Explain The Mechanism of Action Amphetamine.

1. Explain the mechanism of action amphetamine.
According to Stahl (2021) the mechanism of action for amphetamine vs methylphenidate differ and the way amphetamine works it can have abuse potential
when taken at higher doses. Amphetamine works by being a competitive inhibitor at the dopamine transporter (DAT), it will displace the dopamine and the
amphetamine will be transported back into the cell. Once inside it will also act upon the VMAT also displacing the dopamine to be transported into storage.
When these occur it leads to excess amounts of dopamine free intracelluraly at which point it will spill out of the cell via DA channels or by reversing DAT
leaving more DA available in the synapse (Stahl, 2021). When this medication is taken at high doses the amount of DA in the synapse increases which will
then lead to the sence of euphoria which can lead to abuse.
Alpha-2 agonists are also used in the treatment of ADHD. For which symptoms are the most effective? Who might be an ideal candidate for monotherapy?
Alpha-2 agonists (a2) such as guanfacine and clonidine are two a2 agonists used in psychiatry to treat ADHD. The symptoms they are helpful in treating are
inattention, hyperactivity, impulsivity, and oppositional behaviors (Stahl, 2021). There are recommendations for both monotherapy and adjunctive therapy to a
stimulant. According to Stahl (2021) these medications used in patients with inattention, hyperactivity and impulsivity can be tried o on monotherapy. For
patients with behavioral concerns the recommendation would be to use is adjunctively with a stimulant.
Read the following scenario. There is no “right answer.” Please support your answer with evidence
A college student presents to your clinic reporting issues with school, and, recently at work too. They have a history of ADHD and were treated for it in high
school. However, they felt “like a zombie” all the time and didn’t want to be on medication. Now, they are struggling to maintain their grades and making
mistakes at their job. What would you suggest?
For this patient scenario first I would want to find out what medication it was they were taking that made them feel that way. If they had been on a stimulant
prior I would recommend using one of the two norandrenegic medications atomoxetine or bupropion. These medications are often used for patient who
experienced side effects from stimulants (Stahl, 2021). If the medication they had been on before was an norandrenergic medication, because according to
Cerrillo-Urbina et al. (2018) these can cause the side effect of somnolence I would recommend attempting methylphenidate since this has a lower abuse
potential (Stahl, 2021).
References
Cerrillo-Urbina, A., García-Hermoso, A., Pardo-Guijarro, M., Sánchez-López, M., Santos-Gómez, J., & Martínez-Vizcaíno, V. (2018).The effects of long-acting
stimulant and nonstimulant medications in children and adolescents with attention-deficit/hyperactivity disorder: A meta-analysis of randomized controlled
trials. Journal of Child and Adolescent Psychopharmacology, 28(8), 494-507. http://doi.org.proxy.libraries.uc.edu/10.1089/cap.2017.0151 (Links to an
external site.)
Stahl, S. M. (2021). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (5th ed.). Cambridge University Press.
Laletha
2. Explain the mechanism of action of lisdexamfetamine. Why is this agent more difficult to abuse?
Drugs that have a high potential for abuse interact with the dopamine transporter (DAT) for too long, too fast, and too much. Lisdexamfetamine is the
prodrug of the D-isomer of amphetamine bound to lysine. Lysine is cleaved slowly in the stomach and converted into active D-amphetamine, which causes
slow absorption into the bloodstream. This optimizes the length of time, rate, and amount of DAT inhibition for therapeutic use but below what is typically
known for abuse potential (Stahl, 2021).
As we have learned in previous modules, many medications are used “off label.” Which medications are used “off label” to treat ADHD or to augment first line
treatment?
There are several medications used off-label for the treatment of ADHD. Below are a few drugs that are not indicated for ADHD but have shown various
degrees of effectiveness. The NDRI, bupropion indicated for depression, has been shown to decrease symptoms of ADHD (Verbeeck et al., 2017). Alpha-2-
adrenergic agonists used for hypertension, immediate-release clonidine (Catapres), and immediate-release guanfacine (Tenex) are prescribed. The extendedrelease versions of these drugs are FDA approved for ADHD; however, the immediate release drugs are prescribed off-label (Panther et al.,2017). Modafinil is
indicated for sleep disorders but is helpful for ADHD because it enhances cognitive performance (Wang et al., 2016). SNRIs venlafaxine and dasotraline are
used off-label for ADHD and are effective because they increase norepinephrine and serotonin, leading to improved concentration. NMDA receptor
antagonists, amantadine and memantine, are helpful for ADHD because they stimulate dopamine production. Amantadine is indicated to treat Parkinson’s
disease, and memantine is used for dementia (Pozzi et al., 2020).
Read the following scenario. There is no “right answer.” Please support your answer with evidence.