Recently there has been a shortage of the ADHD drug Adderall, manufactured by Shire PLC. As a result there has been finger-pointing between Shire and the US-Drug Enforcement Agency (DEA) as to the root cause. Shire blames the shortage on DEA limits governing the amounts of Drug Product that can be manufactured. The DEA defends their limits saying they are adequate to allow an uninterrupted supply. In the middle of this Senator Amy Klobuchar (D., MN) sent a letter to Shire saying that this shortage is forcing ADHD medication users to switch to more expensive branded drugs to compensate for the shortage.
Adderall, and most ADHD medications are Schedule II or III drugs. There are five levels of DEA controlled substances, C-I through C-V. Each classified by the chemical’s potential for abuse. All Scheduled drugs are subject to “quotas”, the total amount of drug allowed by the DEA in the US for manufacture into Drug Product. Each year the DEA publishes a quota defining how much of each drug is allowed in the US. Each drug manufacturer must petition the DEA for a share of the quota based on projected yearly requirements. Throughout the course of the year, manufacturers can request an additional quota. Shire requested additional quota in 2010 but did not receive it until December; a contributing factor for sporadic availability. The 2010 amphetamine quota for sale was 18,600,000 grams split between all drug manufacturers.
I have formulated several Drug Products incorporating C-III drugs. The DEA has very rigorous procedures for monitoring over 350 controlled substances. The paperwork and in-house controls for protecting these drugs from abuse (theft) is substantial. A Drug Manufacturer must accurately estimate how much API is required for Drug Product for commercial sale; while the DEA must balance how much of a controlled substance to allow into the country. This is a very difficult balance to achieve.
The DEA must maintain tight control over drug levels, while the individual drug manufacturers endeavor to maximize sales. I believe that the blame for these medication shortages probably lies more with the drug manufacturer, as the DEA states that their quota quantities are based estimates of the amount of drug needed to allow an uninterrupted supply. However, in support of the drug manufacturer’s estimates, if anything goes wrong with the manufacturing process (failed batch release, API release failure), the needs estimates can become wrong very fast.
For additional information on ADHD in the US, please click the CDC ADHD Data and Statistics.