Methyldopate

• It is used to treat high blood pressure.

• If you have an allergy to methyldopa or any other part of methyldopate.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have liver disease or if this medicine caused liver problems before.
• If you have taken certain drugs used for low mood (depression) like isocarboxazid, phenelzine, or tranylcypromine or drugs used for Parkinson's disease like selegiline or rasagiline in the last 14 days. Taking methyldopate within 14 days of those drugs can cause very bad high blood pressure.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take methyldopate with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about methyldopate, please talk with your doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about methyldopate. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using methyldopate.

Review Date: October 4, 2017

Methyldopate HCl Injection, USP, is an antihypertensive agent for intravenous use. Sterile, nonpyrogenic.

Methyldopate hydrochloride [levo-3-(3,4-dihydroxyphenyl)-2-methylalanine, ethyl ester hydrochloride] is the ethyl ester of methyldopa, supplied as the hydrochloride salt with a molecular weight of 275.73. Methyldopate hydrochloride is more soluble and stable in solution than methyldopa and is the preferred form for intravenous use.

The molecular formula for Methyldopate hydrochloride is C12H17NO4·HCl and the structural formula is:

Each mL contains:

Methyldopate Hydrochloride ......... 50 mg
Citric Acid (Anhydrous) ................. 5 mg
Edetate Disodium ......................... 0.5 mg
Monothioglycerol ...........................  2 mg
Water for Injection ................q.s. to 1 mL

Methylparaben 1.5 mg and Propylparaben 0.2 mg added as preservatives, Sodium Bisulfite 3.2 mg added as an antioxidant. pH adjusted with Sodium Hydroxide and/or Hydrochloric Acid.

General

Methyldopa should be used with caution in patients with a history of previous liver disease or dysfunction (see “WARNINGS”).

Some patients taking methyldopa experience clinical edema or weight gain which may be controlled by use of a diuretic. Methyldopa should not be continued if edema progresses or signs of heart failure appear.

A paradoxical pressor response has been reported with intravenous administration of Methyldopate HCl Injection.

Hypertension has recurred occasionally after dialysis in patients given methyldopa because the drug is removed by this procedure.

Rarely involuntary choreoathetotic movements have been observed during therapy with methyldopa in patients with severe bilateral cerebrovascular disease. Should these movements occur, stop therapy.

Laboratory Tests

Blood count, Coombs test, and liver function tests are recommended before initiating therapy and at periodic intervals (see “WARNINGS”).

Drug Interactions

When methyldopa is used with other antihypertensive drugs, potentiation of antihypertensive effect may occur. Patients should be followed carefully to detect side reactions or unusual manifestations of drug idiosyncrasy.

Patients may require reduced doses of anesthetics when on methyldopa. If hypotension does occur during anesthesia, it usually can be controlled by vasopressors. The adrenergic receptors remain sensitive during treatment with methyldopa.

When methyldopa and lithium are given concomitantly the patient should be carefully monitored for symptoms of lithium toxicity. Read the circular for lithium preparations.

Monoamine oxidase (MAO) inhibitors: See CONTRAINDICATIONS.

Drug/Laboratory Test Interactions

Methyldopa may interfere with measurement of: urinary uric acid by the phosphotungstate method, serum creatinine by the alkaline picrate method, and SGOT by colorimetric methods. Interference with spectrophotometric methods for SGOT analysis has not been reported.

Since methyldopa causes fluorescence in urine samples at the same wavelengths as catecholamines, falsely high levels of urinary catecholamines may be reported. This will interfere with the diagnosis of pheochromocytoma. It is important to recognize this phenomenon before a patient with a possible pheochromocytoma is subjected to surgery. Methyldopa does not interfere with measurement of VMA (vanillylmandelic acid), a test for pheochromocytoma, by those methods which convert VMA to vanillin. Methyldopa is not recommended for the treatment of patients with pheochromocytoma. Rarely, when urine is exposed to air after voiding, it may darken because of breakdown of methyldopa or its metabolites.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No evidence of a tumorigenic effect was seen when methyldopa was given for two years to mice at doses up to 1800 mg/kg/day or to rats at doses up to 240 mg/kg/day (30 and 4 times the maximum recommended human dose in mice and rats, respectively, when compared on the basis of body weight; 2.5 and 0.6 times the maximum recommended human dose in mice and rats, respectively, when compared on the basis of body surface area; calculations assume a patient weight of 50 kg).

Methyldopa was not mutagenic in the Ames Test and did not increase chromosomal aberration or sister chromatic exchanges in Chinese hamster ovary cells. These in vitro studies were carried out both with and without exogenous metabolic activation.

