Consumption of broad-spectrum antibiotics is associated with rising antimicrobial resistance (AMR) levels. The use of broad-spectrum drugs, particularly of cephalosporins, quinolones, and co-amoxiclav contributes the most to the rise in AMR. We use aggregate sales data on antibiotics from the UK to estimate structural demand models and reveal drug substitution patterns. We then simulate alternative tax schemes to evaluate the effectiveness of shifting demand from broad- to narrow-spectrum drugs. Our estimates suggest that these policies can be highly effective in demand management and come at a relatively low cost regarding changes in consumer and producer surplus.