Can You Overdose on Phentermine? (what is too much?)

January 8, 2024 |

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If you’re struggling with weight loss, phentermine may be your answer.

A popular medication many people use to help them lose weight. It can be a practical part of a weight loss program combined with diet and exercise.

Phentermine may be less intense than other amphetamines, but it is still possible to overdose on the medication. The maximum recommended daily dose is 37.5 mg per day. If you take more than this, you are overdosing.

Read on to learn the signs and symptoms of a phentermine overdose, what to do if you think you’ve overdosed, and avoiding future overdoses.

How much Phentermine is too much?

No specific dosage amount determines whether someone has taken too much phentermine. It all depends on age, tolerance, and overall health. However, the risk of overdose increases with higher doses.

The most common phentermine dose is 37.5 mg of phentermine hydrochloride (HCl), taken once a day. Most people take the drug in the morning to not be awake at night from the stimulant effects.

Doses can be higher, up to 15 mg twice a day, for those who need more control over their appetite.

If you find that 37.5 is too much at once, your doctor could decrease the dose to 18.75 mg, or you could split 15 mg in half and take it twice a day.

However, you should never take more than 15 mg of phentermine without consulting a doctor first, taking more than that puts you at risk for overdose and other dangerous side effects to your health and well-being.

When you notice abnormal heartbeat, dizziness, fainting, or severe headaches after taking phentermine for the first time or after an increased dose, seek medical assistance immediately.

These can be signs of a stroke or heart attack caused by an overdose of the drug.

If you think you may have taken too much phentermine, call 911 right away.

What can happen if you overdose on Phentermine?

Overdosing on phentermine can have serious side effects like hallucinations and loss of consciousness. You mustn’t take more than your doctor has prescribed.

Taking more than you need will only put you at risk for serious health problems. Watch out for the signs below to recognize a possible phentermine overdose.

Symptoms of a phentermine overdose

While an overdose of phentermine is unlikely to happen, it’s still important to learn the signs of an overdose.

Symptoms of a phentermine overdose may include:

  • rapid breathing
  • blurry vision
  • chest pain
  • confusion
  • severe headache
  • hallucinations
  • fever
  • unusual feeling of well-being (euphoria)
  • weakness (including lack of strength and energy)
  • tremors, shaking movements in the hands and fingers when at rest (fine motor tremor)

Call your local poison control center or seek emergency medical attention immediately if you suspect someone else has overdosed on phentermine.

Do this regardless of whether this medication was prescribed to you or obtained from an illegal source.

What are the effects of Phentermine overdose?

The long-term damage resulting from phentermine overdose depends on the amount consumed and how it is absorbed into the body. People who take large doses of phentermine may experience short-term side effects that are reversible within a few days or weeks of stopping the use of the medication.

However, severe cases of phentermine overdose can cause heart problems.

An overdose increases your risk of heart attack and stroke by increasing blood pressure and leading to an irregular heartbeat (arrhythmia).

Long-term use of phentermine may also cause muscle spasms in the arteries, leading to blood clots and heart attacks or strokes if they break loose and travel through the blood vessels.

Other medical complications of phentermine overdose include:

  • Heart attack and heart failure: Phentermine can cause irregular heartbeat and heart problems, including heart attacks and heart failure.
  • Severe anxiety: Phentermine use can cause agitation, nervousness, restlessness, and insomnia (trouble sleeping). The perturbation may be accompanied by hallucinations (seeing or hearing things not there).
  • Seizures (convulsions): Phentermine can cause seizures in some people who take it for long periods or in high doses. The risk of seizures increases if you also have other seizure disorders such as epilepsy.
  • Stroke: Phentermine use has been linked to strokes in some people who have taken it for long periods or in high doses.

Long-term use of phentermine has also been linked to psychosis, including hallucinations and delusions.

Psychosis can also occur as a result of stopping phentermine suddenly.

Can you die from taking too much phentermine?

The active ingredient in phentermine is an amphetamine.

Amphetamines can produce psychotic behavior. When used in excess or combined with other drugs (especially alcohol), they can cause serious health problems and even death.

Amphetamines have been associated with sudden death due to cardiac arrhythmias.

The mechanism behind this is under study, but it is related to the release of norepinephrine from nerve terminals which can trigger abnormal rhythm disturbances.

Multiple phentermine pills consumed rapidly could be lethal. The high dosage would increase the risk of cardiovascular collapse due to psychological and physiological stressors associated with such a large dose at once (e.g., anxiety).

Death from acute phentermine overdose results from overstimulation of the central nervous system.

The heart rate increases, blood pressure rises, and the body temperature rises to dangerous levels.

