Zhewitra 40 mg is a high-strength dose of vardenafil used to treat erectile dysfunction (ED) in men. It belongs to the phosphodiesterase type 5 (PDE5) inhibitor class, which works by improving blood flow to the penile tissues during sexual stimulation. This helps in achieving and maintaining an erection. However, like other ED medications, it only works when there is sexual arousal and does not increase libido.