1-the multivitamins ( vita) which according to research have minimal if any benefit if you are eating a regular diet and have not had any surgery that involves removal of parts of your digestive tract. 

2- Cyprohepatidine which is an allergy medications...an old one...which means it could cause dizziness and drowsiness. One of it's side effects ( in a small group of people) is increased appetite and weight gain.  It's use as an appetite tonic ( like Periactin) is something called Off-label use. 

Strictly speaking it is not unhealthy...but you shouldn't take it except before sleep.

If you want to gain weight...there are multiple ways. 

1- A balanced diet is one. Multiple small meals 

2- Exercise ( while making sure you increase your protein intake)

3- Stop smoking

4- Stop caffeine ( coffee, tea, sodas)

5- Do stress relieving activities. Yoga, meditation, etc

Hope this helps!