Dizziness, lightheadedness, drowsiness, headache, stuffy nose, and weakness may occur as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may cause a loss of too much body water (dehydration) and salt/minerals. Tell your doctor right away if you have any symptoms of dehydration or mineral loss, including: extreme thirst, very dry mouth, muscle cramps, weakness, fast/irregular heartbeat, confusion.
Tell your doctor right away if you have any serious side effects, including: fainting, toe/joint pain, change in the amount of urine (not including the normal increase in urine when you first start this drug), swelling ankles/feet, unexplained/sudden weight gain, muscle spasms/uncontrolled muscle movements, missed/stopped periods, decreased sexual desire/ability, increased breast size (in men), mental/mood changes (such as depression), decrease in vision, eye pain.
Methyldopa has rarely caused very serious (rarely fatal) liver disease or low red blood cell count (anemia). Tell your doctor right away if you develop any symptoms of liver disease or anemia, including: unusual tiredness, unexplained fever, dark urine, persistent nausea/vomiting/loss of appetite, severe stomach/abdominal pain, yellowing skin/eyes.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.