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Do nonsteroidal anti-inflammatory drugs increase the risk of bleeding after tonsillectomy

Three Part Question

In [children after tonsillectomy] does the [use of NSAIDs compared with opiates] increase [the risk of bleeding and decrease the risk of nausea or vomiting]

Clinical Scenario

You are a Paediatric SHO covering the hospital wards. A 5 year old child has had tonsillectomy, and the nurse looking after this child says the child is in lots of pain. She has given paracetamol but the child is still crying in pain. You consider giving a non-steroidal anti-inflammatory drug (NSAID) but you know that these agents interfere with platelet function and are worried about increased risk of bleeding. You also consider giving morphine but you know that it may cause nausea and vomiting.

Search Strategy

Cochrane and Pubmed
Pubmed: search words – NSAIDs and Tonsillectomy and bleeding

Search Outcome

Cochrane - none
Pubmed:47 hits (40 were relevant), 2 systematic reviews including all 25 good quality RCTs. Though both the reviews included adult patients majority of the patients in both the reviews were children.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
E Marret et al
7RCT ( 5 in children ) of postoperative NSAID use 262 patients received NSAIDs and 243 patients received control treatment (1995 – 2001)Systematic review of randomised double blind control trials ( Level 1a)Risk of reoperationControl rate of reoperation 0.8% NSAID rate 4.2%. Odds Ratio 3.8 (95%CI 1.3 to 12). NNH 29 (95% CI 17 to 144)Data on children not analysed separately No patient required blood transfusion
Steen Moiniche et al
25 RCT (14 in children) of NSAID use perioperatively 970 received a NSAID (diclofenac, ketorolac,ibuprofen,tenoxicam,naproxen indomethacin,nimosulide) and 883 received no NSAIDQuantitative systematic review (Level 1a)Risk of reoperationOdds Ratio 2.33 with NSAIDs (95% CI 1.12 to 4.83) NNH 60 ( 95% CI 34 to 277)NSAIDs and morphineeqianalgesic. Data on children compared to adults, or on the individual NSAIDs were too sparse to allow subgroup analysis
Risk of vomitingRelative Risk 0.73 with NSAIDS (95% CI 0.63 to 0.85) NNT 9 (95% CI 5 to 19 )


Tonsillectomy is a commonly performed operation in children, and is done on an outpatient basis in many centres. It is associated with severe postoperative pain , nausea and vomiting. Vomiting is among the most common reason for unscheduled readmission after outpatient tonsillectomy. Two recent postal surveys conducted in the United Kingdom to evaluate pain treatment after tonsillectomy in children found that NSAIDs were used in 45 – 70% of patients. The incidence of post tonsillectomy bleeding severe enough to require reoperation for haemostasis ranged from 1 – 5.5% A well performed systemic review (S Moiniche et al) found perioperative NSAIDs increased the risk of reoperation (OR 2.33 and NNH of 60) but were equianalgesic to opiates, and the risk of emesis was significantly decreased (with NNT of 9). The balance is about 2 more reoperations against 9 fewer cases of post operative nausea and vomiting . Another systematic review with meta-analysis of randomised, double blind controlled trials of post-operative NSAID treatment looking primarily at the need for surgical electrocautery to stop bleeding found that 1 in every 29 patient treated with NSAIDs will need a reoperation. The authors suggested the use of NSAID therapy should be abandoned both at the hospital and at home NSAIDs act by inhibiting cyclo-oxygenase (COX) and thereby reducing prostaglandin synthesis and inhibiting platelet aggregation. Two COX isoenzymes have recently been identified , the constitutive COX-1 isoform expressed in gastric mucosa and platelets and COX - 2 isoform, which is upregulated during inflammation. However selective COX –2 inhibitors do not inhibit platelet aggregation in vitro. Available studies of NSAID therapy for relieving pain related to tonsillectomy evaluated nonselective COX inhibitors. The way forward could be to investigate the use of COX-2 inhibitors which may provide similar pain relief without the risk of increased bleeding associated with nonselective COX inhibitors, and the use of local anaesthetic infiltration or dissection with high frequency ultrasound.

Clinical Bottom Line

For every 100 patients undergoing tonsillectomy and treated with NSAID rather than opioids , 2 may need a reoperation because of bleeding but 9 fewer will have a postoperative nausea and vomiting Compared with opioids , NSAIDs seems to be equianalgesic following tonsillectomy Research into the use of cyclo-oxygenase type 2 inhibitors which have minimal effects on platelet aggregation is needed in children undergoing tonsillectomy


  1. Marret E, Flahault A, Samana C M, Bonnet F. Effect of Postoperative, Nonsteroidal, anti-inflammatory Drugs on Bleeding Risk after Tonsillectomy. Meta-analysis of Randomised, Controlled Trials. Anesthesilogy 2003;98(6):1497-502.
  2. Moiniche S, Romsing J, Dahl J B, Tramer M R. Nonsteroidal Antiinflammatory Drugs and the Risk of Operative Site Bleeding After Tonsillectomy: A Quantitative Systematic review. Anesth Analg 2003;96(1):68–77.