Methyldopa (Aldomet): What a Nurse Needs to Know
Although the exact hypotensive mechanism is unknown, the current theory is that methyldopa is converted to alpha methylnorepinephrine in centrally located adrenergic neurons. Alpha methylnorepinephrine lowers arterial blood pressure by stimulating the central alpha adrenergic inhibiting receptors.
Drug Interactions
- Methotrimeprazine– An additional side effect of low blood pressure may occur.
- MAO Inhibitors – If administered with Alomet, this combination may cause hallucinations, headache, and high blood pressure.
- Norepinephrine – This drug combined with Aldomet may cause high blood pressure.
Aldomet Dosages
| Dose | Dose | Dose |
|---|---|---|
| Adults | Children | IV Aldomet |
| Give 250mg orally 2 to 3 times daily for 2 days. Dosages should be increased as tolerated. Maintenance: Give 500-2000 mg/day divided into 2-4 dosages. Maximum dosage 3 grams/day. | initially give 10mg/kg body weight in 2-4 divided doses. Increase at 2-day intervals as tolerated up to 65mg/kg or 3 grams/day. | Adults: IV infusion of 250 to 500 mg in D5w given over 30-60 minutes every six hours as needed. The maximum dose is 1 g every 6-12 hours. Children: IV Aldomet 5 to 10 mg/kg body weight in D5W over a 30-60 minute period every 6 hours as needed up to 60mg/kg or 3g/day. |
Nursing Considerations For Aldomet
Assessments
The nurse should use with caution in patients with liver and kidney disorders. The nurse should not use Aldomet in people with liver disease such as cirrhosis.
Risks and benefits should be used in childbearing women.
Interventions
Aldomet causes drowsiness in some patients. Therefore, the nurse should increase the dosage with the evening dose.
Education For the Patient for Aldomet
- Aldomet is a medication that decreases blood pressure. There the nurse must watch the patient for dizziness or falls.
- Aldomet sometimes causes impaired liver and kidney lab values. Before administering Aldomet, the nurse must check the chemistry results.
- Instruct the patient to refrain from prolonged standing as this drug may cause orthostatic low blood pressure.
- Inform the patient they may have drowsiness so avoid driving a vehicle or operating a machine.
Nursing Evaluation
- The nurse should take the patient’s blood pressure and pulse at least two times a shift. Especially when the patient first starts therapy.
- The drug takes an average of 6-8 weeks to become effective. The nurse should assess the patient for tolerance.
- Assess and observe the patient for side effects such as dizziness, lightheadedness, low blood pressure, and decreased output.
- For the first months of therapy, obtain liver and kidney lab enzymes.
- Hemolytic anemia may occur in 4% of patients. This disease can be fatal. A complete blood count should be done throughout the therapy. If this happens, the physician should discontinue the medication and order a Coombs Test.
- While in the hospital, the patient should have intake and output monitored.
Takeaway
Aldomet is a relatively safe drug. In fact, it is often given to pregnant women who have mild high blood pressure. Aldomet does cross the placenta, but it has been administered safely to pregnant women. Aldomet can be safely used while breastfeeding.
Phyllis Robinson MSN, RN is a Registered Nurse of 27 years. Phyllis is passionate about the prevention and healing of heart disease using traditional and alternative methods. She has experience in emergency room, telemetry, infusion, and critical care. Phyllis currently practices in an intensive care unit.
