In the U.S.—

In Canada—

• Tocolytic

Ritodrine ( RI-toe-dreen) is used to stop premature labor. It is available only with your doctor's prescription and is to be administered only by or under the supervision of your doctor.

Ritodrine is available in the following dosage forms:

Oral
• Extended-release capsules (Canada)
• Tablets (Canada)

Parenteral
• Injection (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For ritodrine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to ritodrine or sulfites. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking or receiving ritodrine, it is especially important that your health care professional know if you are taking any of the following:

• Beta-adrenergic blocking agents (acebutolol [e.g., Sectral], atenolol [e.g., Tenormin], betaxolol [e.g., Kerlone], bisoprolol [e.g., Zebeta], carteolol [e.g., Cartrol], labetalol [e.g., Normodyne], metoprolol [e.g., Lopressor], nadolol [e.g., Corgard], oxprenolol [e.g., Trasicor], penbutolol [e.g., Levatol], pindolol [e.g., Visken], propranolol [e.g., Inderal], sotalol [e.g., Sotacor], timolol [e.g., Blocadren])—Ritodrine may be less effective if it is used with any of these medicines

• Corticosteroids (cortisone-like medicines)—These medicines are often given together to the mother to help her baby's lungs develop. If you are taking corticosteroids, your dose may need to be changed if ritodrine is also taken or injected. Sometimes the combination of these medicines increases the chance of side effects occurring in the mother.

• Medicine for asthma or breathing problems—Because these products have some effects that are similar to those of ritodrine, the chance of side effects developing is increased when these medicines are used with ritodrine

• Diabetes mellitus (sugar diabetes)—Ritodrine may make this condition worse

• Heart or blood vessel disease or
• Overactive thyroid, uncontrolled—Use of ritodrine may cause serious effects of the heart, including irregular heartbeat

• High blood pressure (hypertension), uncontrolled, or
• Migraine headaches (or history of)—Ritodrine may make these conditions worse. Rarely, use of ritodrine during a migraine headache may cause problems with blood circulation in the brain

Dosing—

The dose of ritodrine will be different for different women. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of ritodrine. If your dose is different, do not change it unless your doctor tells you to do so. The injection form of this medicine will be given to you by your health care professional.

• For oral dosage form (extended-release capsules):
  • Adults: In the first twenty-four hours after the doctor stops your intravenous ritodrine, your dose may be as high as 40 milligrams (mg) every eight hours. After that, the dose is usually 40 mg taken every eight to twelve hours. Your doctor may want you to take oral ritodrine up until it is time for you to deliver your baby or until your 37th week of pregnancy.
• For oral dosage form (tablets):
  • Adults: In the first twenty-four hours after the doctor stops your intravenous ritodrine, your dose may be as high as 10 mg every two hours. After that, the dose is usually 10 to 20 mg every four to six hours. Your doctor may want you to take oral ritodrine up until it is time for you to deliver your baby or until your 37th week of pregnancy.
• For injection dosage form:
  • Adults: 50 to 350 micrograms per minute, injected into a vein.

Missed dose—

If you miss an oral dose of this medicine and remember within an hour or so of the missed dose, take it right away. However, if you do not remember until later, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Check with your doctor right away if your contractions begin again or your water breaks.

Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems since they may increase the unwanted effects of this medicine.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Tell your health care professional immediately if either of the following side effects occurs while you are receiving this medicine:

• More common
  • Chest pain or tightness;  shortness of breath—rare with oral form 
  
  

Check with your health care professional as soon as possible if the following side effects occur:

• More common
  • Blurred vision;  dizziness or lightheadedness ;  drowsiness;  dry mouth ;  flushed and dry skin;  fast or irregular heartbeat—rare with oral form;  fruit-like breath odor;  increased urination;  loss of appetite;  nausea;  severe pounding or racing heartbeat—rare with oral form ;  sleepiness;  stomachache ;  tiredness;  troubled breathing (rapid and deep);  unusual thirst;  vomiting 
  
  

• Rare
  • Sore throat or fever;  yellow eyes or skin 
  
  

• Symptoms of overdose
  • Fast or irregular heartbeat (severe);  nausea or vomiting (severe);  nervousness or trembling (severe);  shortness of breath (severe) 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Headache;  reddened skin;  trembling 
  
  

• Less common or rare
  • Anxiety;  emotional upset;  jitteriness, nervousness, or restlessness;  skin rash 
  
  

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this period of time check with your doctor if you notice the following side effect:

• Shortness of breath 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.