| Drug | Clinical reaction(s) | Presumed mechanism |
| Aspirin and other NSAIDs | Exacerbations of rhinitis, asthma (in patients with aspirin-exacerbated respiratory disease) Urticaria/angioedema (NOTE: Urticaria may also result from a type I, IgE-mediated allergic reaction) | Inhibited prostaglandin production and enhanced leukotriene production |
| Opiates | Pruritus, urticaria | Direct stimulation of mast cells and/or basophils causing release of mediators |
| Vancomycin | Flushing during infusion | Direct stimulation of mast cells through MRGPRX2, causing release of mediators |
| Radiocontrast media | Anaphylaxis, shock (NOTE: Some may be type I, IgE-mediated allergic reactions) | Unknown mechanism |
| Ciprofloxacin | Urticaria (most reactions) | Direct stimulation of mast cells through MRGPRX2, causing release of mediators |
| Local anesthetics | Syncope | Vasovagal reflex |
| Protamine | Hypotension, pulmonary hypertension | Unknown mechanism |
| Choline | Pruritus, urticaria | Unknown mechanism |
| Isoniazid | Hepatitis | Unknown mechanism |
