Phentermine Side Effects and Why Blood Pressure Is Checked

Phentermine's FDA label lists side effects such as dry mouth, trouble sleeping, restlessness, a racing or pounding heartbeat, and higher blood pressure. It also tells prescribers to use caution even with mild high blood pressure. That's why your blood pressure is checked at your visits, and why telehealth patients send a picture of a recent reading first.

Phentermine is an FDA-approved generic appetite suppressant pill and a Schedule IV controlled substance, labeled for short-term use alongside a reduced-calorie diet, exercise and behavior change. With phentermine weight loss in Ocala, your provider reviews your heart health, blood pressure and medicines before deciding whether it's right for you.

What are the side effects of phentermine?

The label groups them by body system. Heart and blood vessels: palpitations (a pounding or fluttering heartbeat), a fast heart rate, higher blood pressure and ischemic events, meaning problems from reduced blood flow. Brain and nerves: feeling overstimulated or restless, dizziness, insomnia, tremor, headache, an unusually high or uneasy mood, and psychosis, a loss of touch with reality.

Other listed effects include dry mouth, an unpleasant taste, diarrhea, constipation, other stomach upset, hives, erection problems and changes in sex drive. The label gives no percentages, so no one can predict which you'll notice. It warns against late-evening doses because of insomnia. If you can't sleep, tell your provider rather than changing when or how much you take.

Why can phentermine raise blood pressure and heart rate?

Because it works like a stimulant. The label calls phentermine a sympathomimetic amine, a drug that mimics the body's fight-or-flight signals, with activity similar to amphetamine's. It notes that typical actions of amphetamines include stimulating the nervous system and raising blood pressure.

The label doesn't say how often blood pressure rises or by how much. In a 2011 study in the journal Obesity, researchers reviewed the records of 300 patients at one private weight-management practice, all on a low-carbohydrate diet. Average blood pressure fell with and without phentermine, with no significant difference between the groups. But that look back at records wasn't a placebo-controlled trial, and averages can hide people whose numbers rose. Only your own readings show how you respond.

Who should not take phentermine?

The label rules it out with a history of heart or blood vessel disease, such as coronary artery disease, stroke, an irregular heart rhythm, congestive heart failure or uncontrolled high blood pressure. Also on the list: an overactive thyroid (hyperthyroidism), glaucoma, an agitated state, an allergy or unusual reaction to this drug class, and a history of drug abuse. Phentermine is related to amphetamine, and the label warns of a risk of abuse and dependence.

It's also ruled out during or within 14 days after taking a monoamine oxidase inhibitor (MAOI), such as phenelzine or selegiline, because together they risk a hypertensive crisis, a sudden, dangerous spike in blood pressure. Pregnancy and nursing are on the list too. The label says weight loss offers no benefit in pregnancy and may harm the baby, and that while no one knows whether phentermine passes into breast milk, other amphetamines do.

Other conditions call for extra care. Phentermine leaves the body largely through the kidneys, so the label lowers the maximum dose for severe kidney disease and says to avoid it with very low kidney function or dialysis. It also advises against pairing phentermine with other weight-loss products, including over-the-counter and herbal ones, or with SSRI antidepressants such as sertraline, since the safety of those combinations hasn't been established.

Can you take phentermine if you have high blood pressure?

It depends on whether it's controlled. Uncontrolled high blood pressure rules phentermine out, but controlled high blood pressure doesn't on its own: the label lists it among the health risks that can qualify someone with a body mass index (BMI) of 27 or more. Still, the label urges caution even with mildly high blood pressure, since phentermine can raise it.

If you take blood pressure medicine, bring the list. The label says phentermine may weaken the effect of one type, adrenergic neuron blockers. Your provider decides whether phentermine is a reasonable choice and how closely to watch your numbers.

Which warning signs mean you should call right away?

Call your provider right away about new, unexplained shortness of breath, chest pain, fainting, swelling in your legs or ankles, or a drop in how much exercise you can handle. The label ties them to primary pulmonary hypertension, a rare, often fatal lung disease. Both it and serious heart valve disease were reported in people taking phentermine with fenfluramine or dexfenfluramine. Rare cases have also been reported with phentermine alone, so the label says a link can't be ruled out.

