Table 3.

Frequency of adverse effects with phosphodiesterase 4 inhibitors vs. placebo (% of patients)

Study	Drug	Greater than one adverse event	Nausea	Respiratory disorder	Diarrhoea	Abdominal pain	Headache
Compton [31]	Cilomilast	61 vs. 52	12 vs. 1	10 vs. 16	9 vs. 1	8 vs. 3	7 vs. 7
Rennard [34]	Cilomilast	87 vs. 82	5 vs. 1	N/A	8 vs. 4	8 vs. 4	N/A
Gamble [32]	Cilomilast	N/A	10 vs. 7	N/A	21 vs. 14	N/A	N/A
Rabe [33]	Roflumilast	67 vs. 62	3–5 vs. 1	23 vs. 23	9 vs. 2	N/A	<1 vs. 2
Calverley [36]	Roflumilast	N/A	3 vs. N/A	N/A	6 vs. N/A	N/A	N/A
Leichtl [38]	Roflumilast	49 vs. 49	2 vs. N/A	N/A	1 vs. N/A	N/A	2 vs. N/A

N/A, result not available or recorded. Not all studies published as abstracts alone are included due to lack of data surrounding adverse effect profile. Where different doses of active drug were used in the studies, the higher frequency of adverse effects is shown.