Hi, He should have his blood pressure monitored and look for any difference between sitting blood pressure and standing blood pressures as postural drop can be a cause of his dizziness. Propfol can can cause lowering of blood pressure but the effect doesn t usually last this long. Also, serum electrolytes may be needed to look for any low sodium or potassium as before colonoscopy laxatives given to induce diarrhea to empty the gut may cause loss of electrolytes too. Probiotics may also help along with good hydration and oral rehydration salts intake. Hope I have answered your query. Let me know if I can assist you further. Wishing you a speedy recovery. Regards, Dr. Saddiq Ulabidin, General & Family Physician