We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 06 October 2020
THERAPEUTICS
Brands
• Nitoman, Xenazine
Generic?
• No
Class
• Monoamine-depleting agent
Commonly Prescribed for
(FDA approved in bold)
• Chorea in Huntington's disease (HD)
• Tardive dyskinesia
• Psychosis
• Hemiballism
• Dystonia (especially tardive)
• Myoclonus
• Gilles de la Tourette syndrome (GTS) or tics
• Hypertension
How the Drug Works
• Depleting agent that reversibly inhibits vesicular monoamine transporter type 2 (VMAT2) resulting in depletion of monoamines, primarily dopamine but less effect on others (norepinephrine, serotonin, and histamine), from nerve terminals. It also weakly blocks postsynaptic D2 receptors. Effectiveness is likely related to dopamine depletion. Sedation and depression are probably due to histamine and serotonin/norepinephrine depletion, respectively
How Long Until It Works
• Rapid onset, lasting 5–6 hours
If It Works
• In neurological conditions, continue to assess effect of the medication, determine if still needed, and adjust to optimal dose
If It Doesn't Work
• Chorea: consider benzodiazepines and AEDs (valproate). Neuroleptics are usually effective. Reserpine is an alternative depleting agent
• Generalized dystonia: anticholinergics, baclofen, or benzodiazepines may be effective. Surgical treatments (including pallidotomy, thalamotomy, deep brain stimulation, myotomy, rhizotomy, or peripheral denervation) are reserved for refractory cases
• GTS/tics: neuroleptics and α2-adrenergic agonists are often effective
Best Augmenting Combos for Partial Response or Treatment-Resistance
• Chorea: combine with AEDs, neuroleptics, or benzodiazepines
• Dystonia: combine with anticholinergics or benzodiazepines
• GTS/tics: combine with neuroleptics for refractory cases
Tests
• At doses of 50mg or greater, test patients for the CYP2D6 gene to determine if they are poor, intermediate, or extensive metabolizers
ADVERSE EFFECTS (AEs)
How the Drug Causes AEs
• Related to monoamine depletion
Notable AEs
• Drowsiness, fatigue, dizziness, depression, anxiety, insomnia
• Parkinsonism, akathisia, orthostatic hypotension, nausea
• Upper respiratory tract infection, dyspnea, dysuria
• Slight increase in liver function tests
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
