NEUROLOGY DRUGS Flashcards
PARACETAMOL
I: Acute and chronic pain
Fever
MOA: MOA of paracetamol is poorly understood. Paracetamol is a weak inhibitor of cycolo-oxygenase (COX)
SE: Few side effects. In overdose, paracetamol can cause liver failure
C: Chronic excessive alcohol use, malnutrition, low body weight (<50kg) and severe hepatic impairment
KI: CYP inducers (phenytoin and carbamazepine) increase rate of NAPQI production and risk of liver toxicity after paracetamol overdose
PC: Not to exceed the recommended maximum daily dose.
M: Efficacy - enquiry about symptoms and do a blood test after overdose for (INR, alanine aminotransferase activity, creatinine concentration)
OPIOIDS (WEAK/MODERATE)
Tramadol, Codeine, Dihydrocodeine
I: Mild-Moderate pain
MOA: They are metabolised in the liver to produce small amounts of morphine. These metabolites are stronger agonists of opioid (mu) receptors which accounts for most of the analgesic effect
SE: Nausea, drowsiness, neurological and respiratory distress. Codeine and dihyrdocodeine must never be given IV - can cause severe reaction.
CI: Avoid tramadol in Uncontrolled epilepsy
C: Significant respiratory disease, dose ↓ in renal, hepatic impairment and in elderly.
KI: Other sedating drugs (antipsychotics, benzodiazepines), tramadol should not be used with other drugs that lower the seizure threshold (antipsychotics) and can increase risk of serotonin syndrome when taken with other serotonergic drugs.
M: Efficacy of analgesics - symptom enquiry.
Acute: review response to analgesia 1-2 hours after oral dose
Chronic: review after 1-2 weeks to assess the need to step up or down the
analgesic ladder
OPIOIDS (STRONG)
Morphine, Oxycodone
I: Acute severe pain, relief of chronic pain, end of life care, acute pulmonary oedema
MOA: Activation of opioid u receptors. They reduce sympathetic nervous system (fight or flight) activity.
SE: Respiratory depression, in ↑ doses cause neurological depression. Nausea and vomiting, pupillary constriction, constipation, itching, tolerance, dependence
CI: Avoid opioids in biliary colic (worsen pain). Do not give opioids in resp failure except under senior guidance (palliative care)
C: Dose ↓ in hepatic failure, renal impairment, elderly.
PC: offer anti emetic to settle nausea and vomiting
M: Acute pain- Review analgesia response within an hour
Chronic pain- review after couple of weeks to assess the need to step up or down the analgesic ladder and/ or specialist referral
CARBAMAZEPINE
I: Seizure prophylaxis in Epilepsy, Trigeminal Neuralgia (1st line to control pain and reduce frequency and severity of attacks)
SE: GI upset (nausea and vomiting) , neurological effects (dizziness and ataxia), hypersensitivity, oedema, hyponatreamia.
CI: Antiepileptic hypersensitivity syndrome
C: Women with epilepsy planning pregnancy should discuss treatment with specialist and start taking high dose folic acid supplements before conception as carbamazepine is associated with neural tube defects and cleft palate
KI: Drugs metabolised by CYP enzymes - reduces efficacy (warfarin, oestrogens and progesterone)
Side effects are increased with CYP inhibitors (macrolides)
Complex interactions occur with other antiepileptic drugs (Lamotrigine) - altered drug metabolism
Efficacy is reduced by drugs that lower seizure threshold (Antipsychotics, Tramadol)
PC: Must not drive unless they have been seizure free for 12 months and for 6 months after changing or stopping treatment.
M: Efficacy- Comparing seizure frequency before and after starting treatment / dose adjustment.
Safety - ask patient to report any unusual symptoms
Bloods should be taken immediately before next dose when carbamazepine concentrations should be 4-12mg/L.
