Carbamazepine Flashcards
indications - epilepsy
focal and secondary generalised tonic clonic seizures
primary generalised tonic clonic seizures
indications - neuropathy
trigeminal neuralgia (pain in face)
diabetic neuropathy
indications - mental health
prophylaxis bipolar disorder unresponsive to lithium
indications - substance misuse
adjunct in acute alcohol withdrawal
3 CIs
Acute porphyrias; AV conduction abnormalities (unless paced); history of bone-marrow depression
vitamin D supplementation
MHRA advises consider vitamin D supplementation in patients who are immobilised for long periods or who have inadequate sun exposure or dietary intake of calcium.
withdraw immediately if (hint liver and blood)
Carbamazepine should be withdrawn immediately in cases of aggravated liver dysfunction or acute liver disease.
Leucopenia that is severe, progressive, or associated with clinical symptoms requires withdrawal (if necessary under cover of a suitable alternative).
skin disorder and HLA allele
The presence of HLA-B*1502 allele, particularly in individuals of Han Chinese or Thai origin, is strongly associated with an increased risk of Stevens-Johnson syndrome
The presence of HLA-A*3101 allele, particularly in individuals of European or Japanese origin, is associated with an increased risk of cutaneous adverse reactions but there are insufficient data to support pre-treatment screening. Consider use if potential benefit outweighs risk.
Seizure exacerbation - which types
Carbamazepine may exacerbate seizures in patients with absence or myoclonic seizures (including juvenile myoclonic epilepsy), tonic or atonic seizures, Dravet syndrome, Lennox-Gastaut syndrome, and myoclonic-atonic seizures.
enzyme inhibitor or inducer?
CRAP GPS
inducer which means it decreases the level of other drugs!
miconazole and carbamazepine interaction severe
Miconazole increases the risk of Carbamazepine toxicity when given with Carbamazepine. Manufacturer advises monitor and adjust dose.
interaction with MAOIs
Carbamazepine is predicted to increase the risk of severe toxic reaction when given with Phenelzine. Manufacturer advises avoid and for 14 days after stopping the MAOI.
Interaction with DOACs e.g. apixaban, rivaroxaban
Carbamazepine is predicted to decrease the exposure to Rivaroxaban. Manufacturer advises avoid unless patient can be monitored for signs of thrombosis.
Carbamazepine and Ulipristal (EHC Ellaone)
Carbamazepine decreases the efficacy of Ulipristal. Manufacturer advises avoid and for 4 weeks after stopping the enzyme inducing drug.
Interaction with CHC
Carbamazepine is predicted to decrease the efficacy of Combined hormonal contraceptives
Antiepileptic hypersensitivity syndrome associated with carbamazepine?
Yes
monitoring in pregnancy
Plasma-drug concentration should be monitored and may be maintained on the lower side of the therapeutic range provided seizure control is maintained.
Pre treatment screening - HLA allele
Test for HLA-B*1502 allele in individuals of Han Chinese or Thai origin, and consider testing in other at-risk Asian populations such as individuals of Filipino or Malaysian origin (avoid unless no alternative).
Therapeutic drug monitoring
Plasma concentration for optimum response 4–12 mg/litre (20–50 micromol/litre) measured after 1–2 weeks.
When to monitor levels of carbamazepine
after 1–2 weeks.
monitoring pt parameters
Manufacturer recommends blood counts and hepatic and renal function tests (but evidence of practical value uncertain).
treatment cessation for bipolar disorder
reduce the dose gradually over a period of at least 4 weeks.
pt and carer advice - Blood, hepatic, or skin disorders
Patients or their carers should be told how to recognise signs of blood, liver, or skin disorders, and advised to seek immediate medical attention if symptoms such as fever, rash, mouth ulcers, bruising, or bleeding develop.
toxicity signs - HANDBAG
hyponatraemia
ataxia
nystagmus
drowsiness
blurred vision
arrhythmias
GI disturbances
how to remember therapeutic range for carbamazepine
4-12
4 because carb
12 because carbamazepine almost 12 letters
