Neurology

Question 1

What is Carbamazepine used to treat?

Answer 1

• Seizure prophylaxis in epilepsy
• First-line prophylaxis of generalised tonic-clonic and focal seizures
• To control pain and reduce frequency and severity of attacks in trigeminal neuralgia

Question 2

What are the main side effects of Carbamazepine?

Answer 2

Common:
- Nausea
- Vomiting
- Neurological effects e.g. dizziness and ataxia
- Oedema
- Hyponatremia (antidiuretic-hormone life effect)

• Hypersensitivity(10%) most mild maculopapular rash (most common presentation)

Antiepileptic hypersensitivity syndrome (1 in 5000)
- Severe skin reactions (e.g. Stevens-Johnsons syndrome)
- Fever
- Lymphadenopathy

Question 3

What are the key contraindications of Carbamazepine?

Answer 3

In utero associated with:
- Neural tube defects
- Cardiac abnormalities
- Urinary tract abnormalities
- Cleft palate

Use with caution in:
- Pregnancy (taking folic acid before conception)
- Hepatic impairment
- Renal impairment
- Cardiac disease

Contraindications:
- Prior antiepileptic hypersensitivity syndrome (due to potential cross-sensitivity)

Question 4

What other drugs does Carbamazepine interact with?

Answer 4

Induces CYP enzymes which reduces the plasma concentrations and efficacy of drugs metabolized by CYP enzymes e.g.:
- Warfarin
- Oestrogens
- Progesterons

• Conc and adverse effects increased by CYP inhibitors (e.g. macrolides)
• With other antiepileptic drugs (e.g. Lamotrigine) due to altered drug metabolism
• Efficacy reduced by drugs that lower the seizure threshold e.g.:
• Antipsychotics
• Tramadol

Question 5

What are the main indications for Valproate?

Answer 5

Seizure prophylaxis in epilepsy. 1st line

Established convulsive status epilepticus
- Only cases that have not responded to treatment with a benzodiazepine

Bipolar disorder:
- Acute treatment of manic episodes
- Prophylaxis against recurrence

Question 6

What are the main/ common side effects of Valproate?

Answer 6

VALPROATE MEMORY

V- vomiting
A- alopecia
L- Liver toxicity
P- pancreatitis/ pantctopenia
R- retention of fat (weight gain)
O- oedema
A- appetite increase
T- tremor/ throbocytopenia
E- enzyme inducer

Question 7

Whom is Valproate contraindicated in?

Answer 7

• Greatest risk of fetal abnormalities, thus teratogenic:
• Women of child-bearing age
• Conception
• 1st trimester of pregnancy
• Avoid in severe hepatic impairment
• Reduce dose in severe renal impairment

Question 8

What are the Key drug interactions of valproate?

Answer 8

Inhibits hepatic enzymes which increases plasma concentration and risk of toxicity with:
- Lamotrigine
- Drugs metabolized by CYP enzymes e.g. Warfarin

Conc decreased, and risk of seizures increased by:
- CYP inducers (e.g. carbamazepine, phenytoin)
- Carbapenems

CYP inhibitors (e.g. macrolides, protease inhibitors) increase the risk of adverse effects

Efficacy reduced by drugs that lower the seizure threshold (e.g. antipsychotics, tramadol)

Question 9

What are the main indications of Lamotrigine?

Answer 9

Seizure prophylaxis in epilepsy
- First-line monotherapy or add-on therapy in focal seizures

• Bipolar depression, but not mania or hypomania

Question 10

What are the main side effects of Lamotrigine?

Answer 10

• Headaches
• Drowsiness
• Irritability
• Blurred vision
• Dizziness
• Nausea
• Vomiting
• Minority develop a skin rash within a few weeks of starting treatment
  ^^ like Carbamazepine

Question 11

Whom is Lamotrigine contraindicated in?

Answer 11

Avoid in pts with:
- Prior history of hypersensitivity reactions to other antiepileptic drugs (due to cross-reactivity)

Reduce dose in:
- Moderate or severe hepatic impairment

Question 12

What other drugs does Lamotrigine interact with?

Answer 12

Drugs that induce glucuronidation ( which causes conc to fall causing treatment failure) e.g:
- Carbamazepine
- Phenytoin
- Oestrogens
- Rifampicin
- Protease inhibitors

• Valproate inhibits glucuronidation  increased lamotrigine conc  increases the risk of toxicity
  ^^can also increase the risk of severe hypersensitivity reactions when co-prescribed

Question 13

What are the main indications of Levetiracetam?

Answer 13

Seizure prophylaxis in epilepsy
- If carbamazepine/ lamotrigine are unsuitable/untolerated option for monotherapy or add-on therapy in focal seizures

• Selected cases of established convulsive status epilepticus that have not responded to benzodiazepine

Question 14

What are the main side effects of Levetiracetam?

Answer 14

Common:
- Drowsiness
- Weakness
- Dizziness
- Headaches

Less common:
- Mood disturbances
- Psychiatric adverse effects

Rare:
- Suicidal ideation
- Serious hypersensitivity reactions

Question 15

What is the key contraindication when giving Levetiracetam?

Answer 15

Renal impairment

Question 16

What are triptans indicated in?

Answer 16

• Reduce the duration and severity of headache in acute migraine.

Question 17

What are the main side effects of triptans?

Answer 17

Common:
- Pain or discomfort in the chest and throat (can be intense but should resolve quickly)
- Nausea
- Vomiting
- Tiredness
- Dizziness
- Transient high BP

Rare:
- MI

Question 18

Whom are triptans contraindicated in?

Answer 18

Due to the risk of acute vascular events, contraindicated in pts with:
- Coronary artery disease (e.g. angina, MI)
- Cerebrovascular disease (e.g stroke)

• Ps with hemiplegic
• Pts with basilar migraines

Question 19

What other drugs does triptans interact with?

Answer 19

When given with other serotonergic drugs e.g. monoamine oxidase inhibitors, tramadol, SSRIs and tricyclic antidepressant, increases the risk of:
- Serotonin toxicity
- Serotonin syndrome