the increase in life expectancy in human beings has lead to the increased prevalence of age - related disorders . elderly patients are prone to systemic impairment and are generally on multidrug therapy , and thus present greater anesthetics challenges . poly - pharmacy in elderly patients is one of the frequent and important factors in the incidences of drug interactions . anesthesiologists need to have in depth understanding of pharmacokinetics and dynamics as well as the possible adverse effect profile of the drugs from the other disciplines . perioperative monitoring must be individualized , considering the reduced safety and functional margins , in this special population and to safeguard the anesthetic outcomes . a 74-year - old woman , weighing 60 kg was posted for modified radical mastectomy under general anesthesia . she was detected to have alzheimer 's disease a year back and diabetes mellitus a month back . the patient was on oral metformin 500 mg bd and glimepride 2 mg od therapy from 1 month and on donepezil 5 mg od oral for 4 months . on examination , the patient apparently displayed slow mentation , fixed facial expression and sluggish motor movements . all routine monitors were attached and intravenous access was secured , following which anesthesia was induced with intravenous administration of morphine 3 mg , propofol 100 mg , and rocuronium 0.6 mg / kg . the patient 's lungs were ventilated for 3 min . on attempting endotracheal intubation , the patient 's spontaneous respiratory efforts reappeared . propofol 20 mg bolus and rocuronium 10 mg were supplemented intravenously to facilitate endotracheal intubation . 15 and 25 min after tracheal intubation , the patient 's spontaneous efforts reappeared and rocuronium was administered intravenously . assuming the possibility of poor efficacy of rocuronium , the muscle relaxant was switched to vecuronium . however , the intraoperative requirement of muscle relaxant continued to remain higher than expected . on completion of the 2 h long surgical procedure and return of spontaneous respiratory efforts , residual neuromuscular blockade was reversed with intravenous administration of neostigmine 60 mcg / kg and glycopyrrolate 10 mcg / kg . after 15 min a supplemental dose of neostigmine 10 mcg / kg and glycopyrrolate 5 mcg / kg were administered but no improvement in the respiratory effort was evident . a rise in heart rate , blood pressure , and blood sugar levels was observed . the patient was put on titrating insulin infusion and was catheterized to monitor the urine output . postoperatively , serial blood gas monitoring showed gradually improving respiratory acidosis with manual ventilatory assistance . as neuromuscular monitoring was not available , clinical parameters of neuromuscular recovery were 	 assessed . as the patient was conscious , following commands , moving her limbs purposefully , and had adequate respiratory efforts , the trachea was extubated . 5 to 10 min after extubation , the patient became tachypenic and was breathing shallow . oxygen saturation ( spo2 ) dropped to 85% at fio2 of 0.5 on venturi mask . the trachea was reintubated after administration of propofol 40 mg and succinylcholine 12.5 mg intravenous . the patient was shifted to icu and put on pressure support mode of mechanical ventilation . the next morning the patient was conscious , well oriented and had adequate spontaneous respiration along with stable vital parameters . on the following day , the patient was shifted to surgical postoperative ward and subsequently discharged to home after 1 week . the cause of prolonged paralysis can be drug over dosage , drug interactions , underlying medical conditions , co - morbidities , or altered pharmacokinetics and drug requirements in extremes of ages . in the case reported , the 74-year - old patient did not have any significant medical history except for recent onset type ii diabetes and alzheimer 's disease . the patient was taking oral metformin and glimepride for her diabetes and oral donepezil for alzheimer 's disease . both the oral hypoglycemic agents are not reported to have any significant interaction with donepezil or non - depolarizing muscle relaxants ( ndmr ) . donepezil is a reversible non - competitive inhibitor of acetyl cholinesterase with plasma half - life ( t1/2 ) of approximately 70 h. donepezil was possibly responsible for the seemingly inadequate muscle relaxation intra - operatively . the increased total dose requirement of ndmr may be explained by the increased availability of acetylcholine at neuromuscular junction . the prolonged neuromuscular blockade may have resulted from the residual effect of the large cumulative dose of ndmr . sanchez et al reported prolonged neuromuscular blockade with succinylcholine followed by inadequate muscle relaxation with atracurium intra - operatively in a 75-year - old patient with alzheimer 's disease on donepezil therapy for 14 months . baruah et al also reported increased ndmr dose requirement with inadequate muscle relaxation intra - operatively in an elderly patient on donepezil . the above case reports are in concurrence with this case and support the possibility of donepezil being the agent responsible for the inadequate intra - operative and prolonged post - operative neuromuscular block . more patients with such disorder , on acetyl cholinesterase inhibitor therapy , will require anesthesia in future and it is important that this interaction be highlighted . the manufacturer recommends omission of donepezil , at least 23 weeks prior to a scheduled surgical procedure . this may not have a detrimental effect on the patient 's overall cognitive function , as acetylcholine esterase inhibitor have no disease modifying action . if the drug is continued till the day of surgery , one should anticipate the possibility of the residual neuromuscular blockade persisting for a prolonged duration .
a 74-year - old female with diabetes mellitus type ii and alzheimer 's disease , taking donepezil for 4 months was operated for right modified radical mastectomy under general anesthesia . during the procedure a higher dose of non - depolarizing muscle relaxant 
 was required than those recommended for her age yet the muscle relaxation was inadequate intra - operatively . 
 residual neuromuscular blockade persisted postoperatively , due to the cumulative effect of large doses of non - depolarizing muscle relaxant , needing post - operative ventilatory assistance . after ruling out other causes of resistance to non - depolarizing muscle relaxants 
 , we concluded that acetylcholinesterase inhibitor donepezil was primarily responsible for inadequate muscle relaxation and delayed post - operative neuromuscular recovery .