VALPROATE
Sodium Valproate, Valproic Acid
I: Seizure prophylaxis in epilepsy, Established convulsive status epilepticus (when not responding to benzodiazepines) and bipolar disorder
SE: GI upset, neurological and psychiatric effects, thrombocytopenia, hair loss
CI: Women of child bearing age, conception, first trimester of pregnancy - associated with fetal abnormalities and hepatic impairment
C: Dose ↓ severe renal impairment
KI: Increases risk of toxicity with lamotrigine and warfarin. CYP inducers (phenytoin, carbamazepine) increases risk of seizures. Increased side effects with CYP inhibitors (macrolides). Efficacy of antiepileptic drigs are reduced by drugs that lower seizure threshold (tramadol)
PC: Take tablet with food to reduce indigestion, no valproate with contraception /pregnancy. Must not drive unless they have been seizure free for 12 months and for 6 months after changing or stopping treatment.
LAMOTRIGINE
I: Seizure prophylaxis, add on therapy in focal seizures, generalised tonic-clonic and absence seizures
SE: Headache, drowsiness, irritability, blurred vision, GI symptoms, skin rash, hypersensitivity
CI: Hypersensitivity
C: Dose ↓ in moderate/severe hepatic impairment
KI: CYP inducers can cause lamotrigine concentration leading to treatment failure
PC: If they miss a dose, remember to take it ASAP. Do not stop treatment abruptly as it can cause rebound seizures. Seek immediate help if they develop rash, ulcerm swollen glands, fever. Must not drive unless they have been seizure free for 12 months and for 6 months after changing or stopping treatment.
M: Efficacy- Comparing seizure frequency before and after starting treatment / dose adjustment.
Safety - ask patient to report any unusual symptoms
LEVETIRACETAM
I: Seizure prohylaxis in epilepsy. Add on therapy for focal seizures (if carbamazepine or lamotrigine does not work), myoclonic, generalised tonic-clonic seizures. Established convulsive status epilepticus
SE: generally well tolerated drug. May be some SE such as drowsiness, weakness, headaches
C: Dose ↓ in renal impairment
PC: If they miss a dose, remember to take it ASAP. Do not stop treatment abruptly as it can cause rebound seizures. Seek immediate help if they develop rash, ulcerm swollen glands, fever. Must not drive unless they have been seizure free for 12 months and for 6 months after changing or stopping treatment.
M: Efficacy- Comparing seizure frequency before and after starting treatment / dose adjustment.
Safety - ask patient to report any unusual symptoms
BENZODIAZEPINES
I: First line management for seizures, status epliepticus, alcohol withdrawal reactions. Sedation for interventional procedures, short term treatment of severe anxiety or insominia.
SE: Drowsiness, sedation, coma, benzodiazepine overdose can lead to airway obstruction and death. if used repeatedly, it can cause dependence. Abrupt cessation then produces a withdrawal reaction.
CI: respiratory impairment, neuromuscular disease (myasthenia gravis), liver failure (can lead to hepatic encephalopathy)
C: Dose ↓ in elderly
KI: CYP inhibitors can increase the effect of benzodiazepines
PC: dont drive or operate heavy machinery after taking drug, can cause them to feel sleepy the next day, for insominia and anxiety treatment - short term. avoid dependence by minimising daily use
M: Close monitoring of vitals for IV use (seizures. alcohol withdrawal, sedation).
Symptom enquiry for insominia and anxiety
ANTI EMETICS
Metoclopramide, Cyclizine, Promethazine, Prochlorperazine, Chlorpromazine, Ondansetron
Triptans
Sumatriptan
I: Acute migraine with or without aura (when painkillers or NSAIDS dont work)
SE: pain or discomfort in the chest or throat, nausea+vomiting, dizzy, facial flushes
CI: coronary artery disease (angina, MI, arrythmia), cerebrovascular disease (TIA, stroke), pregnancy/breastfeeding, hemiplegic, basilar migraines
KI: Can increase serotonin toxicity and serotonin syndrome when given with other serotonergic drugs (tramadol, monoamine oxidase inhibitors)
PC: Dont take it to prevent an attack, only take it when it comes on. Do not take another dose if the triptan does not work. can be taken in combination with painkillers/ antiinflammatory. Keep a migraine diary. If they take too much sumatriptan, call 111 - can cause fainting, slow HR, loss of bladder and bowel control.
M: Follow up appointment to see if triptan is working (first time pts)
