When prescription patents expire, generics not a sure thing

DEAR DR. ROACH: In these days of quickly rising drug costs, some companies lose their patents, allowing for generic versions, but others do not.

I use a brand-name HFA inhaler for my COPD, and it should have gone off patent eight years ago. What change could possibly keep it under patent two times? -- J.C.A.

ANSWER: All patents for drugs expire, but in order for a generic drug to be approved, it must pass stringent testing by the Food and Drug Administration.

One commonly used combination inhaler, Advair, went off patent in 2010, but no generic was approved until 2019. Since brand-name Advair is expensive ($440 per inhaler, which lasts a month, at Goodrx.com), many patients were anxiously awaiting a generic alternative.

It’s finally available (fluticasone/salmeterol) for about $115 an inhaler on GoodRx.

Manufacturers do sometimes change the drug slightly to extend their patents of their best-selling drugs. For many years the Prilosec brand of omeprazole was very expensive.

Just before a generic became available, the manufacturer released a new drug, esomeprazole (Nexium). It is almost exactly the same drug.

DEAR DR. ROACH: Can radiation cause diverticu

litis? -- S.W.

ANSWER: Radiation damage to the colon is common when higher doses of radiation are used, especially in treatment of cancer of the prostate, rectum, anus, cervix, uterus, bladder and testes.

Radiation can damage any cell, but some cell types are more susceptible to radiation damage. Fast-growing cells -- many cancer cells, but also normal cells such as the lining of the intestines -are more readily damaged by radiation.

The blood vessels also may be damaged, leading to further loss of healthy tissue.

Over time, mild and moderate acute damage usually repairs itself, but severe damage can lead to chronic radiation-induced symptoms that last for many years.

The most common symptoms in acute radiation damage are bowel symptoms, like diarrhea, mucus and urgency. People with chronic disease are more likely to have bleeding in addition to the other symptoms.

Diverticula are pouches in the wall of the colon.

These appear in many people, especially as we age, and are more likely in people with a history of constipation or straining.

The condition of having diverticula is called diverticulosis.

These diverticula may become inflamed due to damage of the lining by food particles or by high amounts of pressure in the colon.

Small perforations can result, leading to symptoms of pain, nausea and vomiting, and fever. This is called diverticulitis.

The lining of the diverticula themselves are susceptible to radiation damage, so people with diverticulosis may certainly develop damage to the diverticula along with the rest of the colon, but it isn’t likely since the part of the colon typically exposed to radiation during treatment is usually the end of the colon, the rectum, which is not an area that typically has much diverticulosis.

The sigmoid colon, higher up in the colon, is the most common place for diverticula. But radiation doesn’t cause the diverticula nor typical diverticulitis.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.