Anti-psychotics: Dibenzothiazepines

Seroquel (generic name: quetiapine)

What’s the deal with Seroquel?

Seroquel is an antipsychotic medication under the classification of the debenzothiazepines. It is used in treatment for patients with symptoms of psychosis, including schizophrenia, post-traumatic stress disorder, and obsessive-compulsive disorder. Psychosis is thought to be due to excesses of dopamine in the brain, or receptors that are oversensitive to dopamine and therefore over stimulated. The manifestations of psychosis including delusional paranoia and hallucinations may be due, then, to too much stimulation or simply too much dopamine.

Just quickly:
Delusions are fixed false beliefs, such as “I am the Queen,” where as hallucinations can be either auditory, visual, tactile, or olfactory (sensory) stimulations that are perceived by the individuals, such as “I have bugs crawling on my skin” (known in medical circles as "formication").

Seroquel works by interfering with the dopamine-2 binding to dopamine-2 receptors. It also antagonizes serotonin, histamine, dopamine-1, and adrenergic alpha-1,2 receptors. The overall result is a decrease in dopamine uptake by the neurons, ultimately resulting in a decrease of psychotic symptoms.

Routes and Dosages
Initially: 25 mg taken twice a day on day one. Increased in 25-50mg intervals twice and day or three times a day on day two and day three. Normal dose is 300-400mg per day in divided doses, two or three times per day; Maximum 800 mg per day, typically in bi-polar type 1 sufferers.

Side Effects
CNS: The big thing with any medication that lowers the amount of dopamine in the central nervous system is extrapyramidal symptoms (EPS). EPS includes akathsia (motor restlessness), dyskinesia (abnormal voluntary movements), dystonia (abnormal muscle tone), and Parkinson’s disease.

“Side Effect” pills, such as anti-Parkinson’s agents like Cogentin and Requip are generally given to counteract the damage done by EPS. Untreated and prolonged use of the antipsychotic medication can result in the permanent tardive dyskinesia.

Not all patients who are taking Seroquel are taking Cogentin or Requip. There are two schools of thought as to why and when to give patients on antipsychotic medications the anti-Parkinsonian drug. Some physicians would prefer to “risk it” because Cogentin itself has side-effects, and the patient is taking an additional medication. In this situation it is important that health care professional be aware of how EPS is manifested and early detection is imperative in avoiding tardive dyskinesia.

The second idea is that it is more likely that the patient will develop EPS, so the anti-Parkinsonian medications are prescribed simultaneously.

Neuroleptic Malignant Syndrome
Pre-disposed factors such as heat stress, physical exhaustion, dehydration, and organic brain disease can contribute to the development of neuroleptic malignant syndrome (NMS). NMS is characterized by hyperpyrexia (fever), muscle rigidity, altered mental status, and autonomic instability; this includes heart palpitations or arrhythmias, abnormal blood pressure, tachycardia (increased heart rate), and diaphoresis (sweating).

Notes on Seroquel: From my experience with this drug, most patients that I have seen are not taking a “side effect” pill concurrently. There is a risk of developing Parkinson’s disease and related malfunctions with decreased dopamine, so you should talk to your doctor regarding the use of a side-effect pill such as Cogentin.