Ulcerative colitis in smokers, non-smokers and ex-smokers

Table 1 Studies of the use of nicotine in ulcerative colitis

Ref.	Formulation	Dose (mg)	n	Type of disease	Study	Comparator	Results
[44]	Nicotine gum	4	1	Active UC	Uncontrolled	--	100%
Perera et al[45]	Nicotine gum	4	11	Active UC	Uncontrolled	--	27%
Watson et al[46]	Nicotine gum	--	1	Active UC	Uncontrolled	--	100%
Srivastava et al[47]	Transdermal nicotine	22	18	Active UC	Uncontrolled	--	78%
Guslandi et al[48]	Transdermal nicotine	15	3	Active UC	Uncontrolled	--	66%
Guslandi et al[49]	Transdermal nicotine	15	10	Active UC	Uncontrolled	--	70%
Lashner et al[50]	Nicotine gum	20	7	Active UC	Cross-over	Placebo	NI 43% vs PL 0%
Pullan et al[51]	Transdermal nicotine	15-25	72	Active UC	Controlled	Placebo	NI 49% vs PL 24%
Sandborn et al[52]	Transdermal nicotine	11-24	64	Active UC	Controlled	Placebo	NI 39% vs PL 9%
Thomas et al[53]	Transdermal nicotine	15-25	61	Active UC	Controlled	Prednisone	NI 20% vs PR 45%
Guslandi et al[54]	Transdermal nicotine	15	38	UC in remission	Controlled	Prednisone	NI 71% vs PR 88%
Thomas et al[55]	Transdermal nicotine	15	80	UC in remission	Controlled	Placebo	NI 45% vs PL 50%
Green et al[57]	Nicotine enemas	4	22	Active UC	Uncontrolled	--	73%
Sandborn et al[58]	Nicotine enemas	6	7	Active UC	Uncontrolled	--	71%

NI: Nicotine; PL: Placebo; UC: Ulcerative colitis.

Table 2 Possible mechanisms in the pathogenic interactions of smoking and inflammatory bowel disease[64]

Modulation of cellular and humoral immunity

Changes in cytokine levels

Modification of eicosanoid-mediated inflammation

Reduction of antioxidant capacity, production of oxygen free radicals

Release of endogenous glucocorticoids

Colonic mucus effects

Alteration of mucosal blood flow

Pro-thrombotic effects and promotion of microvascular thrombosis

Alteration of gut permeability

Modification of gut motility