Neuromuscular and neurological Flashcards
Levodopa is for
Parkinson’s disease
What does Levodopa do?
It’s the precursor of dopamine. Increase brain dopamine (DA) by crossing the BBB and being converted to DA to replenish depleted striata DA. It can be converted in the peripheral tissue so is usually administered with peripheral inhibitors to avoid AEs
Levodopa works with
Benserazide, carbidopa and entacapone (inhibit levodopa conversion to dopamine in peripheral tissues because it can’t cross the BBB as dopamine).
Amantadine (stimulate dopamine release)
Selegiline (inhibit the breakdown of dopamine)
Benserazide and carbidopa are
Inhibitors of decarboxylase and can’t cross the BBB. Given as fixed-dose combos
AEs of Levodopa:
Nausea, vomiting chemoreceptor zone (CTZ), orthostatic hypotension, involuntary movements (head, lips, tongue), agitation and confusion (due to the disease itself) and depression (may require antidepressants).
Entacapone is for
Parkinson’s disease
What does entacapone do
Inhibits catechol-O-methyltransferase (COMT- metabolises catecholamines like DA and levodopa)
Can entacapone cross the BBB
No
What does entacapone affect and do
Mainly the peripheral COMT and prolongs the clinical response to levodopa
AEs of entacapone:
Nausea and vomiting, diarrhoea, dyskinesia and drug-drug interactions.
What is amantadine for
Parkinson’s disease
What does amantadine do
It’s an antiviral used against some strains of bacteria. It increases DA release, blocks cholinergic receptors, and acts as an N-methyl-D-aspartate antagonist in the glutamatergic pathway from the subthalamic nucleus to globus pallidus.
AEs of amantadine
Nightmares, insomnia, hallucinations, dizziness, orthostatic hypotension and ankle oedema.
What is selegiline for
Parkinson’s disease
What is selegiline
A MAO type B inhibitor (MAO-B). Inhibition of MAO-B activity increase DA levels and may also block DA re-uptake. MAO-B is an enzyme that degrades DA particularly in the SN (serotoninergic neurons)
Selegiline is used with
Smaller doses of levodopa
AEs of selegiline
Dry mouth and a transient increase in liver enzymes
Medications of multiple sclerosis (MS) are for
Controlling symptoms (depression, spasticity). Antidepression for depression, diazepam for spasticity
For management of acute relapses of MS
Corticosteroids (PO or IV). E.g. methylprednisolone (IV) to shorten duration of acute relapse by inhibiting mediator synthesis, mast cell de-granulation, increases WBC, and fibroblasts and thus improves nerve conduction.
Interferon beta and glatiramer used for and what does it do
For MS and it’s to minimise disease progression, reduce the frequency of relapses, promote myelination, prevent de-myelination and disability.
How does interferon beta work?
It has an immunoregulatory action, thus decreases cytokine release, augments suppressor T cell function and increases the activity of macrophages and cytotoxic T cells
AEs of interferon beta
Influenza-type signs and symptoms that decrease with continued therapy (fever, joint, muscle pain, headache) and injection site reaction
How does glatiramer work?
Pharmacodynamics are poorly understood but it is thought that it blocks presentation of myelin antigens to T cells and induces suppressor T cells
AEs of glatiramer
Local effects (redness, pain, itching) and systemic effects (chest pain, palpitations, flushing)
What is fampridine for and what does it do?
For MS. A K+ channel blocker (SR, BD). It restores conduction in demyelinated axons by reducing current leakage from demyelinated neurons and thus improves walking speed.
Who is fampridine contraindicated in?
People with a history of seizures and renal insufficiency
AEs of fampridine:
Insomnia, dizziness, headaches and urinary tract infection (UTI)
What are anticholinesterases like neogesigmine (SC/IM) and pyridostigmine (oral) for and what do they do.
For myasthenia gravis. Help reduce degradation of ACh by inhibiting cholinesterase and enhances neuromuscular transmission. Thus, more ACh is available and its action is prolonged
AEs of anticholinesterases like neogesigmine and pyridostigmine:
Increased salivation, nausea, vomiting and diarrhoea
Corticosteroids for myasthenia graves used to
Decrease inflammation
Immunosuppressants for myasthenia gravis:
Ciclosporin and azathioporine
What does ciclosporin do
It’s a calcineurin inhibitor- it blocks the action of calcineurin in activated T cells. It prevents production of interleukin-2 and other cytokines which normally stimulate T cell proliferation and differentiation.
AEs of ciclosporin
GI disturbances and hirsutism
What does azathioprine do
Impairs lymphocyte proliferation, cellular immunity and antibody response
AEs of azathioprine
Thrombocytopenia, anaemia and leucopenia. Susceptibility to infection as well as liver and kidney dysfunction in higher doses.
