yes
It's possible since phentermine is a stimulant and can affect the circulatory system. Usually after three weeks or so your body builds up a tolerance to phentermine so don't be surprised if it doesn't "work" like it used to.
Phentermine is not recommended for long term usage, and has been linked to several side effects. The most common were dry mouth, dizziness, but could escalate to high blood pressure, tremors and palpitations.
Short answer: General rule of thumb with most medications is to give a 2-3 hour wait before taking anything else. This does seem to work for these 3 medications. However, be aware that doxycycline is very strong and stays in your system much longer than metronidazole. So you might want to give it more room to breath. If at all possible, I suggest waiting 4 hours after taking doxy before taking anything else, especially if you intend on taking probiotics or another supplement to replenish your immune system(which i highly suggest).
Ha! No. First thing is that they are two different medications and have no similarities at all. One is a stimulant (amphetamine) and the other is an appetite suppressant (phentermines). Phentermines have a maximum half life of 36 hours. Take your prescription dosage and do the math. It depends on your prescription but the longest a phentermine would stay in your system would be three weeks.Also, since you are posting this question, you are obviously worried about amphetamines showing up on a drug test. Amphetamine has a half life of about 10 hours. If you take 60mg of, let's say, Adderall on Monday. Any measurable amount of the medication would be out of your system by Friday.updatedWell i was told that phentermine would show up during a drug test as a amphetamine, that's whats got me scared. About 2 or 3 days before the test i started taking my old prescription (2 years old) of phetermine again. I even took one the morning of the test because i didnt know it would hurt anything. So now im just scared. I need a job so bad.