Im 5feet 4 inches tall and I weigh 47kls. How do I gain weight? What meds can I take?

I've only seen an appetite-boosting commercial in TV although I haven't personally tried it. It's named Appeton Weight Gain. You may ask your doctor for further recommendations. Also, meds aren't the only way to gain weight. Eat protein-rich foods and hit the gym. Make sure you do a bit of weight lifting so your muscles can be developed.