Migraine

**Notes:** - the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled

**Excludes1:** - headache NOS (R51.9) - lower half migraine (G44.00)

**Excludes2:** - headache syndromes (G44.-)

**Use additional code:** - code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)