Not all meds need blood levels to regulate dosage
DEAR DR. ROACH: My son was diagnosed with obsessive compulsive disorder. The doctor prescribed sertraline (Zoloft). When I inquired about a blood test to determine his serotonin levels, the doctor told me it wasn’t necessary. How could a medication be prescribed without knowing what his levels are? My wife has her levels checked each year for her thyroid medication. -- M.M.
ANSWER: There are some medications whose effectiveness can be followed using blood tests, and a few that must be. If a medication is being used to treat a symptom, it usually is more important to treat the symptom than to treat a number, so sometimes experienced clinicians will use a dose that causes the blood level to be a bit higher or lower than recommended. On the other hand, some medicines -- for instance, warfarin to prevent blood clotting -- need to be precisely regulated using blood testing to be sure it is both effective and nontoxic.
In the case of sertraline and other selective serotonin reuptake inhibitors, there isn’t a blood test to be followed. It’s not serotonin in the blood that is affected by these medications, but serotonin in the synapses (the connections between brain cells). SSRIs block the clearing of serotonin after it is released, allowing the nerve to increase the rate of firing.
The dose of sertraline depends on the condition treated. Smaller doses are needed for anxiety or depression than usually are needed for obsessive compulsive disorder. Fortunately, sertraline is fairly safe: Even the higher doses needed for OCD generally have few side effects.
DEAR DR. ROACH: Your recent column on shortness of breath hit home. At age 59, I had shortness of breath, and my doctors said I had asthma. That winter I got pneumonia, and a sharp doctor saw something on my test results and called in a cardiologist. After talking with and examining me and reviewing my scans, he called it cardiac amyloidosis. Further tests proved him right. I have the wild type. Unfortunately, there is no cure. They are finding this disease in younger people today, and often it is missed or misdiagnosed. -- J.P.
ANSWER: I am sorry to hear about your diagnosis. I have seen a few cases of cardiac amyloidosis. Amyloid is a family of related proteins, and amyloidosis is the deposition of a type of that protein into various organs. The deposited protein interferes with the functioning of the organ. The kidneys, skin, liver, muscles and nerves all may be affected.
Amyloidosis can occur in combination with various diseases, especially multiple myeloma. Myeloma -- a disease of plasma cells, which make antibodies -- is associated with AL amyloidosis. These proteins are made up of the light chain of antibodies, and this is the type that also occurs in people with no underlying disorder. (This used to be called “primary amyloidosis”).
There is another type, called ATTR amyloidosis. A mutation of this gene causes familial amyloidosis, but the “wild type,” a non-mutated gene, causes many cases of what used to be called “senile systemic amyloidosis” (“senile” because it happens in older adults).
In cardiac amyloidosis, the proteins interfere with the function of the heart, which can lead to the heart being unable to pump efficiently and the clinical syndrome of heart failure. It also can affect the conduction system.
Treatment for cardiac amyloidosis needs to be undertaken by an expert, as therapies for other types of heart failure can be ineffective or even harmful in people with cardiac amyloidosis. Heart transplant sometimes is considered for very severe cases.
You are right that this disease is underdiagnosed, and I appreciate your writing to help raise awareness. More information is available at www. amyloidosis.org.
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 request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com. (c) 2017 North America Syndicate Inc. All Rights Reserved