Side effects from medications can be either directly or indirectly fatal. Dizziness is a common medication side effect that may be fatal for people older than 65, explains Scientific American. Stevens-Johnson syndrome is an exceptionally rare and often fatal medication side effect that involves skin necrosis, notes Mayo Clinic.
Drowsiness is another common side effect that may become fatal. For this reason, warnings for some medications, including Lunesta, caution users against operating heavy machinery while under the drug's influence.
A drug with known fatal side effects may be the last available treatment option. For example, clozapine, a drug that treats schizophrenia, can cause a fatal problem with white blood cells, explains MedicineNet. Clozapine is only prescribed when other medications are ineffective. Amiodarone, an antiarrhythmic drug, may cause death, but it is only prescribed to treat life-threatening heart conditions, notes Drugs.com.