MedlinePlus, the National Library of Medicine's patient drug guide, adds a pounding heartbeat, raised blood pressure, restlessness, dizziness, tremor and insomnia to that call-now list. Milder problems like dry mouth or constipation are worth reporting if they're severe or don't go away.

Some situations need 911. The National Heart, Lung, and Blood Institute (NHLBI) says to call 911 if you think chest pain could be a heart attack, even if you're not sure. A reading above 180/120 that's still that high when you recheck 5 minutes later calls for your provider, or 911 if it comes with symptoms such as a sudden, severe headache, trouble breathing, severe chest or back pain, numbness, vision changes or trouble talking.

For side effects that aren't an emergency, call the clinic at (352) 369-0104, Monday to Friday, 9:00 AM to 5:00 PM. You or your provider can also report a side effect to the FDA through MedWatch.

Why is your blood pressure checked at your visits?

Because blood pressure runs all through the label: uncontrolled high blood pressure rules phentermine out, mild high blood pressure calls for caution, and a rise is a listed side effect. You also can't rely on how you feel. NHLBI says high blood pressure usually causes no symptoms until it has already caused serious problems. For most adults, a healthy reading is below 120/80, and readings consistently at 130 or higher on top, or 80 or higher on the bottom, count as high.

One reading is only a snapshot. NHLBI notes that nerves or a wrong-size cuff can throw a reading off, and that diagnosing high blood pressure takes two or more readings at separate appointments. Your first number is a baseline, and later ones show whether yours changes on phentermine. What counts as too high is your provider's call, and so is how long you can take phentermine.

Why do telehealth patients send a picture of a recent reading?

Because no one can measure your blood pressure through a screen. At Padgett, telehealth phentermine patients send a picture of a recent blood pressure reading before the visit, so the provider has a current number before deciding on a medicine that can raise it. Your own home monitor is fine, and so is a blood pressure machine at a pharmacy.

NHLBI's steps for an accurate reading: no exercise, coffee or cigarettes for 30 minutes beforehand, and use the bathroom first. Sit quietly for at least 5 minutes, feet flat, arm bare and resting on a table at heart level, and don't talk. At home, use an approved device with a cuff that fits, then photograph the screen so both numbers are easy to read.

Telehealth also requires being physically in Florida at the time of the visit and a valid Florida driver's license or state ID. Without a Florida ID, your phentermine visit is in person in Ocala. Telehealth visits anywhere in Florida explains how visits work, and getting phentermine online in Florida covers the law.

How do phentermine visits work at Padgett in Ocala?

Visits are with Sarah Weir, APRN, an advanced practice registered nurse, at 200 SW 8th St., Suite A, just south of downtown Ocala, or by telehealth anywhere in Florida. Florida's rule on drugs to treat obesity requires an initial evaluation before prescribing. Yours covers your health history, your blood pressure and everything you take, supplements included. No prescription is promised in advance.

Your first month is $196, or $127.40 when you book online with a card on file (35% off), for new patients. It includes the provider visit, your first month of phentermine and a B12 injection. Monthly refills are $166 for a visit, the medication and a B12 injection. Blood pressure is checked at the visits, which are also your chance to raise side effects. Booking costs nothing and there's no contract. What phentermine costs in Ocala has the details, including the $50 no-show fee.

If phentermine doesn't suit your health, your provider can discuss other options, such as weekly injections of personalized compounded semaglutide or personalized compounded tirzepatide, which work differently and have their own side effects. Phentermine vs. personalized compounded semaglutide compares them.

Want to ask about side effects first? The free consultation is a free 15-minute phone call with the medical staff; it is not a visit with the provider and nothing is prescribed on it. When you're ready, book a phentermine visit or call (352) 369-0104.

Personalized compounded semaglutide and personalized compounded tirzepatide are compounded drugs that have not been approved by the FDA. They have not been reviewed by the FDA for safety, effectiveness, or quality. FDA-approved products containing semaglutide and tirzepatide are available. Individual results vary.

This article is educational and is not medical advice. Talk with a licensed provider about your own health, medications and treatment options.