Most Commonly Prescribed Psychiatric Medications: Desvenlafaxine/Pristiq

Desvenlafaxine is the active metabolite O-desmethylvenlafaxine (ODV) of venlafaxine and is formed as a result of CYP450 2D6. It shares many of the same properties as venlafaxine. 

  • It’s FDA approved for Major depressive disorder 
  • Mechanism of action: This medication will boost the neurotransmitters serotonin, norepinephrine, and dopamine. It does so by blocking the serotonin reuptake pump, the norepinephrine reuptake pump, and increases dopamine in the frontal cortex because dopamine is largely inactivated by the norepinephrine reuptake pump in the frontal cortex. 
  • The dosing is a little easier than venlafaxine. You can start with 50 mg/day with a maximum dose of 100 mg/day. In some cases, doses of 400 mg/day have been shown to be effective but there is increased risk for side effects at higher doses. 
  • Desvenlafaxine is more potent at the serotonin transporter but has greater norepinephrine transporter inhibition relative to venlafaxine. This is one advantage along with lower does required to achieve that inhibition. 
  • These tablets should not be broken, crushed, or chewed, it will alter the controlled release.
  • It has some of the same issues as venlafaxine when it comes to withdrawal or discontinuation. It can be difficult to taper off and may require starting fluoxetine prior to tapering. 
  • Blood pressure must be monitored regularly during treatment.
  • Most common side effects include: nausea (most common 12%), dizziness (8%), increased sweating (6%), constipation (5%).
  • Other side effects: decreased appetite, decreased libido, erectile dysfunction, abnormal dreams, tinnitus, vertigo 
  • I’ve had many questions about combining this with mirtazapine. It can be combined with mirtazapine. Trazodone and bupropion are other popular medications to combine with desvenlafaxine if monotherapy does not result in remission. 
  • Desvenlafaxine offers some benefits over venlafaxine including more consistent plasma levels due to lack of metabolism by CYP 2D6, it has more potent action at the norepinephrine transporter than venlafaxine. It may be a better option if you are targeting the norepinephrine system. 

5 Stage Method for Treatment Resistant Depression (TRD)

I get a lot of questions that go something like this, I’ve been on X, Y, Z medications and nothing seems to help. It seems that what most are asking about is what is the algorithm for treating depression and when does it become treatment resistant. This video will provide a look at what treatment resistant depression is and provides a 5-stage strategy to medication selection.  

Psychotropics: Acamprosate For Alcohol Use Disorder

I received a question asking me to discuss acamprosate as a medication and specifically to address any evidence to support its use to reduce urges to self-harm. I did the research, and this is what I found. 

The Only Medication Proven to Reduce Suicide

As a psychiatry trainee you will never forget that the two medications that reduce suicide are lithium and clozapine. In the case of clozapine, it has been shown in RCTs to reduce suicidal thoughts but not necessarily completed suicides. Lithium on the other hand has RCT data that indicates it reduces suicidal thoughts as well as completed suicide.

Lithium has anti-suicidal effects even at low doses. Lithium’s anti-suicidal effects are beneficial for both unipolar and bipolar depression. Unlike standard antidepressants that can increase the risk of suicide specifically in younger patients under the age 24, lithium has a prophylactic effect to prevent suicide. 

While lithium overdoses can be fatal, this outcome is less likely given the anti-suicidal properties of this medication. We should not avoid prescribing it for this reason. 

Psychiatrists Are More Than Just Prescribers

Introduction:

I get a lot of comments that go something like this “All psychiatrists do is prescribe medications.” Naturally, people are shocked when I talk about nutritional psychiatry, lifestyle modification, or the value of psychotherapy. I cover a lot of medication information on social media because there is significant confusion, misinformation, and a general benefit for patients to know more about the medications they routinely use. 

While medication management is a substantial portion of the work most psychiatrists do it’s not the only things we do. 

