Medication adverse effects

Question 1

Phenytoin adverse effects

What is it primarily used for?

Answer 1

• Used in management of seizures
  (binds to sodium channels to increase refractory period)
• Induces P450 system

Effects
Acute - diplopia, nystagmus, slurred speech, ataxia

Chronic - Hirsutism, peripheral neuropathy

Teratogenic

Also pro-arrhythmogenic –> so cardiac monitoring required

Can cause megaloblastic anaemia

Question 2

Levodopa adverse effects

Answer 2

• Psychosis –> due to overstimulation of dopamine receptors (hallucinations and delusions)
• On-off effect –> Unpredictable changes between mobility and immobility
• Postural hypotension –> levodopa can inhibit noradrenaline release resulting in peripheral vasodilation

(Dyskinesa e.g. dystonia - muscle spasm, chorea, writhing movements - athetosis)

Question 3

Examples of ototoxic drugs

Answer 3

Aminoglycosides (gentamicin), furosemide, aspirin

Question 4

Ondansetron

Answer 4

Can result in polymorphic ventricular tachycardia

Question 5

Tetracycline (e.g. Doxycycline) Antibiotics

Answer 5

Increases the risk of idiopathic intracranial hypertension

Question 6

Triptans

Answer 6

Tightness of throat and chest

Question 7

When is metoclopramide CI in?

Answer 7

Parkinsons - Dopamine antagonist that readily crosses the BBB - can worsen parkinsons