Does Phentermine Have Dangerous Side Effects?

Before taking phentermine, you should be aware of the dangerous side-effects caused by the drug. Phentermine is prescribed to patients with a BMI (body mass index) over 30 and are at-risk for conditions like high blood pressure or diabetes. Unfortunately, there are quite a few adverse effects patients experience as a result of taking it.

Who Should Avoid Phentermine

Phentermine 30mg, also known for its common brand names such as Adipex-P, Suprenza, Ionamin, and Zantryl, should not be prescribed or used by people who:

  • are allergic to adrenergic drugs
  • are pregnant, planning to become pregnant, or breast-feeding
  • have a history of drug abuse
  • are taking or have recently taken some types of depression medications
  • have cardiovascular disease, hyperthyroidism, or glaucoma
  • have an overactive thyroid
  • have heart disease, high blood pressure, or diabetes
  • or have severe hardening of the arteries

Dangerous Side-Effects of Phentermine

If you experience any of these side-effects while taking phentermine, inform your doctor or seek emergency care right away:

Common side effects

  • diarrhea
  • itching
  • headaches, tremors or dizziness
  • constipation
  • restlessness or hyperactiveness
  • insomnia
  • chest pain
  • rashes or facial swelling
  • trouble urinating
  • dependence or addiction to the drug

Serious Side-Effects of Phentermine

These side-effects may indicate serious reactions to the drug and if experienced, emergency medical care should be sought immediately:

  • hallucinations (sensing things that aren’t there)
  • trouble thinking
  • fatigue
  • high blood pressure (symptoms include buzzing in ears, anxiety, seizure, and blurred vision)
  • upset stomach
  • nervousness
  • psychotic episodes
  • feeling short of breath
  • unpleasant taste in mouth or dry mouth
  • swelling in the ankles or feet
  • depression
  • changes in libido or impotence
  • unusual thoughts or behavior
  • abnormal impatience or confusion

Other Concerns

There have been cases of cardiac valvular disease and pulmonary hypertension from patients on phentermine. When on this on this drug, operating any machinery and driving motor vehicles should be avoided. Consuming alcohol while on phentermine may increase chances of experiencing some of the unfavorable side-effects associated mentioned above.

Along with alcohol, several other drugs should be avoided due to adverse interactions with phentermine. It should also be noted that once a person stops taking phentermine, symptoms of withdrawal may occur.

Some of the drugs that interact with phentermine include:

  • Henelzine (Nardil)
  • Diethylpropion
  • Tranylcypromine (Parnate)
  • Benzphetamine (Didrex, Regimex)
  • Amphetamine (Adderall)
  • Isocarboxazid (Marplan)
  • Dexmethylphenidate (Focalin XR, Focalin)
  • Lisdexamfetamine (Vyvanse)
  • Methamphetamine (Desoxyn)
  • Sibutramine (Meridia)
  • Procarbazine (Matulane)
  • Selegeline transdermal patches (Emsam)
  • Dextroamphetamine (Dexadrine)
  • Methylphenidate (Concerta, Metadate CD, Methylin, Ritalin)
  • Phendimetrazine (Bontril, Bontril PDM)
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