Most medicines come in a variety of types or formats. Be aware, though, that some medicines (particularly rare or unusual ones) only come in one type. Also, some may be more effective in one type than another.
Medicines can be confusing. We are told that they can cure an illness or improve our symptoms, but that they can be dangerous if taken incorrectly. The key to dealing with medicines effectively is to understand them.
Mercaptamine is a medicine that stops build up of an amino acid called cystine in the body. Large amounts of cystine can build up in the body causing damage to tissues and organs when a child has a condition called cystinosis. Mercaptamine eye drops are prescribed to reduce build up of cystine crystals in the eyes.
This page from Great Ormond Street Hospital explains about the medicines called triptans. Triptans are a group of medicines used to treat migraine or headache. They are also known as 5HT1-receptor agonists, which refer to the particular substance in the brain (5HT 1B/1D or serotonin) on which the medicines act.