Antioxidant(s) showed no clear difference in adverse events ‐ Ectopic pregnancy№ of participants: 404(4 RCTs) compared with placebo or no treatment/standard treatment (low certainty).
Ibuprofen showed no clear difference in adverse events (reported in the first 7 days after the procedure) compared with placebo (low certainty).
SDF commonly causes black staining of arrested lesions; only mild, transient adverse events were reported, with no major adverse events (ungraded).
It is very uncertain whether summary of findings: monoclonal antibody KB001‐A changes adverse events number of participants experiencing adverse events compared with placebo (very low certainty).
Lidocaine may leads to higher adverse events (AEs; adverse drug reaction): drowsiness/dizziness compared with placebo or no intervention (low certainty).
It is very uncertain whether methylphenidate changes proportion of participants with one or more serious adverse events compared with placebo or no intervention (very low certainty).
It is very uncertain whether pharmacological interventions changes acceptability ‐ drop‐outs due to adverse events: post‐intervention compared with placebo (very low certainty).
It is very uncertain whether cediranib plus chemotherapy changes specific adverse events: gastrointestinal perforations or fistulae compared with placebo plus chemotherapy (very low certainty).
Antioxidant(s) showed no clear difference in adverse events ‐ Multiple pregnancy№ of participants: 1886(9 RCTs) compared with placebo or no treatment/standard treatment (low certainty).
Oral retinoids: alitretinoin 30 mg leads to higher primary: adverse events ‐ headache Folluw‐up: 48 weeks to 72 weeks compared with placebo (high certainty).
It is very uncertain whether oral ferric maltol changes serious adverse events ‐ mild disease to quiescent (up to 52 weeks) compared with oral placebo (very low certainty).
Summary of findings: Zinc supplementation showed no clear difference in adverse events number of participants hospitalised during the trial compared with placebo (moderate certainty).
VALPROATE + ANTIPSYCHOTICS showed no clear difference in adverse events: Weight gain Number of participants with weight gain compared with ANTIPSYCHOTICS + PLACEBO or ANTIPSYCHOTICS alone (low certainty).
Any dopamine agonist showed no clear difference in adverse events as N of participants with at least one adverse event compared with placebo (moderate certainty).
Amantadine showed no clear difference in adverse events as N of participants with at least one adverse event compared with placebo (moderate certainty).
Regular salmeterol leads to higher all‐cause non‐fatal serious adverse events ‐ adults and adolescents compared with placebo (high certainty).
Dextrose gel showed no clear difference in adverse events# (e.g. choking or vomiting at time of administration) compared with placebo (moderate certainty).