Histamine H 2-receptor Antagonists (Systemic)

Proper Use of This Medicine

For patients taking the nonprescription strengths of these medicines for heartburn, acid indigestion, and sour stomach:

• Do not take the maximum daily dosage continuously for more than 2 weeks, unless directed to do so by your doctor.
• If you have trouble in swallowing, or persistent abdominal pain, see your doctor promptly. These may be signs of a serious condition that may need different treatment.

For patients taking the prescription strengths of these medicines for more serious problems:

• One dose a day - Take it at bedtime, unless otherwise directed.
• Two doses a day - Take one in the morning and one at bedtime.
• Several doses a day - Take them with meals and at bedtime for best results.

It may take several days before this medicine begins to relieve stomach pain. To help relieve this pain, antacids may be taken with the H ₂ -blocker, unless your doctor has told you not to use them. However, you should wait one-half to one hour between taking the antacid and the H ₂ -blocker.

Take this medicine for the full time of treatment, even if you begin to feel better . Also, it is important that you keep your appointments with your doctor for check-ups so that your doctor will be better able to tell you when to stop taking this medicine.

For patients taking famotidine chewable tablets :

• Chew the tablets well before swallowing.

For patients taking famotidine oral disintegrating tablets :

• Make sure your hands are dry.
• Leave tablets in unopened package until the time of use, then open the pack and remove the tablet.
• Immediately place the tablet on the tongue.
• The tablet will dissolve in seconds, and you may swallow it with your saliva. You do not need to drink water or other liquid to swallow the tablet.

For patients taking ranitidine effervescent granules or tablets :

• Remove the foil wrapping and dissolve the dose in 6 to 8 ounces of water before drinking.

Dosing - The dose of histamine H ₂ -receptor antagonists (also called H ₂ -blockers) will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so .

The number of capsules or tablets or teaspoonfuls of solution, suspension, or syrup that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking the H ₂ -receptor antagonist .

For cimetidine
• For oral dosage forms (solution and tablets):
  • To treat duodenal or gastric ulcers:
    • Older adults, adults, and teenagers - 300 milligrams (mg) four times a day, with meals and at bedtime. Some people may take 400 or 600 mg two times a day, on waking up and at bedtime. Others may take 800 mg at bedtime.
    • Children - 20 to 40 mg per kilogram (kg) (9.1 to 18.2 mg per pound) of body weight a day, divided into four doses, taken with meals and at bedtime.
  • To prevent duodenal ulcers:
    • Older adults, adults, and teenagers - 300 mg two times a day, on waking up and at bedtime. Instead some people may take 400 mg at bedtime.
    • Children - Dose must be determined by your doctor.
  • To treat heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 100 to 200 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 400 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To prevent heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 100 to 200 mg with water up to one hour before eating food or drinking beverages you expect to cause symptoms. Do not take more than 400 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To treat conditions in which the stomach produces too much acid:
    • Adults - 300 mg four times a day, with meals and at bedtime. Your doctor may change the dose if needed.
    • Children - Dose must be determined by your doctor.
  • To treat gastroesophageal reflux disease:
    • Adults - 800 to 1600 mg a day, divided into smaller doses. Treatment usually lasts for 12 weeks.
    • Children - Dose must be determined by your doctor.
• For injectable dosage form:
  • To treat duodenal ulcers, gastric ulcers or conditions in which the stomach produces too much acid:
    • Older adults, adults, and teenagers - 300 mg injected into muscle, every six to eight hours. Or, 300 mg injected slowly into a vein every six to eight hours. Instead, 900 mg may be injected slowly into a vein around the clock at the rate of 37.5 mg per hour. Some people may need 150 mg at first, before beginning the around-the-clock treatment.
    • Children - 5 to 10 mg per kg (2.3 to 4.5 mg per pound) of body weight injected into a vein or muscle, every six to eight hours.
  • To prevent stress-related bleeding:
    • Older adults, adults, and teenagers - 50 mg per hour injected slowly into a vein around the clock for up to 7 days.
    • Children - Dose must be determined by your doctor.

