Pentoxifylline (PTX) modulates immunologic activity by stimulating cytokine production. Pentoxifylline is a methylxanthine derivative that inhibits phosphodiesterase and affects blood rheology. It also inhibits platelet aggregation and improves blood flow by increasing erythrocyte and leukocyte flexibility.

Theobromine (3,7-Dimethylxanthine), a xanthine alkaloid, is used as a bronchodilator and as a vasodilator.