Why decrease ranitidine absorption with antacids?

Ranitidine absorption can be decreased by antacids because antacids increase the pH level in the stomach, which can affect the solubility and absorption of ranitidine. Ranitidine, being a weak base, may have altered pharmacokinetics when the stomach's acidic environment is neutralized by antacids, leading to reduced bioavailability. Additionally, the timing of administration can also impact the effectiveness, as antacids may physically interfere with the absorption of ranitidine if taken simultaneously. Therefore, it is often recommended to space out the dosing of these medications.