The Best Antipsychotic Medication in The World 

Introduction:

I’ve said it before in previous videos, older medications are more effective and newer medications have fewer side effects. 

The advent of SSRIs in the late 1980’s and early 1990’s was largely driven by safety and not efficacy. The same is true for antipsychotic medications. This may be the reason most people haven’t even heard about Clozapine (brand name Clozaril). 

Efficacy

Clozapine is the single most effective antipsychotic available, and it works in treatment resistant schizophrenia where no other medication is proven to be effective. 

The results speak for themselves, 30% of previously treatment resistant patients experience symptom reduction within 6 weeks and that number jumps to 60% after 6 months of treatment. 

Clozapine has a slew of additional benefits including mood stabilizing prosperities (it can be used in bipolar disorder), reduction in psychogenic polydipsia and the hyponatremia associated with it, reduction in hostility and aggression, reduction in the risk of suicidal ideation, improvement in substance use, and it may even help patients quit smoking a difficult task in schizophrenia. 

So why are most schizophrenic patients not on this medication if it’s so great? 

Side effects, side effect, side effects

-Sedation: feeling tired this can largely be mitigated by dosing the medication at night before bedtime. 

-Tachycardia: It’s worth getting an EKG in patients with preexisting heart conditions or those at high risk due to hypertension and hyperlipidemia 

-Sialorrhea: excessive saliva production leading to drooling, no one wants this 

-Dizziness

-Constipation: this should be addressed immediately if a patient complains about it as it can lead to serious complications. In many cases Senna and Colace will do the trick

-Orthostatic hypotension 

-Weight gain 

Serious and potentially fatal Side effects include: 

-Agranulocytosis: decreased absolute neutrophil count which can result in increased risk for serious infection and the reason everyone on the medication gets weekly blood draws for the first 6 months 

-Seizures: clozapine is known to lower the seizure threshold 

-Myocarditis: inflammation of the heart usually due to a viral infection 

The risk for agranulocytosis is highest when starting treatment, usually during the first year of treatment (0.8%) and the maximum risk is between 4 and 18 weeks (when 77% of cases occur), although it can still occur at any point in the treatment.

Agranulocytosis

Monitoring is thus very important, and each patient must be registered in the Risk Evaluation and Mitigation strategy (REMS) data base before starting the medication. 

A CBC with differential must be drawn to calculate the absolute neutrophil count prior to starting treatment and then weekly for the first 6 months. Then monitoring continues every 2 weeks for the next 6 months and finally monthly after the first year of treatment. 

If agranulocytosis occurs stopping clozapine allows majority of cases to recover within 14 days. 

Now that we know that this medication is very effective but comes with a high side effect burden a natural next question might be why does the medication work? 

Mechanism of Action

Clozapine has very low affinity for the D2 receptors which is unique as most other antipsychotics will bind strongly to D2 receptors. Clozapine had far greater D1 and D4 binding affinity, blocking both receptors. 

Clozapine also has significant activity at other neurotransmitter sites. It blocks alpha receptors which may be the reason for orthostatic hypotension. It blocks histamine H1 receptors resulting in sedation and weight gain. It blocks 5-HT2A serotonin receptors and is highly anticholinergic resulting in constipation and urinary retention. 

It has two unique properties; it influences the glutamate system by altering NMDA receptor sensitivity and increases the release of brain derived neurotrophic factor BDNF. 

Metabolism And Drug Interactions

Clozapine is primarily metabolized by CYP450 1A2 and 3A4 and cigarette smoking will cause a reduction in clozapine levels due to induction of CYP 1A2. 

Before Starting the Medication

Before starting clozapine, the ANC must be above 1,500. If neutropenia develops treatment will depend on the severity of the drop. 

Mild Neutropenia: ANC 1,000-1,499, you would continue treatment and check an ANC three times weekly until it reaches 1,500. 

Moderate Neutropenia: ANC between 500 and 999, stop treatment and check the ANC daily until it reaches 1,000 then 3 times weekly until it reaches 1,500 then weekly for 4 weeks before returning to the patients prior monitoring schedule. 

Severe Neutropenia: ANC less than 500, stop treatment and check an ANC daily until it’s 1,000 then 3 times weekly until it’s 1,500. The patient should not be rechallenged without a hematology consult and clear benefits that outweigh the risks. 

