II. Indications

III. General

  1. Listed for historical reasons
  2. No longer available in the United States as of 2013
  3. Was the only FDA approved drug for Preterm LaborTocolysis

IV. Efficacy

  1. Not shown to be more effective than Placebo
    1. Does not reduce perinatal mortality or delay labor
    2. (1992) N Engl J Med 327:308-12 [PubMed]

V. Contraindications

  1. Absolute contraindications
    1. Maternal cardiac disease
    2. Pregnancy Induced Hypertension (PIH)
    3. Uncontrolled Diabetes Mellitus
    4. Hyperthyroidism
    5. Hypovolemia
  2. Relative contraindications
    1. Diabetes Mellitus
    2. Chronic Hypertension
    3. Migraine Headache
    4. Resting Tachycardia
    5. Fever

VI. Dosing: Intravenous

  1. Preparation
    1. Mix Ritodrine 150 mg in 500 ml D5W (0.3 mg/ml)
    2. Results in drip of 50 mcg/minute = 10 ml/hour
  2. Start: 50 mcg per minute
  3. Increase by 50 mcg/minute every 10 minutes until
    1. Contractions cease
    2. Adverse effects limit use
    3. Maximum dosage: 350 mcg per minute
  4. After contractions stop
    1. Reduce by 50 mcg every 30 minutes
    2. Titrate dose to lowest effective Tocolytic dose

VII. Dosing: Oral (Not effective)

  1. Start: 10 mg PO every 2 hours for 24 hours
  2. Next: 10 to 20 mg PO every 4 to 6 hours as needed

IX. Monitoring

  1. Baseline testing to consider
    1. Electrocardiogram
    2. Serum Glucose
    3. Serum Potassium
    4. Complete Blood Count
    5. Type and screen
  2. Close monitoring
    1. Blood Pressure for Hypertension
    2. Pulse for maternal Tachycardia over 100
    3. Follow Urine Output
    4. Lung Exam for signs of Pulmonary Edema
    5. Follow Serum Glucose and Serum Potassium
    6. Consider fluid restriction <2400 cc per day

X. References

  1. Gabbe (2002) Obstetrics p. 787-91
  2. Roberts (1998) Procedures Emergency Medicine p. 993-5

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Ontology: Ritodrine (C0035661)

Definition (MSH) An adrenergic beta-2 agonist used to control PREMATURE LABOR.
Definition (NCI) A phenethylamine derivative with tocolytic activity. Ritodrine binds to and activates beta-2 adrenergic receptors of myometrial cells in the uterus, which decreases the intensity and frequency of uterine contractions. Specifically, ritodrine probably activates adenyl cyclase, thereby increasing production of cyclic adenosine monophosphate (cAMP), which in turn enhances the efflux of calcium from vascular smooth muscle cells. A lack of intracellular calcium prevents uterine myometrial contractions. In addition, this agent may directly inactivate myosin light chain kinase, a critical enzyme necessary for the initiation of muscle contractions.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D012312
SnomedCT 372893009, 89785009
English Ritodrine, Benzenemethanol, 4-hydroxy-alpha-(1-((2-(4-hydroxyphenyl)ethyl)amino)ethyl)-, (R*,S*)-, ritodrine, Ritodrine [Chemical/Ingredient], Ritodrine (product), Ritodrine (substance), RITODRINE
Swedish Ritodrin
Czech ritodrin
Finnish Ritodriini
Japanese ウテメック, ウテロトップ, ウルペティック, リトドール, リトメリン, ウテメリン, リメトラーク, ピロスデン, ウテロン, 塩酸リトドリン, フレムーブ, リンドルフ, ウテメナール, ルテオニン, レキサビン, ウテゾールD, リトドリン塩酸塩, リトドリン, プレマル
Polish Rytodryna
Spanish ritodrina (producto), ritodrina (sustancia), ritodrina, Ritodrina
French Ritodrine
German Ritodrin
Italian Ritodrina
Portuguese Ritodrina

Ontology: Yutopar (C0043440)

Definition (CHV) brand name of ritodrine-hydrochloride
Definition (CHV) brand name of ritodrine-hydrochloride
Definition (CHV) brand name of ritodrine-hydrochloride
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D012312
English Pre-Par [brand name], prepar, Yutopar, Pre-Par, Pre Par, Astra Brand of Ritodrine Hydrochloride, Janssen Brand of Ritodrine Hydrochloride, Solvay Brand of Ritodrine Hydrochloride, PrePar