MedlinePlus flags caffeine late in the day, cold medicines, diet pills, and various medicines and supplements as sleep wreckers; prescribing references add stimulants, SSRIs and SNRIs, steroids, decongestants, and over-replaced thyroid hormone.
The fix usually is not quitting: move activating drugs to morning, review the dose, and switch families if needed. Name the sleep change specifically to the prescriber, give a timing change a week, and do not stack over-the-counter sleep aids on top without asking, since they share ingredients with the cold medicines already on the suspect list.
What to do
Common questions
What medications cause insomnia?
If sleep broke around the time a medicine started, the medicine is a prime suspect. MedlinePlus lists the substances that can affect sleep: too much caffeine or caffeine late in the day, some cold medicines and diet pills, and other medicines, herbs, and supplements, and the wider prescribing literature adds the regulars: stimulants for ADHD, many antidepressants including SSRIs and SNRIs, corticosteroids like prednisone, decongestants like pseudoephedrine, some blood pressure drugs, and thyroid hormone when the dose runs high. The mechanisms: alerting drugs raise arousal directly, steroids rev the system broadly, and decongestants are stimulant cousins. The fixes rarely require quitting: moving an activating drug to morning, like an SSRI or steroid, often solves it; dose review is the second lever; and alternatives exist in most families. The rules of thumb: mention the sleep change specifically rather than saying you feel bad, because insomnia is fixable when named; give the timing change a week before judging; keep caffeine earlier in the day while you test; and do not stack a sedating over-the-counter sleep aid on top without asking, because the cold medicines MedlinePlus flags and sleep aids often share ingredients, and doubling antihistamines is its own problem.