Lamotrigine and zonisamide affect both Na+ and Ca++ channels.
Ethosuximide and pregabalin affect calcium channels.
Vigabatrin is used as an adjuct therapy for infantile seizures.
Sodium valproate increases GABA levels by decreasing breakdown.
GABA receptor upregulators: ❌. - Examples: ❌ - Action: Enhances GABA neurotransmission, ❌ GABA neurotransmission, suppresses ❌ transmission throughout the CNS - Use: all forms of epilepsy EXCEPT ❌ epilepsy; status epilepticus, phenobarbitol 1st -line therapy for ❌ - Pros: Oldest prescribed AED; WHO list; CHEAP; long ❌ - Cons: CNS ❌; phenobarbitol - relatively-❌ therapeutic window; substance ❌ issues; CYP inducer
Zonisamide: Action: Blocks ❌ ion channels; binds and activates GABA receptor Use: mono- and adjunctive therapy for focal epilepsy; Lennox-Gastaut syndrome; Parkinson disease Powerful antiepileptic, costly, ❌ available in NZ.
Topiramate - Action: Blocks ❌ channels; potentiates GABA ❌ and effect; inhibits carbonic anhydrase - Use: mono- and adjunctive therapy for multiple forms of epilepsy; migraine prophylaxis, idiopathic intracranial hypertension - Pros: No serum monitoring; relatively ❌ - Cons: 20+yrs of use; CNS ❌; renal and ophthalmologic complications; side effects; unclear regarding pregnancy/lactation risk
Retigabine (Onelink) Action: Activates ❌ ion channel to return depolarised neurons to ❌ state and reducing neuronal excitability Use: ❌ management of focal epilepsy Pros: Quick ❌; unique ❌ of activity Cons: cardiac and ophthalmologic complications; side effects; costly
Racetams - Examples: Levetiracetam (Keppra), Piracetam (Nootropil) - Action: Block ❌ ion channels; modulate AMPA receptors - Use: focal epilepsy (mono- and adjunctive therapeutic uses); generalised GTC and myoclonic epilepsy - Pros: Wide therapeutic use in epilepsy (L); limited ❌ effects
DA agonists - ❌-ergot derivatives: e.g. Pramipexole, Ropinirole • ❌ tolerated (but still nausea, hypotension, constipation) • Dyskinesias • Sudden onset of ❌ - caution re: driving • Adjunct: ❌
❌ (specialist supervision) • Good for unpredictable ‘off’ periods, ❌ administration • 2 days pre-treatment with ❌
Amantadine: • ❌ DA agonist • Modest anti-PD effect • Tolerance • Confusion/❌ • Useful for ❌ in late disease Unwanted Effects: ❌ (decrease dose in renal impairment)
Selective MAO-❌ inhibitors: E.g. ❌ and rasagiline • Decrease ❌ of DA in ❌ • Prolong ❌ of action • First used as adjunct to L-DOPA, to decrease dose requirement (1/3) • ‘L-DOPA sparing’ • Mow also used with DA agonists • Decreases end-of-dose ❌ • UEs: Nausea, ❌ mouth, dyspepsia, constipation, ❌ (common)
Inhibition of cholinergic activity - Anti❌ drugs e.g. Benztropine (benatropine), ❌ • Decrease relative ❌ • Little effect on ❌ • Modest effect - ❌ (excessive salivation) Unwanted effects: - (peripheral) worsen PD-related ❌ mouth. Also ❌ vision, urinary ❌. - (Central) ❌ restlessness (elderly)
Drug-induced Parkinsonism - ❌% of PD. ❌>men.
HIGH RISK 1. Dopamine ❌:
Antipsychotics - Typicals e.g. ❌ Atypicals ((lower incidence): e.g. ❌
❌ - e.g. metoclopromide
Methyldopa (centrally acting antihypertensive) is a dopamine depleter.
Which of these drug classes is not an intermediate risk for drug induced PD?
Calcium channel blockers eg verapamil, diltiazem
Mood stabilisers e.g. sodium valproate, lithium
Selective serotonin reuptake inhibitors e.g. fluoxetine, escitalopram
