Side Effects of Tamiflu (Oseltamivir) in Pediatric Patients
The most common side effects of Tamiflu in children are gastrointestinal, with vomiting occurring in approximately 16% of treated children compared to 8% receiving placebo, followed by nausea, diarrhea, and headache. 1, 2
Common Adverse Effects by Frequency
Gastrointestinal Effects (Most Common)
- Vomiting is the most frequent adverse reaction, occurring in 16% of pediatric patients aged 1-12 years treated with oseltamivir versus 8% receiving placebo 1, 2
- Nausea occurs in approximately 10% of treated patients 1, 2
- Diarrhea is particularly notable in infants under 1 year of age, occurring in 7% of treated infants 1, 2
- These gastrointestinal symptoms are typically transient, occurring on the first or second treatment day and resolving spontaneously within 1-2 days 2
- Administration with food may improve gastrointestinal tolerability 1
Neurological Effects
Dermatological Effects
Serious but Rare Adverse Effects
Neuropsychiatric Events
- Post-marketing surveillance has reported neuropsychiatric events including abnormal behavior, delirium, hallucinations, agitation, anxiety, altered consciousness, confusion, nightmares, and delusions 3, 2
- However, comprehensive reviews of controlled clinical trial data have failed to establish a causal link between oseltamivir and neurologic or psychiatric events 1, 3
- Influenza infection itself is strongly associated with neuropsychiatric symptoms, which may occur before oseltamivir initiation 3
- The FDA advises monitoring children closely for abnormal behavior during treatment, though the risk in patients taking oseltamivir is no higher than in those not receiving antivirals 3, 2
Hypersensitivity and Skin Reactions
- Serious skin reactions including Stevens-Johnson Syndrome, toxic epidermal necrolysis, and erythema multiforme have been reported post-marketing 2
- Anaphylactic/anaphylactoid reactions, though rare, can occur 1, 2
- Parents should stop oseltamivir immediately if skin rash, hives, blisters, facial swelling, or difficulty breathing develop 2
Age-Specific Considerations
Infants (2 weeks to <1 year)
- The most frequently reported adverse reactions in this age group are vomiting (9%), diarrhea (7%), and diaper rash (7%) 2
- The safety profile is generally comparable to that observed in older pediatric patients 2
Children 1-12 Years
- Vomiting is the predominant adverse effect at 16% versus 8% in placebo 1, 2
- In prophylaxis studies, vomiting occurred in 8% of children receiving oseltamivir versus 2% in the no-prophylaxis group 2
Adolescents (≥13 years)
- The adverse effect profile is similar to adults, with nausea (10%), vomiting (8%), and headache (2%) being most common 1, 2
Special Population Warnings
Hereditary Fructose Intolerance
- One 75 mg dose of oseltamivir oral suspension delivers 2 grams of sorbitol, which exceeds the daily maximum for patients with hereditary fructose intolerance 2
- This may cause dyspepsia and diarrhea in fructose-intolerant patients 2
Critical Clinical Context
Balance of Benefits vs. Harms
- All studies confirmed vomiting as an occasional side effect occurring in approximately 5% of treated patients overall 1
- The balance between benefits and harms should be considered, but current guidelines support that benefits outweigh risks in hospitalized, severely ill, or high-risk pediatric patients 1, 4
- Early oseltamivir treatment in hospitalized children is associated with shorter hospital stays and lower odds of ICU transfer, ECMO use, and death 5