XENAZINE SIDE EFFECTS
- Generic Name: tetrabenazine tablets
- Brand Name: Xenazine
- Drug Class: VMAT2 Inhibitors
SIDE EFFECTS
The following serious adverse reactions are described below and elsewhere in the labeling:
- Depression and suicidality
- Akathisia, restlessness, and agitation
- Parkinsonism
- Dysphagia
- Sedation and somnolence
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
During its development, XENAZINE was administered to 773 unique subjects and patients. The conditions and duration of exposure to XENAZINE varied greatly, and included single and multiple dose clinical pharmacology studies in healthy volunteers (n=259) and open-label (n=529) and double-blind studies (n=84) in patients.
In a randomized, 12-week, placebo-controlled clinical trial of HD patients, adverse reactions were more common in the XENAZINE group than in the placebo group. Forty-nine of 54 (91%) patients who received XENAZINE experienced one or more adverse reactions at any time during the study. The most common adverse reactions were (over 10%, and at least 5% greater than placebo) were sedation/somnolence, fatigue, insomnia, depression, akathisia, and nausea.
Adverse Reactions Occurring in ≥ 4% Patients
The number and percentage of the most common adverse reactions that occurred at any time during the study in ≥ 4% of XENAZINE-treated patients, and with a greater frequency than in placebo-treated patients, are presented in Table 1.
Table 1: Adverse Reactions in a 12-Week, Double-Blind, Placebo-Controlled Trial in Patients with Huntington’s Disease
| Adverse Reactionm | XENAZINE n = 54 % |
Placebo n = 30 % |
| Sedation/somnolence | 31 | 3 |
| Insomnia | 22 | 0 |
| Depression | 19 | 0 |
| Anxiety/anxiety aggravated | 15 | 3 |
| Irritability | 9 | 3 |
| Decreased appetite | 4 | 0 |
| Obsessive reaction | 4 | 0 |
| Akathisia | 19 | 0 |
| Balance difficulty | 9 | 0 |
| Parkinsonism/bradykine sia | 9 | 0 |
| Dizziness | 4 | 0 |
| Dysarthria | 4 | 0 |
| Unsteady gait | 4 | 0 |
| Headache | 4 | 3 |
| Nausea | 13 | 7 |
| Vomiting | 6 | 3 |
| Fatigue | 22 | 13 |
| Fall | 15 | 13 |
| Laceration (head) | 6 | 0 |
| Ecchymosis | 6 | 0 |
| Upper respiratory tract infection | 11 | 7 |
| Shortness of breath | 4 | 0 |
| Bronchitis | 4 | 0 |
| Dysuria | 4 | 0 |
Dose escalation was discontinued or dosage of study drug was reduced because of one or more adverse reactions in 28 of 54 (52%) patients randomized to XENAZINE. These adverse reactions consisted of sedation (15), akathisia (7), parkinsonism (4), depression (3), anxiety (2), fatigue (1) and diarrhea (1). Some patients had more than one AR and are, therefore, counted more than once.
Adverse Reactions Due to Extrapyramidal Symptoms
Table 2 describes the incidence of events considered to be extrapyramidal adverse reactions which occurred at a greater frequency in XENAZINE-treated patients compared to placebo-treated patients.
Table 2: Adverse Reactions Due to Extrapyramidal Symptoms in a 12-Week, Double-Blind, Placebo-Controlled Trial in Patients with Huntington’s disease
| XENAZINE n = 54% |
Placebo n = 30% |
|
| Akathisia 1 | 19% | 0 |
| Extrapyramidal event 2 | 15% | 0 |
| Any extrapyramidal event | 33% | 0 |
| 1Patients with the following adverse event preferred terms were counted in this category: akathisia, hyperkinesia, restlessness. 2Patients with the following adverse event preferred terms were counted in this category: bradykinesia, parkinsonism, extrapyramidal disorder, hypertonia. |
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Patients may have had events in more than one category.
Postmarketing Experience
The following adverse reactions have been identified during post-approval use of XENAZINE. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Nervous system disorders: tremor
Psychiatric disorders: confusion, worsening aggression
Respiratory, thoracic and mediastinal disorders: pneumonia
Skin and subcutaneous tissue disorders: hyperhidrosis, skin rash
SRC: NLM .