Sir,
Naltrexone is an opioid antagonist that has been used for the long-term treatment of opioid dependence and alcohol dependence. As with other medications, this too has its own profile of adverse drug reactions (ADRs). Understanding the nature and pattern of ADRs in a treatment facility can help to inform clinicians in making decisions. The National Drug Dependence Treatment Centre, Ghaziabad has provided an opportunity to closely examine the ADRs related to medications used in the treatment of addictive disorders.[1,2] We sought to analyze the ADRs encountered with naltrexone in a period of about 3 years (August 2016 to December 2019), given the lack of such literature on this topic.[3,4]
This record-based audit was based on 219 ADRs reported by doctors and nurses. The mean age of the sample was 32.38 (±9.67) years. All patients were males. The profile of ADRs encountered is presented in Table 1. While decreased appetite was the most common ADR, other common ones were vomiting and dizziness. ADRs according to system organ classification (MedDRA) suggested gastrointestinal disorders to be the most common (n = 100, 45.7%). According to WHO UMC causality assessment, 157 reports were classified as “possible,” 48 were “probable,” 13 were “certain,” and 1 was “unclassified.” Two hundred and nine (95.4% of the ADRs) were labeled (i.e., mentioned previously in package insert), and they were non-labeled in ten (6.6%). A total of 75 patients were reported as “recovered” (n = 75, 34.3%), and it was “unknown” in 144 (65.7%).
Table 1.
Adverse drug reactions reported (n=219) in patients who used naltrexone
| ADR | Number of reports (%) |
|---|---|
| Decreased appetite | 62 (28.3) |
| Vomiting | 13 (5.9) |
| Dizziness | 11 (5.0) |
| Anxiety | 10 (4.6) |
| Nausea | 10 (4.6) |
| Irritability | 8 (3.7) |
| Restlessness | 7 (3.2) |
| Headache | 6 (2.7) |
| Altered taste | 6 (2.7) |
| Sedation | 5 (2.3) |
| Sleep disturbances | 4 (1.8) |
| Dysphoria, impaired attention, dyspepsia, vertigo, dry mouth, rash, epigastric discomfort, body pains, weight loss | 3 each (1.4 each) |
| Diarrhea, dysgeusia, itching, pruritus, decreased libido, premature ejaculation, skin lesion, sweating, weakness, fatigue | 2 each (0.9 each) |
| Skin eruption, dysphonia, postural hypotension, heaviness of head, swelling of eyelid, nasal stuffiness, nasal discharge, low back ache, general body pain, acne, erythematous rash, popular rash, transient anxiousness, retrosternal burning, popular skin eruption, gastritis, aggressive behavior, depressed mood, back ache, nervousness, head fullness, light-headed feeling, somnolence, lethargy, maculo-popular rash, sensation of cold, abdominal distension, increased lacrimation, pruritic rash | 1 each (0.5 each) |
ADR – Adverse drug reaction
The profile of ADRs suggests that decreased appetite was the most common complaint in patients who receive naltrexone, while previous literature suggested nausea and weakness as the most common ADRs.[3,4] Lack of appetite has implications for trajectory of recovery of patients with alcohol and opioid dependence, both of which are associated with weight loss during the course of active dependence, and weight gain is expected during recovery as patient cease substance use. Furthermore, treating clinicians should focus on gastrointestinal and nervous/psychiatric organ systems in practice when they prescribe naltrexone for the treatment of addictive disorders.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgments
The authors would like to thank the Pharmacovigilance Programme of India.
REFERENCES
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