The user may experience rapid breathing, confusion, vomiting, and seizures. If not treated promptly, acute phentermine intoxication can lead to coma or death within a few hours of ingestion.

In addition to acute toxicity, there is also evidence that chronic use of amphetamines may lead to structural changes in brain areas involved in learning and memory function.

How can I manage my risk of overdosing on phentermine?

Phentermine overdose can lead to a severe medical emergency. Call 911 or your local emergency number if you see the sign of phentermine overdose.

You’ll be more likely to avoid an overdose of phentermine if you do the following:

  • Take your prescribed dose. Follow the instructions on your prescription label carefully, and take phentermine precisely as directed. If you don’t understand how to handle it or have any questions about this medication, ask your doctor or pharmacist for help.
  • Avoid taking extra doses. Don’t take a higher amount of phentermine than is not recommended by your doctor. Even if a higher dose helps you lose weight, it can increase your risk of side effects and possibly overdose.
  • Avoid other drugs while taking phentermine. Ensure that all doctors who prescribe medicine for you know you’re taking phentermine. Do not take phentermine with any other medications without a doctor’s approval.

If your doctor approves using other medications with phentermine, inform them if these negatively affect your prescription drug use (e.g., making it less effective).

Is there an alternative to Phentermine for weight loss?

Phentermine is a drug that helps people lose weight by curbing their appetite.

Physicians prescribe the medication for people who are overweight or obese and can’t seem to lose weight through diet and exercise alone.

There is no question that phentermine can be highly effective in helping people shed pounds. However, it’s vital that you know about the adverse side effects it can have when taken for too long or at too high of a dose and how to avoid overdosing on phentermine.

Alternatively, you can use another option to help you achieve your weight loss goals without side effects.

The best way to lose weight is by the right blend of exercising and natural weight loss supplement that is safe and effective.

We recommend PhenQ, a powerful blend of five weight loss pills in one that helps you gain lean muscle and promote fat loss without the side effects associated with phentermine. It is safe and legally bought without a prescription.

There is no need to worry about developing a dependence on these pills or any other side effects.

Is PhenQ worth it?

PhenQ is a weight loss supplement that has become increasingly popular in recent years. The supplement is designed to help people lose weight by burning fat, suppressing appetite, and stopping the production of new fat cells.

PhenQ is also said to improve mood and boost energy levels.

So, what makes PhenQ worth trying?

First, unlike many other weight loss supplements, PhenQ contains natural ingredients that have been clinically proven to be effective.

Second, PhenQ is made from natural ingredients that are safe to take. And third, PhenQ comes with a money-back guarantee, so you can try it without risk.

For these reasons, PhenQ is definitely worth considering for anyone who is looking for a safe and effective way to lose weight.


What is Phentermine?

Phentermine is a prescription medication used to help people lose weight by suppressing their appetite.

It belongs to the class of drugs known as sympathomimetic amines. It essentially means it works like an amphetamine (a stimulant—think caffeine, cocaine, and meth). The U.S. Food and Drug Administration (FDA) approved it for short-term use in 1959.

Phentermine works to affect chemicals in your brain that control your appetite.

Many doctors will only prescribe phentermine for short periods because it’s habit-forming. People may abuse it, especially if taken with other substances like alcohol or opioids (heroin, oxycodone).

Because of this habit-forming nature, tolerance to phentermine can build up quickly.

For example, you might need to take more and more of the drug over time to achieve its intended effect or keep getting the same results you once did from taking a lower dose.

But when taken as prescribed under a doctor’s care, phentermine is generally safe; just don’t expect it to solve all your problems with weight loss on its own.

Can phentermine affect pregnancy?

Phentermine is an appetite suppressant that affects the central nervous system and should not be used in pregnancy. The use of phentermine is contraindicated during pregnancy. It may cause fetal harm and congenital disabilities and, in some cases, can be passed through breast milk.

The FDA classifies phentermine as a category X medication, which means it’s known to cause severe congenital disabilities or fetal death.

Can I take an extra dose of phentermine?

Avoid taking more than one dose of phentermine per day.

The maximum recommended dosage is 37.5mg daily. Taking more than the recommended dosage can increase your risk of unpleasant side effects and cause dependence and withdrawal symptoms when you stop taking the medication.

Phentermine should not be used for longer than a few weeks consecutively. It can become less effective over time, and you may experience withdrawal symptoms when you stop using it.

Final Thoughts

Phentermine is a prescription medication that helps with weight loss. It’s important to follow the dosage instructions and not take more than prescribed. Taking too much phentermine can lead to an overdose.

An overdose of phentermine can cause heart problems, seizures, and even death. If you think you or someone else has overdosed on phentermine, seek medical help immediately.

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