Dopamine antagonists, such as haloperidol and phenothiazines, tend to increase non-REM (rapid eye movement) sleep while reducing REM sleep, according to a 2009 article written by Seiji Nishino, MD at Stanford University. These drugs have been used to mitigate some of the side effects of Parkinsonian medications like levodopa, as anti-psychotics and to treat gastrointestinal problems. Because of the action they have on the central nervous system and muscle movement, they may interfere with sleep and disrupt sleep patterns. Side effects of dopamine antagonists can occur in a range from mild to severe.
Paradoxical Side Effects
Paradoxical side effects may occur from taking dopamine antagonists. While sleep may be interrupted, Drugs.com states that these drugs may also make the patient unusually drowsy.
Feelings of Restlessness
Restless Leg Syndrome and Peripheral Limb Movement Syndrome symptoms have been reported by patients taking dopamine antagonists at the Doctors Lounge Web site in December 2008. However, E. Seigle, MD, responded the side effects were more likely caused by a feeling of restlessness called akathisia.
Rigidity and Hypothermia
In rare cases, a patient taking dopamine antagonists could suffer neuroleptic malignant syndrome which mimics catatonic coma, with muscle rigidity and hypothermia. According to Aaron S. Geller, MD on his Coma Wakening Web site could also suffer extremely disrupted or heightened heartbeat called torsade de pointes ventricular dysrhythmia.
