必利勁 is the trade name and generic name of Dapoxetine Hydrochloride, a drug used to treat premature ejaculation in men. Dapoxetine Hydrochloride side effects are mainly in the nervous system and digestive system, contraindications if age and psychiatric limitations. 1. Side effects: The most common side effects of dapoxetine hydrochloride are headache, dizziness, nausea, diarrhea, insomnia, fatigue, epigastric pain, urgency to defecate, lack of libido, and emotional depression. They are generally well tolerated by most people. 2. Contraindications: Dapoxetine hydrochloride is not suitable for children under 18 years of age and the elderly over 64 years of age. Patients with depression or anxiety disorders should not take Dapoxetine Hydrochloride together with antipsychotic drugs. Dapoxetine hydrochloride is contraindicated in patients with severe renal impairment, closed-angle glaucoma and elevated intraocular pressure. Dapoxetine hydrochloride is a prescription drug and should be used under the supervision of a doctor.