H2 RECEPTOR BLOCKERS

Although the H2-receptor blockers are very safe drugs, they are capable of causing thrombocytopenia, a disorder in which there are too few platelets in the blood.

This deficiency may cause bleeding problems, since platelets are essential for blood clotting. Platelet deficiencies can only be recognized by blood tests; there are no symptoms that the patient can see or feel. In addition to affecting platelet levels, the H2-receptor blockers may cause changes in heart rate, making the heart beat either faster or slower than normal. Patients should call a physician immediately if any of these signs occur:
• tingling of the fingers or toes
• difficulty breathing
• difficulty swallowing
• swelling of the face or lips
• rapid heartbeat
• slow heartbeat In addition to these signs, the H2-receptor blockers may cause the following unwanted reactions:
• headache
• diarrhea
• dizziness
• drowsiness
• nausea
• depression
• skin rash
• vomiting

In addition, cimetidine is an inhibitor of male sex hormones; it may cause loss of libido, breast tenderness and enlargement, and impotence. Ranitidine may cause loss of hair or severe skin rashes that require prompt medical attention. In rare cases, this drug may cause a reduction in the white blood cell count.

Before using H2-receptor blockers, people with any of these medical problems should make sure their physicians are aware of their conditions:
• kidney disease
• liver disease
• medical conditions associated with confusion or dizziness