Medication Some prescribed treatments or medicines that are available over the counter can cause insomnia. These include: antidepressants epilepsy medicine medication for high blood pressure (hypertension), such as beta-blockers hormone replacement therapy non-steroidal anti-inflammatory drugs (NSAIDs) stimulant drugs, such as methylphenidate, which is often used to treat attention deficit hyperactivity disorder (ADHD) or modafinil, which is used to treat narcolepsy (a long-term sleep disorder that disrupts normal sleeping patterns) some medicines that are used to treat asthma, such as salbutamol, salmeterol and theophylline.