|Type||An amphetamine-like drug|
|Working||Works by decreasing the appetite|
|Kicks In||About 4 hours|
|Treatment Period||Up to six weeks|
Phentermine belongs to a class of drugs known as sympathomimetic amines. Phentermine is used along with diet and exercise to treat obesity. The prescribed drug is used to treat obese people and those who have weight-related medical issues. It is an orally administered drug. This medication might not work the same after a few weeks.
How Does Phentermine Work?
Phentermine works by stimulating the central nervous system. This increases your blood pressure and heart rate and subsequently reduces your appetite. It may also increase the amount of energy used by your body.
Take phentermine as prescribed by your doctor. Usually, the drug is recommended to be taken an hour or two before breakfast. However, the doctor might adjust your dose to three smaller doses in a day.
Sustained-release capsules need to be taken either an hour before breakfast or at least 10-14 hours before bedtime. If you are taking a sustained-release capsule, then do not crush or chew them. Crushing/chewing will release all of the drugs at once and increase the risk of side effects.
Tablets made to dissolve in the mouth should usually be taken once in the morning. Make sure that your hands are dry when you handle the tablet.
Dose and length of treatment differ from patient to patient.
What if you miss a dose?
In case you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, then skip the missed dose. Do not double the dose to make up for the skipped dose.
What if you overdose?
Symptoms such as rapid breathing, unusual restlessness, fast/slow/irregular heartbeat, chest pain, hallucinations, seizures, loss of consciousness may occur in someone who has overdosed. If an overdose is suspected, seek medical help immediately.
Before you take Phentermine
- Make sure to tell your doctor about any allergies, and especially if you are allergic to sympathomimetic amines.
- Inform your doctor about your medical history. Especially about high blood pressure, glaucoma, diabetes, personal or family history of a substance use disorder, heart disease, mental health issues, high blood pressure in the lungs, stroke, overactive thyroid, kidney disease, seizures.
- If you have diabetes, then share your blood sugar level regularly with the doctor.
- If you are taking sustained-release capsules, then make sure that you do not crush or chew them. Doing so will release all of the drugs at once and increase the risk of side effects.
- Phentermine can cause addiction. You are at a higher risk if you have a substance use disorder.
- Avoid the intake phentermine if you have glaucoma, overactive thyroid, severe heart problems, advanced coronary artery disease, extreme agitation, uncontrolled high blood pressure or a history of drug abuse.
- Do not use phentermine if you have used an MAO inhibitor in the last 14 days. Doing so can lead to a dangerous drug reaction.
- The medication can increase your blood pressure. Monitor your blood pressure and report to the doctor if the results are high.
- It is possible that tablets made to dissolve in the mouth may contain aspartame.
- The drug can make you drowsy and blur your vision. Consumption of alcohol can make it worse. Do not perform any tasks that require you to pay attention, until you can perform them safely.
- Although rare, the drug can cause heart or lung problems. Use of this drug along with other appetite-suppressant drugs/herbal products can increase the risk.
- Do not use this medicine if you are pregnant or breastfeeding. The drug can pass to the baby and cause harm.
- The medication is removed by the kidneys. Since kidney functions decline with age, older adults might be more sensitive to the side effects such as dizziness and high blood pressure.
If you take Phentermine, then it is possible that the following side effects may occur –
- Dry mouth
- Difficulty in sleeping
It is also possible that some serious side effects may occur. These include –
- Fast/irregular/pounding heartbeat
- Mental/mood changes
- Change in sexual ability/interest.
- Severe headache
- Slurred speech
- Weakness on one side of the body
- Vision changes
The drug can rarely cause serious lung or heart problems. The longer the time period, the higher the risk.
In case of any serious side effects, get immediate medical help. Although an allergic reaction to this medicine is rare, seek help if you notice any allergic reactions.
- Make sure that you store the medicine in a tightly closed container, at room temperature.
- Store in a cool and dry place, away from light and temperature.
- Make sure that the medication is out of reach of children and pets.
Frequently Asked Questions (FAQs)
What happens when I stop using the medication?
To avoid withdrawal symptoms, it is best to lower your dose slowly. However, if you suddenly stop using the medication, then you might suffer from certain withdrawal symptoms such as depression and severe tiredness.
Does phentermine make you tired?
Some of the side effects of phentermine include drowsiness, fatigue, and reduced energy levels. If these side effects persist then consult your doctor.
How quickly does phentermine work?
This drug is absorbed through the gastrointestinal tract and reaches peak concentration in about 3 to 4.5 hours.
What does phentermine do to the body?
Phentermine stimulates the central nervous system. This increases the heart rate and blood pressure and decreases your appetite.