re-titrate dose
Sexual dysfunction is most common with what antipsychotics?
Haloperidol and risperidone
Can antipsychotics interfere with your temperature regulation?
Yes
What are the advantages of using peripheral dopa-decarboxylase inhibitors for Parkinson’s?
Lower dose needed for therapeutic effect. Fewer side effects - nausea, vomiting, cardiovascular events
What class of drug is pramipexole?
Non ergot derived dopamine agonist
What are the side effects of ergot derived dopamine agonists?
Fibrotic reactions.
Pulmonary- look out for SOB, cough
Retroperitoneal - look out for abdominal pain and tenderness
Pericardial- look out for cardiac failure
Is COMT inhibitor monotherapy licensed in Parkinson’s?
No Used as an adjunct to levodopa
What kind of toxicity is caused by tolcapone?
Hepatotoxicty Look out for vomiting, dark urine, abdominal pain
What is the antisickness choice of drug in Parkinson’s?
Domperidone
What two electrolyte imbalances should be corrected before using 5HT3 antagonists e.g. ondansetron?
Hypokalaemia and hypomagnesaemia
True or false:Naloxone only partially reverses the effects of buprenorphine
TRUE
In what situations is it advised for patients to immediately remove a fentanyl patch?
Breathing difficultiesDrowsiness, impaired speechSigns of opioid toxicity
Can tramadol lower the seizure threshold?
Yes
True or false:You can take two doses of sumatriptan for the same attack 2 hours later?
True but symptoms must have been improved after taking the first tablet
How would you treat trigeminal neuralgia (facial pain with electric shocks in the jaw)?
Carbamazepine or phenytoin
Transient insomnia is caused by what?
Shift work
Jet lag
Is zopiclone a long or short acting hypnotic?
Short acting
For short term insomnia, hypnotics should not be used for longer than what?
3 weeks max, Ideally 1 week
Can methadone cause QT prolongation?
Yes
For short term relief of anxiety, hypnotics should not be used for longer than what?
2-4 weeks
What are the signs of benzodiazepine withdrawal?
It is characterised by insomnia, anxiety, loss of appetite and of body-weight, tremor, perspiration, tinnitus, and perceptual disturbances
During benzodiazepine withdrawal, what 3 classes of drugs should be avoided if possible (in the case of additional therapy to help with withdrawal symptoms)?
Beta blockers
Antidepressants
Antipsychotics
In terms of insomnia, in what cases are short acting hypnotics preferred?
Sleep onset insomnia
Where sedation the following day is not desirable
Elderly
Short term insomnia
In terms of insomnia, in what cases are long acting hypnotics preferred?
Poor sleep maintenance e.g. early morning awakening that causes daytime effects
If an anxiolytic effect is needed during the day Diazepam
How should transient insomnia be managed?
Usually self-limiting and short term e.g. jet lag
If a hypnotic is indicated one that is rapidly eliminated should be chosen, and only one or two doses should be given
How can chronic insomnia be managed? What are the common causes of chronic insomnia?
Rarely benefited by hypnotics and is sometimes due to mild dependence caused by injudicious prescribing of hypnotics. The underlying psychiatric complaint should be treated, adapting the drug regimen to alleviate insomnia.
Anxiety, depression, and abuse of drugs and alcohol are common causes
What is the risk of long term benziodiazepine therapy in the management of insomnia?
Can cause rebound insomnia and a withdrawal syndrome.
Is withdrawal more common with short or long acting benzodiazepines?
Short acting
Is temazepam long or short acting?
Short acting
What would be an appropriate benzodiazepine for someone suffering from insomnia with daytime anxiety?
Diazepam - long acting. Single dose at night
What role do beta blockers play in anxiety?
Can help with the autonomic physical symptoms e.g. tremor and palpitations. They do not reduce non-autonomic symptoms, such as muscle tensionThey do not help with psychological symptoms
True or false:A benzodiazepine may be used as short-term adjunctive therapy at the start of antidepressant treatment to prevent the initial worsening of symptoms.
TRUE
What is 1st line for mild depression if a patient is presenting for the first time?
Psychological therapy should be considered initially. If history of moderate or severe depression, consider antidepressant therapy
What class of drug is mirtazapine?
TETRAcycline antidepressant
Venlafaxine is generally reserved for what type of depression?
More severe
What is classed as chronic anxiety?
> 4 weeks duration
Is generalised anxiety disorder a form of acute or chronic anxiety?
Chronic
What class of drug is duloxetine?
SNRI
If changing from fluoxetine to MAOI, what is the period of time you can start this after fluoxetine has been stopped?What about starting an MAOI from other SSRIs?
