Cimetidine

• According to Peteducation.com, side effects of this medication are rare. When they do occur, side effects include a rapid heart beat and difficulty breathing. These effects are more likely to occur in older dogs and dog with blood or kidney diseases.
  
  

Metoclopramide

• Side effects of this drug are sleepiness, nausea, constipation and behavioral changes. Metoclopramide can affect how well the body absorbs other medications.
  
  

Famotidine

• Peteducation.com lists these side effects with famotidine: "vomiting, restlessness, pale gums, rapid heart rate, or collapse." Use caution when administering this drug to a dog with kidney or liver disease.
  
  

Ranitidine

• Ranitidine can interact with other medications, according to Petplace.com. Those drugs include theophylline, propranolol and certain antacids.
  
  

Omeprazole

• According to Petplace.com, side effects of this drug include nausea, diarrhea, vomiting and loose stool.
  
  

Considerations

• Consult your veterinarian before giving any medication to your dog. Make sure to tell your vet what other medications and vitamins you pet is taking at the time.