Neuro medications Flashcards
How does sodium valproate work to treat seziures?
Increases the activity of GABA, which has a relaxing effect on the brain
Notable side effects of sodium valporate?
Teratogenic so patients need careful advice about contraception It must be avoided in girls or women unless there are no suitable alternatives and strict criteria are met to ensure they do not get pregnant)
Liver damage and hepatitis
Hair loss
Tremor
Notable side effects of carbamazepine
Agranulocytosis
Aplastic anaemia
Induces the P450 system so there are many drug interactions
Notable side effects of phenytoin?
Folate and vitamin D deficiency
Megaloblastic anaemia (folate deficiency)
Osteomalacia (vitamin D deficiency)
Ethosuximide notable side effects?
Night terrors
Rashes
Lamotrigine notable side effects?
Stevens-Johnson syndrome or DRESS syndrome. These are life threatening skin rashes.
Leukopenia
Sodium valproate is first line for most forms of epilepsy except for?
Focal seizures (carbamazepine)
How do levodopa + peripheral decarboxylase inhibitors treat Parkinson’s?
Levodopa + decarboxylase inhibitor - synthetic dopamine boosting dopamine levels used in combination with peripheral decarboxylase inhibitors to reduce levodopa breakdown in the BODY before it crosses BBB. Most effective treatment but becomes less effective over time, often reserved for when other treatments have failed.
- Co-benyldopa (levodopa and benserazide)
- Co-careldopa (levodopa and carbidopa)
Absorbed by active transport
How do COMT inhibitors treat Parkinson’s?
COMT (catechol-O-methyl transferase) inhibitors - taken WITH levodopa and decarboxylase inhibitors (not used as monotherpaies) to slow down levodopa breakdown in the peripherary (doesn’t cross BBB) and extend the effective duration by inhibiting the COMT enzyme, which metabolises levodopa in the body and brain.
More L-DOPA into the body
Prolongs motor response to L-Dopa - reduces symtpoms of wearing off
- entacapone
- opicapone
- tolcapone (crosses BBB but main action in periphary, monitor liver function as hepatotoxic)
How do dopamine agonists treat Parkinson’s?
Dopamine agonists - mimic dopamine in basal ganglia and, stimulate dopamine receptors, less effective than levodopa in reducing symptoms. Used to delay the use of levodopa and are then used in combination with levodopa to reduce the dose required for symptom control.Similarly to dopamine agonists, they are usually used to delay the use of levodopa and then in combination with levodopa to reduce the required dose.
Egot derived: (no longer used)
-Bromocryptine
-Pergolide
-Carbergoline
Non ergot:
-Ropinirole
-Pramipexole
Patch:
- Rotigotine
S/C
- Apomorphine (rescue therapy)
How do monoamine oxidase B inhibitors treat Parkinson’s?
Monoamine Oxidase enzymes break down neurotransmitters such as dopamine, serotonin, and adrenaline.
Monoamine oxidase-B is specific to dopamine (at low doses) so inhibiting this enzyme helps increase circulating dopamine
Predominates in dopamine containing regions in brain
- Selegiline
- Rasagaline
- Safinamide
Smooths out motor response, prolongs action of L-DOPA but can be used alone, (may be neuroprotective)
Notable side effect of dopamine agonists (ergot derived)?
Pulmonary fibrosis with prolonged use (hence no longer used)
What is the main side effect of too high a dose of levodopa?
Dyskinesias (abnomal movements associated with excessive motor activity), e.g:
- Dystonia (excessive muscle contractions lead to abnormal postures of exaggerated movements)
- Chorea (abnormal involuntary movements that can be jerking and random)
- Athetosis (involuntary twisting or writhing movements usually in the fingers, hands or feet)
Nausea/anorcia
Psychosis - schizophrenia-like side effects
Hallucinations/delusion/paranoia
Tachycardia
How do pyridostigmine and neostigmine treat myasthenia gravis?
Pyridostigmine - oral - mainstay
Neostigmine - oral and IV preperations - quicker action duration up to 4 hours
They are reversable acteylcholinesterase inhibitors, increasing the amount of Ach in the neuromuscular junction, meaning it is more likely to engage with the remaining receptors and improving symptoms.
- Enhance neuromuscular transmission
- Skeletal and smooth muscle action
What can be used to suppress the production of antibodies in myasthenia gravis?
Prednisolone
Azathioprine
Rituximab (if certain criteria met and standard treatment not effective) - targets B cells and reduced the production of antibodies
How does beta interferon (DMT) work?
Interferon beta balances the expression of pro- and anti-inflammatory agents in the brain, and reduces the number of inflammatory cells that cross the blood brain barrier. Overall, therapy with interferon beta leads to a reduction of neuron inflammation.
Teriflunomide mechanism of action (DMT)?
Reduces over activation of the immune system by reducing number of B cells and T cells
Natalizumab mechanism of action (DMT)?
Natalizumab is a monoclonal antibody that binds to alpha-4 integrin receptors on endothelial cells lining blood vessels.
DMDs in pregnancy?
No disease modifying drug (DMD) is proven to be safe during pregnancy, however there is increasing evidence that some are less risky than others. There is a growing body of evidence to suggest that exposure to the beta interferon drugs or glatiramer acetate (eg Avonex, Betaferon, Rebif, Extavia or Copaxone), does not change the overall risk to the pregnant woman or baby
Beta interferon has one of the lowest risks of side effects of the DMTs, but what are the possible side effects?
Depression
Up to two days after injection: flu like symptoms, chills, fevers, heacaches, muscle aches
Possible side effects of Teriflunomide
headaches, diarrhoea or feel sick. Your hair might get thinner but it grows back after six months
Natalizumab has a relatively high side effect profile compared to other DMTs, including what?
hives (itchy skin)
headache
shivers
stomach upset
joint pains
sore throat
feeling sick, tired or dizzy.
Side effects of monoxidase B inhibitors?
Seritonin syndrome if used in combination with other MAO inhibitors
Dry mouth, dizziness, fainting
Side effects of COMT inhibitors?
Pulmonary fibrosis, irregular HR, tachycardia, rapid weight gain
Levetiracetam: indication, side effects and contraindications, interactions and blood monitoring.
Indication: Focal seziures (monotherapy or adjunctive), myoclonic and tonic clonic seizures (adjunctive therapy)
Side effects and contraindications: Drowsiness, headache, nose and throat symptoms, QT prolongation, N&V, diahorrea, appetite loss, fatigue, diziness, skin rash, vertigo, cough, mood changes, unsteady/shakey
Interactions: Methotrexate (DECREASES CLEARENCE), CNS depressants
Blood monitoring: Not routinley required
