WEDNESDAY, May 11 (HealthDay News) -- Due to an ongoing shortage, some American adults with attention-deficit hyperactivity disorder (ADHD), or the parents of children with ADHD, are having to call multiple pharmacies before finding one that carries the prescription they need to manage the condition.

Accounts of exactly which drugs are affected vary, but much of the focus has been on Adderall XR, made by Shire PLC, and its two generic versions, also made by Shire but distributed by drug companies Teva and Impax.

However, generic versions of the widely used ADHD drugs Ritalin and Concerta have also been affected, Valerie Jensen, associate director of the drug shortages program at the U.S. Food and Drug Administration, told the Wall Street Journal on Tuesday.

Although the shortage doesn't seem severe and, according to industry representatives, should be over by the end of the month, not having the pills can cause significant disruptions to patients' lives.

According to Matt Cabrey, a spokesman for Shire PLC, which makes Adderall XR, the "supply interruption" is due both to higher demand and to the fact that the Drug Enforcement Administration (DEA) didn't deliver enough of the active ingredient in Adderall XR, amphetamine, to the company. Amphetamine is a controlled substance and strictly regulated by the DEA.

For its part, drug maker UCB SA, which makes generic versions of methylphenidate, said its shortages stem from a spike in consumer demand early in 2011. The company hopes to be able to meet consumer demand for its products by May 20, spokeswoman Brenda Varney told the WSJ.

Novartis AG, which also sells generic versions of methylphenidate via its Sandoz unit, told the newspaper that it is also having trouble keeping up with market demand.

As the shortage continues, "Families who are resourceful and able to call around to multiple pharmacies will often find what they need -- but often is not always," said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at the Steven and Alexandra Cohen Children's Medical Center of New York, in New Hyde Park. "In some households, it may not pose a major hardship if they have a short-term disruption in terms of medical treatments, but in some households it can prove a hardship."

One problem: these medicines typically stop working almost as soon as the patient stops using them. Interruption at this particular time -- when the school year is winding down -- could be especially hard for youngsters who rely on their medications to perform academically, Adesman pointed out.

"It could also lead to significant untoward effects behaviorally in the classroom," he said.

According to Adesman, patients (or their parents) should first check with different pharmacies to see if another one has the prescription they need.

"If that doesn't work, have a dialogue with your doctor," said Dr. Lenard A. Adler, director of the Adult ADHD Program at NYU Langone Medical Center in New York City.

There may be reasonable alternatives but they can be a mixed blessing.

Switching drugs isn't always an option. In some cases it can be difficult to translate dosing to another medication, since generics can have subtle differences from brand name drugs.

In the case of Adderall XR, this shouldn't be a problem because the same company manufactures both the brand name and the two generics, noted Shire PLC spokesman Cabrey.

Then there's the financial implications. Switching from a brand-name drug to a generic could save money but going from a generic to a brand name could have the opposite effect on the pocketbook.

There could also be financial repercussions if an insurance company doesn't cover the temporary substitute.

For example, one woman ended up having to pay $140 a month for a new medication, more than twice her previous $60 co-pay, according to the Wall Street Journal.

Some patients may be able to switch from long-lasting pills to short-acting ones but that would mean taking several pills a day instead of just one, Adler said.

Cutting back on doses will have an impact on ADHD symptoms. "They will decrease their improvement if they cut back on their doses," said Adler.

The main thing, said Adler is to "be sure you don't stop your medicine. The impairments of having untreated ADHD are significant."

More information

There's more on ADHD treatments at the U.S. National Institute of Mental Health.