II. Mechanism of Action
A. Alter movement of Na, K, Ca & Mg ions
B. Stabilized & cell membranes & make cells less responsive
C. Decrease excitability & responsiveness of brain neurons
A. Status epileptics
2. Valproic acid
A. Prevention or control of seizure activity
B. Maintenance therapy for chronic recurring seizures
C. Acute treatment of convulsions
D. Status epilepticus
A. Drug allergy
1. Grapefruit juice
a. Increase levels
a. Decrease in half-life
B. Valproic acid
a. Increase CNS depression
a. Decrease levels
VII. Side Effects
a. Bone marrow suppression
i. Aplastic anemia
2. Stevens-Johnson syndrome
B. Valproic acid
2. Weight gain
C. Levetiracetam / Oxcarbazepine / Lamotrigine
D. Gabapentin / Pregabalin
1. Peripheral edema
3. Visual changes
Successful control of a seizure disorder hinges on selecting the appropriate drug class and drug dosage, the patient complying with the treatment regimen, and limiting toxicity.
Serum drug concentrations are useful guidelines in assessing the effectiveness of therapy. Maintaining serum drug levels within therapeutic ranges helps not only to control seizures but also to reduce adverse effects.
Welcome back and today we are going to discuss anticonvulsants.
There are various types of anticonvulsants. During a seizure, there can be a lack of oxygen to the brain. The longer the seizure, the longer the damage caused by the lack of oxygen. Status epilepticus is a term for seizures greater than 5 mins and are considered medical emergencies – these require the one types of medications shown here (with your top two being benzodiazepines – diazepam and lorazepam). Now, once the emergency has passed the focus is then using maintenance medications (the list to your right). These meds cover many drug classes with the overall goal of altering the brain’s electrolytes therefore calming excitability. Neurologists are commonly consulted to manage anticonvulsants as there are many drugs with many serious side effects. I’ve had many patients on carbamazepine and valproic acid with a goal of control or limiting their seizure activity so they can function in life. As mentioned earlier, the goal is acute treatment and control of convulsions (seizures) and epilepsy. We again are trying to decrease the excitability in the brain which is causing things to go haywire (things are too exciting). Have you seen someone during a seizure episode? It’s all excitement – violent movements and jerking, it can be quite scary. As a caregiver, they goal to support safety and airway, with a goal of termination of the episodes as fast as possible. The longer the episodes, the longer the damage. Contraindications include allergies and pregnancy (as some drugs have serious side effects that could harm the baby). Although risks and benefits must of evaluated – as multiple seizures will ultimately cause hypoxia and cause fetal harm as well. Typically a neurologist or fetal medicine provider will determine the safest course of action with a pregnant patient’s anticonvulsant options. Interactions are individualized and vary. Carbamazepine with taken with grapefruit juice will cause increases in anticonvulsant medication levels due to its rapid metabolism. This drug also interacts with warfarin, with it decreasing in the drug’s half-life (the drug leaves the body faster than expected). Now valproic acid with used with barbiturates will increase CNS depression – remember we are slowing things down, barbituates also slow things down. Lastly, we have gabapentin. Which when used with antacids will decrease medication levels. Now the level of seizure control is based on therapeutic levels so if those are altered, more seizures will occur – which is a bad thing!
Priority Nursing Concepts for a patient receiving anticonvulsant medications include cellular regulation and pharmacology.
Alright, let’s recap. Anticonvulsants will alter electrolytes in the brains in order to decrease excitability in neurons. Types of drugs are based on whether the provider is treating status epilepticus or general seizure control – they cover many drug classes. Indications are to treat and control seizure activity, status epilepticus and epilepsy. Contraindications are allergy and pregnancy based, as some medication can cause fetal harm. Interactions are drug-specific and include grapefruit juice, warfarin, antacids, and barbituates (depending on the drug). Always remember – the longer the seizures, the longer the damage. The goal is to control here. Now you know all there is to know about anticonvulsants. Now go out and be your best self and happy nursing!