Neurological drugs

Question 1

2 examples of L-dopa/peripheral decarboxylase inhibitors?

Answer 1

Co-beneldopa (levodopa and benserazide) and Co-carledopa (levodopa and carbidopa)

Question 2

How do L-dopa/peripheral decarboxylase inhibitors work?

Answer 2

Crosses BBB and is converted by dopa decarboxylase to replace deficient dopamine in the basal ganglia. The non-L-dopa component of the drug reduces peripheral side effects

Question 3

L-dopa/peripheral decarboxylase inhibitors are used in Parkinson’s disease, in what eye condition should they not be given?

Answer 3

Closed-angle glaucoma

Question 4

Why can’t dopamine itself be used as a drug in Parkinsonism disorders

Answer 4

Doesn’t cross BBB

Question 5

How should drugs used to treat Parkinson’s be discontinued?

Answer 5

Gradually

Question 6

5 examples of anti-convulsants, each with different mechanism of action*?

Answer 6

Phenytoin, carbamazepine, sodium valproate, lamotrigine, levetiracetam

Question 7

How does phenytoin work?

Answer 7

Blocks voltage gated Na+ channels preventing spread of epileptic discharges

Question 8

Indications for phenytoin use?

Answer 8

Status epilepticus, tonic-clonic seizures, focal seizures

Question 9

What side effects effecting the face can result from phenytoin use?

Answer 9

Facial coarsening, gingival hypertrophy and tenderness, rash, acne, hirsutism

Question 10

Why should phenytoin be withdrawn gradually?

Answer 10

Abrupt withdrawal can precipitate status epilepticus

Question 11

How does carbamazepine work?

Answer 11

Increases GABA mediated inhibitory CNS transimission, reduces electrical excitability of cell membranes by blocking Na+ channels

Question 12

Indications for carbamazepine?

Answer 12

Tonic-clonica and partial seizures, trigeminal neuralgia, bipolar prophylaxis, adjunct in acute alcohol withdrawal, diabetic neuropathy

Question 13

Contraindications to carbamazepine?

Answer 13

AV node conduction abnormalities, history of bone marrow depression, acute porphyria

Question 14

How does sodium valproate work?

Answer 14

Increases GABA content of the brain by inhibiting GABA transaminase, preventing GABA reuptake. Also decreases conc. of aspartate (an excitatory neurotransmitter).

Question 15

Indications for sodium valproate?

Answer 15

All forms of epilepsy, migraine prophylaxis, mania

Question 16

What is the result of giving 2 or more anticonvulsants?

Answer 16

Increased anticonvulsant effects and sedation

Question 17

How does lamotrigine work?

Answer 17

Blocks voltage gated Na+ channels, inhibits repetitive firing of neurones and inhibits glutamte release, preventing epileptic seizures

Question 18

Indications for lamotrigine?

Answer 18

Focal and tonic-clonic seizures, Lennox-Gastout syndrome seizures, absence seizures in kids, prevention of depressive episodes in Bipolar Affective Disorder

Question 19

When using lamotrigine, why is it important for patients to spot signs of skin disorders?

Answer 19

Could precede Stevens-Johnsons or toxic epidermal necrosis

Question 20

How does levetiracetam work?

Answer 20

Partially inhibits Ca++ channels, partially reverses reductions in GABA currents

Question 21

Indications for levetiracetam?

Answer 21

Focal seizures, myoclonic seizures

Question 22

What is the interaction of levetiracetam and methotrexate?

Answer 22

Reduces methotrexate clearance so need to monitor levels