Using the hydrochloride salt form of Phentermine, Zantryl is a sympathomimetic amine that affects the central nervous system as a stimulant and an appetite suppressant. It stimulates the release of norepinephrine and dopamine from the brain’s nerve endings, and it blocks the reuptake of these elements. All this results in CNS stimulation and a metabolic effect. Zantryl uses a 30mg dose, which translates into a 24mg usable dose of Phentermine hydrochloride in general terms. It also promotes decreased gastric acid secretion and increased blood pressure. Serious side effects include feeling short of breath, even with mild exertion, swelling, rapid weight gain, chest pain, fast or uneven heartbeat, feeling like you might pass out, unusual thoughts or behavior, feeling restless or confused, dangerously high blood pressure, severe headaches, blurred vision, buzzing in the ears, anxiety, confusion, chest pain, shortness of breath, uneven heartbeats, or seizure. More common side effects include feeling anxious or nervous, headaches, dizziness, tremors, insomnia, dry mouth, unpleasant taste, diarrhea, constipation, or itching.