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Flashcards in Side effects Deck (8)
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1

Levodopa ADR

• ADRs

– Nausea / vomitting
– Orthostatic hypotension
– Drowsiness, sudden sleep onset
– Hallucinations, psychosis
– Dyskinesias
• Usual onset : within 3-5 years of initiating treatment with levodopa

Dyskinesias
– Involuntary, uncontrollable
– Twitching, jerking
– Not tremor
– Peak dose dyskinesia
– Dystonia

2

Levodopa DDI

• Pyridoxine
– Cofactor for dopa decarboxylase
– Generally not a problem if levodopa is administered with a DCI but…
– unless on ?High dose B6 for haematological problems or in high potency vit B6 ----> need do med review to confirm

• Iron
• Protein
Both can bind to LD and decrease absorption. need space 2 hr apart. Move protein to night time.


• Antidopaminergic drugs
–Metoclopramide, prochlorperazine
– Antiemetic of choice in PD = domperidone
– 1st generation antipsychotics
– Risperidone --> ~2mg can exhibit EPSE

• Volatile general anaesthetics – Sevoflurane, halothane • Nonselective MAOis

3

Dopamine agonists – adverse effects

Dopaminergic - peripheral
• Nausea, vomitting
• Orthostatic hypotension
• Leg oedema

Dopaminergic - central
• Hallucinations (usually visual > auditory)
• Somnolence, day-time sleepiness
• Compulsive behaviours – Gambling, shopping, eating, hypersexuality

Non-dopaminergic adverse effects
• Fibrosis
– Pulmonary, pericardiac, retro-peritoneal
– May be partially reversible upon withdrawal
– Lower risk with non-ergot agents

• Valvular heart disease
– Incidence appears to be greater with ergot-derived agents

4

• MAOI Drug interactions

• MAOI Drug interactions
– SSRIs, SNRIs, TCAs
• Washout periods recommended

– Pethidine , tramadol,
– Linezolid
– Dextromethorphan
– Dopamine
– Sympatomimetics : nasal decongestants e.g. pseudoephedrine, phenylephrine
– Another MAOi

5

MAOI FDI

Food interactions

• Chemical of concern = tyramine
– Metabolised by both MAO-A and MAO-B
• No firm guidelines regarding the necessity for dietary restrictions
– Europe AND SIngapore – no restriction
– US – absolute restrictions hold for aged cheeses & meats, draft beer, fermented food (sauerkraut, kimchi), Marmite, banana peel.

• In practice, patients should be advised to avoid such foods

6

Entacapone • Drug interactions and ADR

– iron, calcium,
– Avoid concurrent nonselective MAOi (but safe with MAOBi, caution with selective MAO-Ai)
– any catecholamine drug
– Enhance anticoagulant effect of warfarin

• Diarrhoea, urine discolouration (orange)
• May cause dyskinesia upon initiation
– May require a DECREASE in levodopa dose

• May also potentiate other dopaminergic effects
– Orthostatic hypotension, nausea/vomitting

7

Amantadine • Adverse effects

– Nausea, light-headedness, insomnia, confusion, hallucinations, livedo reticularis

8

Drug - induced parkinsonism

• Dopamine depleting drugs
– Tetrabenazine

• Others (?MOA)
– Sod valproate
– Lithium
– Lamotrigine
– Cinnarizine