EPILEPSY: SODIUM VALPROATE Flashcards

1
Q

Category

A

Category 2

Maintained on a specific brand based on clinical judgement (seizure frequency, treatment history etc.)

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2
Q

Indication

A
  • all forms of epilepsy
  • migraine prophylaxis
  • mania
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3
Q

MoA

A

Weak inhibitor of neuronal sodium channels.
Stabilises resting membrane potential.
Reduces neuronal excitability.

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4
Q

Patients under 55

male or female

A
  • SV should not be initated where alternative is available
  • If no alt = 2 specialists must independently document this
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5
Q

Contraindications

A
  • Acute porphyrias
  • Personal/ family history of severe hepatic dysfunction
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6
Q

Main risk

A

Highly teratogenic
1g = max in pregnancy
> = increased teratogenicity

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7
Q

What type of seizures is valproate used for?

A

1st line in all types of generalised seizures.

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8
Q

Sodium valproate + pregnancy

A

HIGHLY TERATOGENIC
- can lead to congenital malformations and neurodevelopmental disorders
- prescribers should NOT prescribe SV to females of childbearing potential

Contraindicated in pregnant women for BPD and only considered in epilepsy if no alternative.

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9
Q

When would SV be offered to women with childbearing potential

A
  • No other suitable treatment
  • Likelihood of pregnancy considered
  • PPP in place
  • Risks + benefits
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10
Q

Pregnancy Prevention Programme (PPP)

A
  • ONE highly effective method of contraception (e.g. IUD or implant) or TWO complementary forms of contraception
    including a barrier method.
  • Fully informed of the risks of use in pregnancy, and a signed risk acknowledgement form.
  • Seen annually by specialist for review.
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11
Q

PPP - Pharmacists role

A

Provide valproate patient card.
Remind pt. of risks in pregnancy/need for highly effective contraception.
Remind of need for annual specialist review
Dispense as whole pack - always give PIL
Refer/contact GP if pt.not taking highly effective contraception.

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12
Q

Major side effects to look out for

2

A
  1. Hepatic dysfunction
  2. Pancreatitis

report signs + withdraw treatment

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13
Q

Side effects

A

Hepatotoxicity
Blood disorders
Pancreatitis
Hyponatraemia
GI: D+N
Transient hair loss
Weight gain

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14
Q

Hepatotoxicity

A

Discontinue if abnormally prolonged prothrombin time
Monitor LFTs
* Persistent vomiting
* Abdominal pain
* Jaundice
* Malaise
* Drowsiness

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15
Q

Who is at increased risk of liver toxicity from SV?

A
  • Children < 3
  • Metabolic disorder
  • Organic brain disease
  • Severe seizures + mental retard
  • Multiple AEDs
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16
Q

Blood disorders

A

E.g. Leucopoenia, thrombocytopenia
Monitor - FBC
* Fever
* Sore throat
* Mouth ulcers
* Bruising or bleeding

17
Q

Pancreatitis

A

Abdominal pain
N + V

18
Q

Drugs that antagonise the anticonvulsant effect of sodium valproate

A

Quinolone
Mefloquine
SSRIs
Antipsychotics
TCA/related antidepressants

19
Q

Drugs that increase the risk of hepatoxicity with sodium valproate

A

Statins
Carbamazepine
Tetracyclines
Fluconazole/ Itraconazole
Isoniazid
Methotrexate/ Sulfasalazine

20
Q

Sodium valproate increases the concentration of what drugs?

A

Enzyme inhibitors = increases the drug concentration of other anti-epileptic drugs e.g. lamotrigine, phenobarbital

21
Q

Monitoring

A
  1. plasma-valproate conc
  2. LFT - before and every 6 months
  3. FBC
22
Q

What if liver enzymes are raised

A
  • transient
  • monitor until normal
  • discontinnue if abnormally long prothrombin time
23
Q

Sodium Valproate and
Vitamin D
supplementation?

A

MHRA advises
* vitamin D supplementation
* immobilized for long periods or
* inadequate sun exposure or dietary intake of calcium