For those who are having difficulty gaining weight despite all other non-medications measures being tried,, I do recommend trying cyproheptadine, nightly. From a thorough review article published in 2019, Cyproheptadine “appears to be a safe, generally well-tolerated medication that has utility in helping facilitate weight gain in patients drawn from a variety of underweight populations.”
For 5-12 year olds, we start at 2mg (½ of a tablet) nightly and see how that goes for 1-2 weeks. If it’s working but not well enough, we increase to 4mg nightly.
For those 13 and older we start at 4mg per night.
Dose range is usually 4 to 8mg.
Here is more info on Cyproheptadine:
Cyproheptadine (brand name Periactin) is a medication that has mostly antihistaminergic properties, like benadryl. Unlike benadryl it also interacts with serotonin, dopamine, and acetyl-choline receptors in the brain.
It is used for many conditions, including:
Hay Hayfever & allergic reactions
Cyclic vomiting syndrome
Chronic stomach upset and Functional gastrointestinal disorders (FGIDs) in children:
Restlessness caused by certain medications
Psychogenic itch (chronic itching/chronic pruritis)
It is usually well tolerated but it is sedating for most, so we recommend taking it at nighttime.
It should not be used in those taking antidepressants that act on serotonin, as it cyproheptadine blocks serotonin receptors. Interestingly, there is no evidence that it causes any depressive symptoms in those not taking antidepressants despite it blocking serotonin transporters. In fact I have had 2 cases where it helped their depression and when the patient stopped the cyproheptadine, it led to reemergence of their depression.
Here is a great review article that outlines the evidence behind using it as an appetite stimulant.
Posted by David Danish MD