Dosing

Clozapine can be started at 12.5 to 25 mg at bedtime. The dose can be increased 25 mg/day inpatient and 25 mg per week in the outpatient setting as tolerated. 

You can overlap prior treatment with another antipsychotic and tapper the old medication once clozapine dose reaches 100 mg or more. 

Plasma Levels

Clozapine dose should be based on serum levels, with a target blood level of 200 to 300 ng/ml. If there are still symptoms present the target serum level is 450 ng/ml. There are no benefits to serum levels above 900 ng/ml. 

 

The Neurobiology of Appetite

Metabolic set point 

People alter the quantity and frequency of food consumption daily and yet the brain seems to have a regulatory process that allows people to maintain a relatively stable body weight. 

Isn’t that crazy? 

Anyone who has ever tried to diet knows all too well about this metabolic set point. There are staggeringly low rates of success with diet programs. A systematic review of studies published between 1931 and 1999 found that only 15% of patients achieved dietary success after 5 years. Most people who diet will slowly return to their preexisting weight within 1 year.

This metabolic set point appears to be controlled by our genetics. There is a strong correlation between the body mass of biological parents and adoptees in adoption-based studies. In the case of weight, genetics has far more influence than environmental factors. 

Despite all this obesity rates in the United States as well as other developed countries continues to rise, so what gives? 

Our genes have difficulty responding to the modern environment. 3000 years ago, when food sources were scarce, it was advantageous to consume and store as many calories as possible. However, in the modern world where there is no shortage of opportunity to consume calorie dense foods, our genetics are working against us. The weight issue is genetic but also influenced by availability of high-calorie delicious food. 

When it comes to weight, energy in (food) must equal energy out (heat and work). The energy out is made up of the resting metabolic rate (calories burned when the body is stationary) and physical activity. The brain has a unique mechanism for managing the RMR. When more calories are consumed the RMR increases and when we diet the RMR is turned down. 

To solidify the point, we can look no further than The Biggest Loser competition. Investigators assessed 14 of the 16 contestants before the competition, after completion of the 30-week program, and 6 years after the show. 13 of the 14 study participants regained weight and 4 were heavier than when they started the competition 6 years ago. The real downer was they all burned less calories at rest 6 years after the show ended. Despite exercising more and theoretically being much healthier their RMR decreased. 

What are the important signals used by the body that indicate when to eat and when to stop eating?

Short-Term signels include: 

Glucose: This is the primary nutrient that mediates satiety. Hypoglycemia will stimulate hunger and increase eating, while glucose infusions will decrease food intake. 

Mechanoreceptors in the gut: The physical presence of food in the stomach activates these receptors due to stretching, the vagus nerve transmits signals of gastric stretch to the hindbrain to decrease eating. 

Gut Hormones: The most well understood is cholecystokinin (CCK) which is released by endocrine cells in the small intestine. This will inhibit further food intake by stimulating the vagus nerve and decreasing gastric emptying. People have tried using CCK as a weight loss measure but all it does is decrease the size of meals but increases the frequency of eating thus producing a net zero effect on weight loss.

Ghrelin is the only gut hormone that stimulates hunger. Some suggest that decreased ghrelin produced by the stomach is the reason gastric bypass surgery is effective for weight loss. 

It’s now known that adipose tissue releases a hormone that conveys information about energy stores. Leptin is produced by fat cells and increases or decreases based on the total amount of fat. Leptin is a hormone that tells the body to stop eating. In the case of obesity leptin levels are high and energy expenditure increases while food intake decreases. When someone goes on a diet and fat stores decrease leptin decreases resulting in decreased energy expenditure and increased food intake. 

Two groups of neurons in the arcuate nucleus of the hypothalamus mediate the leptin signal, proopiomelanocortin (POMC) and neuropeptide Y (NPY). POMC stops eating and NPY increases food intake and decreases energy expenditure. In obesity there is increased leptin which inhibits NPY and activates POMC resulting in increased energy expenditure and decreased food intake. The opposite is true for the lean individual. 

Eating and Pleasure

It’s well established that eating can result in pleasure, we have all had this experience after a stressful week a good meal can instantly change our mindset. The pleasure from food is likely an adaptation that enhanced survival when food sources were scarce. Increased dopamine in the nucleus accumbens and release of endogenous opioids appears to be more active when we are eating a meal we enjoy. 

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