Naltrexone headache

Naltrexone is hepatotoxic and contraindicated in patients with hepatitis or liver failure. LFTs should be monitored monthly for the first 3 months, then every 3 months. Side effects include nausea, headache, dizziness, nervousness, insomnia, and somnolence. 

The common side effects of naltrexone are nansea, headache, and dizziness. In addition, naltrexone has the potential for toxic effects on the liver and should not be used in an alcoholic with cirrhosis or other known liver disease. Because it blocks opiate receptors, patients treated with naltrexone are unable to benefit from the analgesic effects of opiates such as codeine or morphine. Naltrexone may increase serum levels of acamprosate in patients taking both medications. 

Naltrexone can induce hepatotoxicity at doses only five times the therapeutic dose and should be used with care in patients with poor hepatic function or liver damage. Side effects of the use of naltrexone are more frequently observed than following naloxone administration. Such side effects include headache, difficulty sleeping, lethargy, increased blood pressure, nausea, sneezing, delayed ejaculation, blurred vision, and increased appetite. 

An excellent brief article on buprenorphine treatment has been provided by Taikato et al. (2005), which notes the common possible side-effects (headaches, nausea and vomiting, sweating, constipation, etc.) and drug interactions. The limited central depressant effect of buprenorphine may be compounded by alcohol and antidepressants, while the metabolism of buprenorphine can be enhanced by anticonvulsants, with therefore possibly reduced efficacy. There have been some case reports of liver toxicity from buprenorphine that is reversible if the medication is stopped (Herve et al. 2004), and often clinical guidelines will recommend that liver function tests are included in buprenorphine treatment, as they definitely should be with naltrexone. 

In an open, single-blind, randomized study, naltrexone (50 mg/day) and acamprosate (1665-1998 mg/day) were used for 1 year by 157 recently detoxified alcohol-dependent men with moderate dependence (4). The time to first relapse was 63 days (naltrexone) and 42 days (acamprosate) after 1 year, 41% of those given naltrexone and 17% of those given acamprosate had not relapsed. Adverse effects were more common with naltrexone and were worse during the first 2 weeks of treatment. They included nausea (25 versus 4%), abdominal pain (23 versus 4%), drowsiness (35 versus 2%), headache (13 versus 6%), and nasal congestion (23 versus 7%). 

The Health Technology Board of Scotland has concluded that in people with alcohol dependence, naltrexone reduces drinking (5). In a multicenter, double-blind, placebo-controlled, 12-week study of naltrexone 50 mg/day in 202 patients with alcohol dependence naltrexone was well tolerated, with few adverse effects abdominal pain (8.6%), headache (7.5%), nausea (6.5%), and dizziness (5.4%) there were no changes in liver function tests (6). However, those who took naltrexone did not have significant improvements in drinking history or fewer relapses. 

Nausea is the most common side effect of naltrexone, occurring in about 10% of patients. Other side effects are headache, dizziness, nervousness, fatigue, insomnia, vomiting, anxiety, and somnolence. 

Observational studies The use of naltrexone implants in 23 prison inmates before release from prison reduced the frequency of benzodiazepine and/or heroin use and criminality at 6 months after release but was associated with adverse reactions [18. Pruritus and rash at the implantation site were reported by two patients. Headache, nausea, reduced appetite, sleep disorders, restlessness, and irritability were reported by more than half of the patients. Constipation, diarrhea, and muscle/joint pains were uncommon. There were no serious adverse events. 

Placebo-controlled studies In a doubleblind, randomized, placebo-controlled trial in 80 patients with amfetamine dependence, naltrexone 50 mg/day was given for 12 weeks [207 ]. There were adverse reactions in 14 patients and they were rated as mild. The most frequent reactions were nausea, gastrointestinal discomfort, headache, and fatigue. 

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