Levodopa: Drug Interactions – Parkinson's Disease Medications (Nursing)

00:01 Now there's some dangerous drug interactions and these are always important for nurses to know to keep their patients safe.

00:06 If you combine levodopa or levodopa/carbidopa with first generation antipsychotics, here's the problem.

00:15 First generation antipsychotics -- that was the first group of antipsychotics that were found - they block receptors for dopamine in the striatum.

00:23 Okay, that's a problem because we know that Parkinson's disease is an imbalance between acetylcholine and dopamine in the striatum.

00:33 So, if you give them a medication that blocks dopamine receptors, holy cow! You're definitely gonna decrease the therapeutic effects of levodopa because it doesn't matter how much dopamine you get into that brain, you've blocked the dopamine receptors with the first-generation antipsychotic.

00:50 Those medications can also have some responses of tardive dyskinesias and everything else.

00:54 A Parkinson's patient does not need that.

00:58 The other drug that would be dangerous is a MAO inhibitor.

01:01 Let me give you a tip though, right by MAO inhibitors just doesn't play well with others.

01:07 Yeah, I'll tell you what I mean.

01:09 If someone's on a MAO inhibitor for depression, it doesn't play well with hardly any other drug.

01:16 Levodopa is no exception.

01:17 If you have levodopa and MAO inhibitor, it can cause a hypertensive crisis so if the patient's taking a non-selective MAO inhibitor and they take levodopa or levodopa/carbidopa, holy cow! You're putting that patient in an increased risk for hypertensive crisis.

01:34 So dangerous drug interactions, first generation antipsychotics, and MAO inhibitors.

01:41 Now stop and pause for just a minute and without looking in your notes, can you walk through why a first-generation antipsychotic is dangerous with levodopa? Think through the mechanism of first-generation antipsychotics and its impact on Parkinson's.

01:58 Good. Now, check your answer and make sure you got it correct.

02:02 Say, that's a great strategy to take a pause, a break, and try to recall what you know about that information.

02:10 Now, levodopa/carbidopa can do some good things too if you give it with an anticholinergic medication.

02:17 Remember that was that 6th category that we've been discussing because anticholinergic medications - 'anti' means blocker, 'cholinergic' is a type of receptor.

02:28 Acetylcholine mediates or activates cholinergic receptors.

02:33 So, for blocking those receptors, the acetylcholine receptors were gonna help restore the balance of dopamine and acetylcholine cuz even though we technically have extra acetylcholine, we've blocked the receptors where it works so anticholinergic medications will help us restore some balance and it will actually enhance the responses to levodopa.