Fertility was unaffected when methyldopa was given to male and female rats at 100 mg/kg/day (1.7 times the maximum daily human dose when compared on the basis of body weight; 0.2 times the maximum daily human dose when compared on the basis of body surface area). Methyldopa decreased sperm count, sperm motility, the number of late spermatids and the male fertility index when given to male rats at 200 and 400 mg/kg/day (3.3 and 6.7 times the maximum daily human dose when compared on the basis of body weight; 0.5 and 1 times the maximum daily human dose when compared on the basis of body surface area).

Long-term studies in animals have not been performed to evaluate the carcinogenic potential of Methyldopate hydrochloride; nor have evaluations of this ester's mutagenic potential or potential to affect fertility been carried out.

Pregnancy

Pregnancy Category C. Animal reproduction studies have not been conducted with Methyldopate HCl. It is also not known whether Methyldopate HCl can affect reproduction capacity or can cause fetal harm when given to a pregnant woman. Methyldopate HCl should be given to a pregnant woman only if clearly needed.

Nursing Mothers

Methyldopa appears in breast milk. Therefore, caution should be exercised when methyldopa is given to a nursing woman.

Pediatric Use

There are no well-controlled clinical trials in pediatric patients. Information on dosing in pediatric patients is supported by evidence from published literature regarding the treatment of hypertension in pediatric patients. (See DOSAGE AND ADMINISTRATION.)

Methyldopate HCl Injection when given intravenously in effective doses, causes a decline in blood pressure that may begin in four to six hours and last 10 to 16 hours after injection.

Add the desired dose of Methyldopate HCl Injection to 100 mL of Dextrose Injection 5%, USP. Alternatively the desired dose may be given in 5% dextrose in water in a concentration of 100 mg/10 mL. Give this intravenous infusion slowly over a period of 30 to 60 minutes.

Adults: The usual adult dosage intravenously is 250 mg to 500 mg at six hour intervals as required. The maximum recommended intravenous dose is 1 gram every six hours.

When control has been obtained, oral therapy with tablets may be substituted for intravenous therapy, starting with the same dosage schedule used for the parenteral route. The effectiveness and anticipated responses are described in the circular for tablets.

Since Methyldopate has a relatively short duration of action, withdrawal is followed by return of hypertension usually within 48 hours. This is not complicated by an overshoot of blood pressure.

Occasionally tolerance may occur, usually between the second and third month of therapy. Adding a diuretic or increasing the dosage of methyldopa frequently will restore effective control of blood pressure. A thiazide may be added at any time during methyldopa therapy and is recommended if therapy has not been started with a thiazide or if effective control of blood pressure cannot be maintained on 2 grams of methyldopa daily.

Methyldopa is largely excreted by the kidney and patients with impaired renal function may respond to smaller doses. Syncope in older patients may be related to an increased sensitivity and advanced arteriosclerotic vascular disease. This may be avoided by lower doses.

Pediatric Patients: The recommended daily dosage is 20 to 40 mg/kg of body weight in divided doses every six hours. The maximum dosage is 65 mg/kg or 3 grams daily, whichever is less. When the blood pressure is under control, continue with oral therapy using tablets in the same dosage as for the parenteral route. (see PRECAUTIONS, Pediatric Use.)

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Methyldopate HCl Injection, USP 250 mg/5 mL (50 mg/mL).

NDC 0517-8905-10   5 mL Single Dose Vial   Boxes of 10

Store at 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F) (See USP Controlled Room Temperature).

Rx Only

IN8905
Rev. 11/05
MG #7604

AMERICAN
REGENT, INC.
SHIRLEY, NY  11967

PRINCIPAL DISPLAY PANEL – Carton

Methyldopate HCl
INJECTION, USP

250 mg/5 mL (50 mg/mL)

NDC 0517-8905-10

10 x 5 mL
SINGLE DOSE VIALS

FOR INTRAVENOUS USE AFTER DILUTION

Rx Only

Each mL contains: Methyldopate HCl 50 mg, Citric Acid (Anhydrous) 5 mg, Edetate Disodium 0.5 mg, Monothioglycerol 2 mg, Water for Injection q.s. Methylparaben 1.5 mg and Propylparaben 0.2 mg added as preservatives, Sodium Bisulfite 3.2 mg added as an antioxidant. pH adjusted with Sodium Hydroxide and/or Hydrochloric Acid.
DISCARD UNUSED PORTION.
Store at 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F) (See USP Controlled Room Temperature).
Directions for Use: See Package Insert.

AMERICAN
REGENT, INC.
SHIRLEY, NY 11967

Rev. 11/05