The benefits and risks of antiviral medication

(CBS) -- Studies show the antiviral flu medication oseltamivir, known by its brand name Tamiflu, can shorten the illness by about a day or two when taken within the first 48 hours of symptoms.

Antiviral treatment is typically recommended for people at high risk for flu complications including children under 2, adults over age 65, pregnant women, and those with chronic health conditions such as asthma, diabetes and heart disease.

As flu cases have surged – so has demand for antivirals. Earlier this month, a Los Angeles CVS temporarily ran out of the drug, and many pharmacies are facing similar spot shortages.

Common Tamiflu side effects include nausea, vomiting, headache and pain. Pediatric infectious disease doctor Amy Edwards says neuropsychiatric side effects usually rare.

"Hallucinations, self-injury behavior that sort of thing. It’s not actually super clear cut whether it’s the Tamiflu that is causing that or influenza itself. Because influenza can cause something called encephalitis, which is inflammation of the brain," she says.

Charlie Harp’s family believes Tamiflu caused the 16-year-old to take his life. They say doctors didn’t properly warn them children may have increased risk of confusion or abnormal behavior.

“They didn't tell you this could possibly be side effects. [They] should let parents know: 'Hey, watch your kids. Don`t leave them alone,” says Harp's relative, Brad Ray.

The makers of Tamiflu say they can't comment on this case. The company says it takes all reports seriously and thoroughly investigates.