Side Effects of Propylthiouracil & Metoprolol

Propylthiouracil is used to treat hyperthyroidism (overactive thyroid) by preventing the thyroid gland from producing too much thyroid hormone. The thyroid gland regulates heart rate, muscle strength, how well and how fast your body burns calories and many other functions. metoprolol, which is commonly sold under the brand names Lopressor and Toprol XL, is a beta blocker, a drug that relieves stress on the heart. Metoprolol treats high blood pressure, slows a fast heart rate, prevents abnormal heart rhythms, and relieves chest pain.

Functions

• All drugs have side effects, and some of these reactions can be unpleasant. Medications with the same side effects, when used together, can make the side effects stronger. Drugs taken together sometimes also interact with each other; the drugs can work together to treat a condition or enhance healing, or they can work against each other to create other problems.

Side Effects

• Common and infrequent side effects of Propylthiouracil and Metoprolol include nausea, vomiting, dizziness, and fatigue. Additional side effects of propylthiouracil include loss of taste, headache, joint/muscle pain, hair loss, fever, decreased white cell count and burning/tingling of hands/feet. Additional side effects of metoprolol consist of vision problems, weakness, shortness of breath, trouble sleeping, low sex drive, cold hands and depression. If you experience any of these side effects and they persist, report them to your doctor.

Rare Side Effects

• Both drugs can cause rare allergic reactions characterized by rash, itching/swelling (especially of the face/tongue/throat), severe dizziness and trouble breathing. Both propylthiouracil and metoprolol can cause serious, and possibly fatal, liver problems. Symptoms of liver damage include unusual tiredness, abdominal pain, persistent nausea, loss of appetite, yellowing of the skin or eyes, light-colored bowel movements, or dark urine. If you have any of these side effects, seek emergency medical attention immediately.

Warnings

• Propylthiouracil may make metoprolol overly effective. If your thyroid function normalizes and is no longer making too much thyroid hormone, you may have to stop taking propylthiouracil or your dose of metoprolol may have to be reduced. Metoprolol may mask certain symptoms of hyperthyroidism. If you have hyperthyroidism and suddenly stop taking metoprolol, you could experience a thyroid storm, a life-threatening situation characterized by fever as high as 105 to 106°F, rapid heart rate, nausea/vomiting, diarrhea, irregular heart beat, weakness, heart failure and confusion/disorientation.

Considerations

• Tell your doctor if you are pregnant or nursing before taking either of these medications. Even if you are experiencing side effects, don't stop taking either of these medications without seeking medical advice.