Oseltamivir nausea

Zanamivir was generally well tolerated in clinical trials (Fleming 2003). During treatment with oseltamivir, nausea and vomiting have been reported as side effects (Oxford 2005). A small number of severe adverse reactions in children, including neuropsychiatric events and skin hypersensitivity, have, however, been reported, primarily in Japan which has the highest use of oseltamivir (Li et al. 2007). 

The most frequently reported adverse effects of oseltamivir are nausea and vomiting. These events are usually mild to moderate, occur during the first 1 to 2 days of treatment, and can be lessened by taking the drug with food. Bronchitis, insomnia, and vertigo may also occur. 

Adverse Effects. Oral administration of oseltamivir can cause gastrointestinal disturbances such as nausea, vomiting, diarrhea, and abdominal cramps. Zanamivir, which is administered by inhalation, is associated with bronchospasm and reduced opening of the airway. The adverse effects of zanamivir can be quite severe in people with bronconstrictive disease (asthma, chronic obstructive pulmonary disease), and this drug should probably be avoided in these individuals. 

Oseltamivir is an orally administered prodrug that is activated in the gut and liver. Dosage is 75 mg twice daily. The half-life of oseltamivir is 6-10 hours, and excretion is primarily in the urine. In addition to treatment of influenza, prophylaxis once daily may be effective in preventing influenza. Potential side effects include nausea and vomiting, which may be decreased by administration with food. 

Oseltamivir (GS4104) is an ester prodrug, whose active metabolite (GS4071) is a potent selective inhibitor of influenza virus neuraminidase, to which it is rapidly hydrolysed by hepatic carboxylesterases. The metabolite is then completely excreted by the kidneys by filtration and secretion. In animals oseltamivir had a wide safety margin, with no evidence of teratogenicity or adverse effects on fertility. Oseltamivir has also been studied in the treatment and prevention of influenza A and B, but published results are sparse. To date it has been well tolerated. Headache was the most frequent complaint and mild to moderate gastrointestinal adverse effects (nausea, diarrhea) have been described (3). 

In 730 residents of nursing homes who took oseltamivir prophylaxis for a median of 9 days (range 5-12), adverse effects were identified in 30 (4.1%), of whom 20 had one adverse effect and 10 had two (12). The most common adverse effects were diarrhea (n = 12), nausea or vomiting (n — 7), cough (n = 5), and confusion (n — 4). 

Upper gastrointestinal effects (nausea or nausea with vomiting) have been reported more often in those taking oseltamivir in placebo-controUed studies (16,17). Despite this mild gastrointestinal intolerance, withdrawal rates have been low. 

The oral capsule of oseltamivir can be used in any patient who can swallow. However, it must be given with food, to reduce the frequency of nausea and gastrointestinal discomfort. Of 695 children aged 1-12 years, 14.3% had vomiting compared with 8.5% of those... 

In a meta-analysis of trials, there was a reduction in the duration of symptoms of about 1 day (19). Oseltamivir caused significantly more gastrointestinal symptoms (dyspepsia or nausea) than placebo the effect increased with dose. Similarly, zanamivir caused significantly more gastrointestinal symptoms than placebo (OR = 2.6 95% Cl = 1.6, 4.2). 

Oral oseltamivir is associated with nausea, abdominal discomfort, and, less often, emesis, probably owing to local irritation. GI complaints usually are mild to moderate in intensity, typically resolve in I to 2 days despite continued dosing, and are preventable by administration with food. The frequency of such complaints is about 10 to 15% when oseltamivir is used for the treatment of influenza illness and less than 5% when used for prophylaxis. An increased frequency of headache was reported in one prophylaxis study in elderly adults. 

Fig. 43.5). Two oxidative metabolites also have been isolated, with the major oxidation product being the u)-carboxylic acid (31). Side effects with oseltamivir are minor, consist of nausea and vomiting, and occur primarily in the first two days of therapy. 

Observational studies During a pandemic of HlNl influenza A infection 53 school staff and 273 pupils took oseltamivir for treatment or prophylaxis 41% of pupils and 47% of staff reported adverse reactions and 14% of the pupils and 20% of the staff did not complete the course nausea, vomiting, and rashes were significantly associated with failing to complete the course of treatment [145 ]. 

Drug overdose The pattern of episodes of oseltamivir overdose as reported to Texas poison centers during 2000-2008 has been described [157 ]. Of 298 cases, 92% occurred in December-March (i.e. primarily during outbreaks of influenza), 77% involved patients aged 0-19 years, 73% resulted from therapeutic errors, 90% were managed on-site, and 80% had no effect. The most common adverse reactions were vomiting (7.5%), nausea (3.8%), and abdominal pain (3.8%). 

Systematic reviews In a review of 20 trials (four in prophylaxis, 12 in treatment, and four in postexposure prophylaxis), oseltamivir caused nausea (OR = 1.79 95% Cl = 1.10, 2.93) evidence of rarer adverse events from pharmacovigilance data was of poor quality and such events may in any case have been under-reported psi ]. 

In seven trials involving 7021 participants, nausea and vomiting were more common among those who took oseltamivir (RR = 1.48 Cl = 1.86, 2.33). All the trials... 

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