From the FDA Drug Label
The following adverse reactions are based on the 6-week, placebo-controlled studies in which NUPLAZID was administered once daily to patients with hallucinations and delusions associated with PDP Common Adverse Reactions (incidence ≥5% and at least twice the rate of placebo): Adverse reactions that occurred in 6-week, placebo-controlled studies and that were reported at an incidence of ≥2% and >placebo are presented in Table 1 Table 1 Adverse Reactions in Placebo-Controlled Studies of 6-Week Treatment Duration and Reported in ≥2% and >Placebo Percentage of Patients Reporting Adverse Reaction NUPLAZID 34 mg Placebo N=202 N=231 Gastrointestinal disorders Nausea 7% 4% Constipation 4% 3%
Nuplazid (pimavanserin) may cause constipation, with an incidence of 4% compared to 3% with placebo 1.
There is no information about Nuedexta in the provided drug label.
The FDA drug label does not answer the question for Nuedexta.
From the Research
Yes, both Nuedexta (dextromethorphan and quinidine) and Nuplazid (pimavanserin) can cause constipation as a side effect. Nuedexta, which is used to treat pseudobulbar affect, lists constipation as a common side effect occurring in approximately 5-10% of patients 2. Nuplazid, which is prescribed for hallucinations and delusions associated with Parkinson's disease psychosis, has a higher incidence of constipation, affecting about 7-14% of patients in clinical trials. These medications can slow intestinal motility through their effects on various neurotransmitter systems - Nuedexta affects NMDA receptors and sigma-1 receptors, while Nuplazid works on serotonin receptors, particularly 5-HT2A. Some key points to consider:
- The exact mechanism of constipation caused by these medications is not fully understood, but it is thought to be related to their effects on neurotransmitter systems 3.
- Patients taking either medication should stay well-hydrated, maintain physical activity if possible, and consume adequate dietary fiber to help prevent constipation.
- If constipation develops, over-the-counter stool softeners or mild laxatives may be helpful, but patients should consult their healthcare provider before adding any medications, especially if constipation becomes severe or persistent.
- A study published in 2019 found that dextromethorphan-quinidine is often prescribed for patients with dementia and/or Parkinson's disease, despite being approved for pseudobulbar affect 4.
- Another study published in 2014 reviewed the clinical data supporting dextromethorphan combined with quinidine as treatment of pseudobulbar affect, and found that it was generally safe and well tolerated, with no evidence of clinically relevant cardiac or respiratory effects 5.