This study will determine if nifedipine, a medication used to treat high blood pressure, can
help treat iron overload, a condition in which the body contains too much iron. Iron overload
can be caused by the body's inability to regulate iron or by medical treatments, such as
multiple blood transfusions. Over time, it can cause problems with the liver, heart and
glands. Treatments include reducing iron intake in the diet or removing the excess iron using
medical therapies. Recently, nifedipine was found to cause iron loss in the urine of small
animals. This study will see if the drug can increase the removal of iron into the urine in
humans as well.
People 18 years of age and older with iron overload may be eligible for this study to undergo
the following procedures:
Study Day 1
Participants come to the NIH Clinical Center for a medical history, physical examination,
blood and urine tests, electrocardiogram (EKG) and echocardiogram (heart ultrasound).
Study Day 2
Participants will collect three urine samples: one is collected over 4 hours, followed by a
second over 4 hours. Both of these samples are collected at NIH in the outpatient day
hospital. At home, a third urine sample will be collected over 16 hours. For 1 week before
the collections, participants are asked not to drink tea or eat foods high in Vitamin C or
iron. They are also asked not to take any iron chelating medications.
Study Day 3
Participants repeat the same urine collections as on day 2. They collect a 4-hour urine
sample at the outpatient day hospital at NIH. They will then take a 20-mg tablet of
nifedipine, and remain in the clinic 4 hours for blood pressure monitoring. A second urine
sample during this time. They then return home to collect the final 16-hour sample, which
they bring to the clinic the following day. Again, they are instructed to avoid a diet high
in vitamin C, iron rich foods, tea, and to avoid taking any iron chelating medications.
...
Phase:
Phase 1
Details
Lead Sponsor:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)