At least 5 weeksWith other SSRIs, it is only 1 week
How long should a patient not drive through after an unprovoked seizure?
6 months
How long should a patient not drive through after a seizure in established epilepsy?How about if the seizure was whilst the patient was asleep?
12 months even if the patient was asleep unless:- Established pattern of only having seizures when the patient is asleep over one year- If had seizures in the past awake, need to have 3 years of only having seizures asleep
If an epileptic patient has had a seizure whilst asleep, the patient should not drive for 12 months. What are the exceptions?
UNLESS:- Established pattern of only having seizures when the patient is asleep over one year- If had seizures in the past awake, need to have 3 years of only having seizures asleep
Should an epileptic person drive during medication changes?
No
If withdrawn from an epilepsy med, how long should a patient not drive for?
6 months
What is the MHRA warning associated with the sedating antihistamine hydroxyzine?
QT prolongation
What is the therapeutic range for carbamazepine?
4-12 mg/L
Has pregabalin got an MHRA warning on the risk of severe respiratory depression?
No - Gabapentin does
What is amitriptyline used for?
Major depressive disorder- not recommended
Migraine prophylaxis
Neuropathic pain
What would be the starting dose of amitriptyline for neuropathic pain?
10-25mg ON Max of 75mg
What is pregabalin used for in terms of pain?
Peripheral AND central neuropathic pain
What is the max dose of pregabalin a day?
600mg
6
What would be the starting dose of pregabalin for neuropathic pain?
150mg daily in divided doses
What is the max dose of gabapentin a day?
3.6g
What is gabapentin used for in terms of pain?
Only peripheral neuropathic pain
Examples of antimuscarinic drugs
Atropine Scopolamine Ipratropium Tiotropium Toleterodine Solifenacin Benztropine Trihexyphenidyl
What would be the dosing regimen of gabapentin in neuropathic pain?
Day 1 - 300mg OD
Day 2 - 300mg BD
Day 3 -300mg TDS
Effects of Atropine as antimuscarinic drug
Eye - relaxation ciliary muscle = dilation of pupil, not responsive to light, can be used prior to eye surgery but due to long duration of action (lasting days) cyclopentolate or tropicamide is preferred (lasting hours)
GI - blocks M3 Rec reducing gut motility, prolonging transit time and gastric emptying
Heart - blocks M2 receptors on SA/AV => tachycardia (^30-40bpm)
Salivary/sweat/lacrimal glands = dry mouth, dry skin and ultimately increase in body temperature
3 types cholinergic antagonists
1 antimuscarinics2 Ganglionic blockers3 Neuromuscular blockers
Scopolamine
unlike atropine has greater CNS effect and longer duration of action- prevent motion sickness- post op n+vpatch formulation effect lasting up to 3 days
Ipratropium and Tiotropium
MOA
Indication
Difference?
Block muscarinic Acetylcholine receptors without specificity for subtypes M3 block results in decreased contractility of smooth muscle in lungs = bronchodilation =& reduction of mucus secretionBoth administered as inhalation treatment for maintenance bronchospasms for pt in COPDIpratropium <= nasal spray = rhinorrea = runny noseTiotropium long acting agent dosed once dailyIpratropium short acting dosed up to qdstiotropium bromide is electrically charged, not absorbed by the GI tract and does not pass the BBB
Antimuscarinics USE
Prior to eye operation = atropine
Motion sickness = scopolamine
COPD maintenance of bronchospasms = ipratropium/tiotropium
Bladder problems = Tolterodine / solifenacin/ oxybutynin/ fesoterodine
Parkinson like disorders = Benztropine / Trihexyphenidyl
Antimuscarinics for bladder conditions
Tolterodine
Solifenacin
Oxybutynin
Fesoterodine M3 receptor. overall efficacy similar.
Trihexyphenydil
Trihexyphenidyl exerts its effects by reducing the effects of the relative central cholinergic excess that occurs as a result of dopamine deficiency.
Anticholinergic adverse effects
ABCDs A - agitation B - blurred vision C - constipation/ confusion D - dry mouth S - stasis of urine and sweating
Ganglionic blockers’ main agent?
main agent is nicotine - cig smoke; stimulates and later represses autonomic ganglia. Cholinergic agonist but also functional antagonist as it can stimulate and block cholinergic function. Acts on nicotinic rec or parasympathetic and sympathetic autonomic ganglion, ^release of neurotransmitters such as dopamine, norepinehprine and serotonin.
Neurotransmitters and effectson Mood and Cognitive function
Mirtazapine