For famotidine
• For oral dosage forms (suspension, tablets, chewable tablets, and oral disintegrating tablets):
  • To treat duodenal ulcers:
    • Older adults, adults, and teenagers - 40 milligrams (mg) once a day at bedtime. Some people may take 20 mg two times day.
    • Children - Dose must be determined by your doctor.
  • To prevent duodenal ulcers:
    • Older adults, adults, and teenagers - 20 mg once a day at bedtime.
    • Children - Dose must be determined by your doctor.
  • To treat gastric ulcers:
    • Older adults, adults, and teenagers - 40 mg once a day at bedtime.
    • Children - Dose must be determined by your doctor.
  • To treat heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 10 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 20 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To prevent heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 10 mg taken one hour before eating a meal you expect to cause symptoms. The dose may be repeated once in twenty-four hours. Do not take more than 20 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To treat conditions in which the stomach produces too much acid:
    • Older adults, adults, and children - 20 mg every six hours. Your doctor may change the dose if needed.
    • Children - Dose must be determined by your doctor.
  • To treat gastroesophageal reflux disease:
    • Older adults, adults, and teenagers - 20 mg two times a day, usually for up to 6 weeks.
    • Children weighing more than 10 kg (22 pounds) - 1 to 2 mg per kilogram (kg) (0.5 to 0.9 mg per pound) of body weight a day divided into two doses.
    • Children weighing less than 10 kg (22 pounds) - 1 to 2 mg per kg (0.5 to 0.9 mg per pound) of body weight a day, divided into three doses.
• For injectable dosage form:
  • To treat duodenal ulcers, gastric ulcers, or conditions in which the stomach produces too much acid:
    • Older adults, adults, and teenagers - 20 mg injected into a vein, every twelve hours.
    • Children - Dose must be determined by your doctor.

For nizatidine
• For oral dosage forms (capsules and tablets):
  • To treat duodenal or gastric ulcers:
    • Older adults, adults, and teenagers - 300 milligrams (mg) once a day at bedtime. Some people may take 150 mg two times a day.
    • Children - Dose must be determined by your doctor.
  • To prevent duodenal ulcers:
    • Adults and teenagers - 150 mg once a day at bedtime.
    • Children - Dose must be determined by your doctor.
  • To prevent heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 75 mg taken thirty to sixty minutes before eating a meal you expect to cause symptoms. The dose may be repeated once in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To treat gastroesophageal reflux disease:
    • Adults and teenagers - 150 mg two times a day.
    • Children - Dose must be determined by your doctor.

For ranitidine
• For oral dosage forms ( effervescent granules, syrup, tablets, effervescent tablets):
  • To treat duodenal ulcers:
    • Older adults, adults, and teenagers - 150 milligrams (mg) two times a day. Some people may take 300 mg once a day at bedtime.
    • Children - 2 to 4 mg per kilogram (kg) (1 to 2 mg per pound) of body weight per day, usually given as two divided doses. .However, your total dose will not be more than 300 mg a day.
  • To prevent duodenal ulcers:
    • Older adults, adults, and teenagers - 150 mg at bedtime.
    • Children - Dose must be determined by your doctor.
  • To treat gastric ulcers:
    • Older adults, adults, and teenagers - 150 mg two times a day.
    • Children - 2 to 4 mg per kilogram (1 to 2 mg per pound) of body weight per day, usually given as two divided doses. However, your total dose will not be more than 300 mg a day.
  • To treat heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 75 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 150 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To prevent heartburn, acid indigestion, and sour stomach:
    • Adults and teenagers - 75 mg with water taken thirty to sixty minutes before eating a meal or drinking beverages you expect to cause symptoms. Do not take more than 150 mg in twenty-four hours.
    • Children - Dose must be determined by your doctor.
  • To treat some conditions in which the stomach produces too much acid:
    • Older adults, adults, and teenagers - 150 mg two times a day. Your doctor may change the dose if needed.
    • Children - Dose must be determined by your doctor.
  • To treat gastroesophageal reflux disease:
    • Older adults, adults, and teenagers - 150 mg two times a day. Your dose may be increased if needed.
    • Children - 5 to 10 mg per kg (2.3 to 4.6 mg per pound) of body weight a day, usually divided and given in two doses during the day. However, most children usually will not take more than 300 mg a day.
• For injectable dosage form:
  • To treat duodenal ulcers, gastric ulcers, or conditions in which the stomach produces too much acid:
    • Older adults, adults, and teenagers - 50 mg injected into a muscle every six to eight hours. Or, 50 mg injected slowly into a vein every six to eight hours. Instead, you may receive 6.25 mg per hour injected slowly into a vein around the clock. However, most people will usually not need more than 400 mg a day.
  • To treat duodenal or gastric ulcers:
    • Children - 2 to 4 mg per kg (1 to 2 mg per pound) of body weight a day, injected slowly into a vein.

Missed dose - If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, 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 the capsule or tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the liquid form of this medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.