Shortage of methazolamide tablets

The American System of Health-System Pharmacists reports a shortage of methazolamide tablets. Neither Fera nor Sandoz provided a reason for this shortage. Since there is no shortage of Fera's brand name version of methazolamide, Neptazane, there will be the usual speculation that the active principle ingredient is being used to produce the more expensive brand name version rather than the less expensive generic versions. If this is untrue, giving a reason for the shortage of the generic versions would be a good way to combat the lie.


Inside the eye, methazolamide inhibits the following reaction, reducing the amount of water produced and thus the pressure that leads to nerve damage and blindness in the case of some types of glaucoma. It has also been used off-label to reduce pressure on the brain by the same mechanism when swelling is occurring due to trauma, etc.

Methazolamide has also been used off-label for some tumors that contain high concentrations of carbon dioxide. In that instance, methazolamide inhibits this reation, leading to tumor cell death.

A more recent off-label use has been inhibition of the carbonic anhydrases involved in the abnormally increased bone resorption in ankylosing spondylitis, a disease that destroys various of the body's joints.

Shortage of Roche Drugs

Roche has a facility in Florence, SC, that manufactures active pharmaceutical ingredients and chemical intermediates for its brand name drugs Tamiflu (oseltamivir), Pegasys (polyethylene glycol reagent), Xeloda (capecitabine), Valcyte (valganciclovir) and Xenical (orlistat). Roche announced in 2010 that it was closing the plant with loss of 300 jobs. South Carolina offered and Roche accepted a $500,000 incentive to keep the plant open, but Roche returned the money in 2011. Since, an internal audit revealed good manufacturing practice problems at the plant. As of January 24th, Roche has advertised for a Manufacturing Quality Assurance Specialist  and a Director of Manufacturing, These are two of eight recently advertised positions for the Florence plant, which might mean that it will remain open for some years.

Readers of this blog are aware of my interest in drug shortages, but none of these current shortages have made ASHP's list, probably because none of the North American and European regulatory agencies have issued a recall. There are indeed many ways to violate GMP standards without impacting the product to the extent that a recall is necessary. These shortages differ in two aspects from those usually noted in this blog and by the American Society of Health-System Pharmacists. First, this is a manufacturing facility for brand name drugs, not generics. Second  these shortages are APIs and the PEG precursor for Pegasys. My recollection is that there is only one generic API shortage, Shortage of labetalol tablets and injectable labetalol. I did receive an inquiry from a distributor of calcium acetate about why they were experiencing increased demand after I posted Shortage of Calcium Acetate Capsules, but there was no shortage of calcium acetate itself.

With all that as background, here are some facts about the individual drugs.

Tamiflu was much in the news in the early 2000s are a means of moderating flu symptoms. Recently a controversy has erupted over its effectiveness. I won't recap this, but you can read the New York Times, Medical News Today, and this Pharmalot blog post.

Pegasys benefits roughly half of the hepatitis C patients to whom it is administered. It is also used to combat hepatitis B. This drug costs $50,000/year/patient, and genetic screening has been proposed to predict which patients will benefit. If you don't want to read the whole thing, you can read the section called INEFFECTIVE DRUGS in this Reuters article about a smaller, faster, and less expensive DNA sequencer.

Xeloda is used alone or in combination with other drugs for cancers of the breast, stomach, colon and rectum. This is one of a group of significantly expensive cancer drugs surveyed by Avalere Health. Their cost has led to prescription abandonment by people who do have health insurance. Here is the abstract of their publication.

Valcyte tablets are prescribed for kidney, pancreas and heart transplant patients with a cytomegalovirus infection activated by the suppression of their immune system required for the transplant. The eyedrops are used by AIDS patients to combat CMV retinitis.

Xenical is prescribed to reduce absorption of fats by people who are obese. It also commonly causes diarrhea, and should only be used under a physician's supervision and with a prescribed reduced-calorie diet.

Shortage of naltrexone tablets

The American Society of Health-System Pharmacists reports a shortage of naltrexone tablets. This drug shortage is likely due to a shortage of the active principal ingredient, naltrexone hydrochloride. Covidien states that this is the reason they have the drug on back order, but Teva and Sandoz did not give a reason. This drug is used to combat alcohol and opioid drug addiction by combining with the receptors in the brain that are occupied by alcohol and opiates.

A question that arises is whether this shortage might be due, at least in part, to FDA approval of 50 mg tablets. Addicts seem to find this amount too high, and ask physicians for prescriptions from compounding pharmacies at a lower dose. Could that be how the active ingredient is being used instead of for the 50 mg tablets? Other addicts take the dubious route detailed on the Internet of obtaining a prescription for the 50 mg tablets, putting a tablet into suspension in distilled water, and gradually increasing their daily intake to combat their withdrawal symptoms.