What Causes Dryness In The Mouth And Dizziness?

my father 91 yoa resumed meds this morning at 9 am after hiatus of 10 weeks. 4 hours later dizzy, very weak, extremely dry mouth and very dry eyes. He took Wellbutrin 150 mg Plavix 75mgT Tamoxifen 20mg Metropolol 25 mgNephrocaps (1) Simvastin 10 mg Tamsulosin ER 0.4 mg Namenda XR 7 mg in that it was 9 am he should not have taken anything else unless he accidentally took Ambien 5 mg or Zolpidem 5 mg