Psychotherapy

Most psychiatrists are well trained in at least one type of psychotherapy. The most common ones include cognitive behavioral therapy, interpersonal therapy, and motivational interviewing. Some are trained extensively in psychoanalysis which usually requires a 5-year commitment and engagement in psychoanalysis as a patient.

Procedures

Many psychiatrists offer procedure-based interventions such as electroconvulsive therapy (ECT), and trans cranial magnetic stimulation (TMS). We may also consult on cases of vagus nerve stimulation or deep brain stimulation used to treat severe depression. 

Neurological Disorders

As a psychiatrist you are trained to handle some of the common neurological disorders (e.g. migraine). One third of our board examination is focused on neurological disease. In rural parts of the United States sometimes there is no one else to treat these disorders and the responsibility falls to psychiatry. 

Medical Disorders

Most psychiatrists can treat things like hypertension or hypothyroidism. Many make the choice not to if the patient has a primary care physician. Like the treatment of neurological disorders sometimes there is no choice, and a psychiatrist will need to treat the medical condition. 

Social Work

Not everyone is lucky enough to have designated social workers so they can focus exclusively on the treatment of patients. We all know how important social determinates of mental health are, and sometimes altering these circumstances is the responsibility of the psychiatrist. 

Intramuscular Medication (IM) in Psychiatry: Is it Better?

Intramuscular medication as the name implies is a long-acting injectable form of medication that is usually administered into the gluteal muscle or deltoid muscle and it’s designed to take the place of PO or oral formulations.

The medications available in IM formulations

  • Aripiprazole (Abilify Maintena) 
  • Aripiprazole lauroxil (Aristada) 
  • Fluphenazine (prolixin)
  • Haloperidol (Haldol)
  • Olanzapine pamoate (Zyprexa Relprevv) 
  • Paliperidone (Invega Sustenna, Invega Trinza) 
  • Risperidone (Risperdal Consta) 

Most last between 2-4 weeks but medications like Invega trinza lasts up to 3 months 

This solves one of the major issues when prescribing medication, which is adherence with treatment. 

Notice that all these medications are first- or second-generation dopamine blockers. These medications are commonly used to treat disorder like Bipolar and Schizophrenia (serious mental illness). These populations often have difficulty with medication adherence. 

Clinically most psychiatrists will tell you IM medication improves patient outcomes. However, they may not outperform PO medication taken daily and consistently. Where these medication formulations have the biggest impact is for people who had improvement on oral medication but often forget to take medication or do not want to take medication daily. Many patients with serious mental illness stop taking medication when symptoms resolve making relapse likely. 

Side effects will be similar to the oral medication with the added logistical issue of coming to the office for the injection, and pain at the injection site. Normally we assess tolerability and risk of side effects with oral medication before giving IM medication. This avoids the potential for long lasting side effects. 

Immediate Release Vs Extended-Release Formulations in Psychiatry

Highlights From the Video

Immediate release the medication is released immediately and results is quick onset and a peak blood level. This type of formulation is generally less expensive and may be advantageous in some cases. For example, if you are using quetiapine at night in part for its sedating effects, I will use immediate release because I want a rapid effect. The same with methylphenidate or bupropion. 

The problem is this formulation requires twice a day or even three times per day dosing and results in more peaks and troughs. In general, for medications that are being used for maintenance you want consistent blood levels and not peaks and troughs.

With IR formulations, there can be more side effects and addictive potential. We believe it’s the rapid rise in blood levels of the medication that cause side effects and with medications like amphetamines for ADHD it’s the rapid rise in medication levels that can result in euphoria and thus addictive potential.

Extended release does not change the active ingredient in the medication, rather it provides a different delivery mechanism that slows the release of medication over an extended period of time. This has the opposite effect on blood levels when compared to IR. There will be less peaks and troughs and more sustained blood levels of medication. The advantage is once daily dosing and potentially fewer side effects for the pervious mentioned reasons. 

The downside is these medications tend to cost more money and some have argued when initiating these medications, a patient who has an adverse reaction will have symptoms longer with XR. Although clinically I’m not sure this is true and will generally use extended release if possible for maintenance medications.

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