Lomaira (Phentermine) – Oral

What Is Lomaira?

Lomaira (phentermine) is an orally administered prescription medication used to expedite the treatment of obesity in people 16 and older with a body mass index (BMI) greater than 30 or equal to or greater than 27 with at least one weight-related medical condition such as hypertension (high blood pressure), diabetes mellitus, or high cholesterol.

Lomaira should be used alongside a strict diet and exercise regimen. Additionally, Lomaira is used as a short-term treatment, typically for three to six weeks.

Lomaira is an appetite suppressor that contains the active ingredient phentermine. Phentermine belongs to a class of drugs called sympathomimetics.

“Sympathomimetic” is a medical term for a substance that stimulates the sympathetic nervous system—also known as the fight-or-flight system. 

Phentermine is thought to cause weight loss by increasing brain neurotransmitters like norepinephrine, dopamine, and serotonin, a process that stimulates the body to burn calories while suppressing a person's appetite.

The active ingredient phentermine is available as a generic product administered in the form of an 8-milligram oral tablet.

Lomaira, a brand-name medication, is available by prescription as an oral tablet.


BMI is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measurement, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.

Drug Facts

Generic Name: Phentermine

Brand Name(s): Lomaira, Adipex-P

Drug Availability: Prescription

Administration Route: Oral 

Therapeutic Classification: Appetite suppressant, centrally acting

Available Generically: Yes

Controlled Substance: Schedule IV

Active Ingredient: Phentermine hydrochloride

Dosage Form(s): Tablet

What Is Lomaira Used For?

The Food and Drug Administration (FDA) has approved Lomaira for weight loss in people 16 and older. This medication is to be supplemented with a healthy diet and regular exercise.

Taking Lomaira for longer than three to six weeks is not recommended as it is only indicated for the short-term management of obesity.

Taking Lomaira with other weight-loss products is not recommended. Specifically, this includes prescription drugs and over-the-counter (OTC) supplements.

How to Take Lomaira

Take Lomaira according to your healthcare provider’s instructions. This medication is typically taken three times a day and is taken 30 minutes before eating.

The tablet is scored to allow for cutting it in half if your provider prescribes a lower dose.

Most people take Lomaira for three to six weeks. The length of treatment depends on how you respond to the medication.

It's important to note that Lomaira can be habit-forming. Therefore, do not take a larger dose or take it for a longer period than your healthcare provider tells you to.

Avoid taking Lomaira too late in the evening as it can cause insomnia (trouble sleeping).


Store at room temperature (between 68 and 77 degrees F) away from light. Keep this medicine in a dry, secure place and do not store it in a bathroom.

Keep all medications out of reach of children and pets.

Discard all expired or unused drugs. Ask your pharmacist about the best ways to get rid of your medicine. There may be local drug take-back programs in your area.

How Long Does Lomaira Take to Work?

Lomaira is more effective for weight loss within the first few weeks of taking the medication. You may initially see a weight loss of about 1 pound per week.

However, the body tends to build up a tolerance to the drug’s appetite-reducing effect. Additionally, taking Lomaira long term can lead to drug dependence. For these reasons, Lomaira is meant only for short-term use.

What Are the Side Effects of Lomaira?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects of Lomaira may include:

Severe Side Effects

The list below includes severe side effects reported with the use of Lomaira. It is very important to immediately inform your provider if you experience any of these.

If you feel the symptoms are life-threatening, call 911 as it might be a medical emergency.

Rarely, severe side effects of Lomaira and their symptoms may include:

Long-Term Side Effects

To minimize long-term side effects, it is important to take Lomaira only short term (typically a few weeks), as directed by your prescribing healthcare provider.

Not only does phentermine become less effective at suppressing appetite over time, but it also can be habit-forming if taken long term.

Long-term use of phentermine raises the risk of hypertension and heart disease.

Report Side Effects

Lomaira may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Lomaira Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For treatment of obesity:
    • For oral dosage form (capsules):
      • Adults and children 17 years of age and older—15 to 30 milligrams (mg) once a day, taken at approximately 2 hours after breakfast.
      • Children 16 years of age and younger—Use is not recommended.
    • For oral dosage form (disintegrating tablets):
      • Adults and children 17 years of age and older—One tablet once a day, taken in the morning.
      • Children 16 years of age and younger—Use is not recommended.
    • For oral dosage form (extended-release capsules):
      • Adults and children 16 years of age and older—One capsule once a day, taken before breakfast or 10 to 14 hours before sleeping.
      • Children 15 years of age and younger—Use is not recommended.
    • For oral dosage form (tablets):
      • Adults and children 17 years of age and older—
        • Lomaira™: One tablet three times a day, taken 30 minutes before meals.
        • Phentermine: 18.75 to 37.5 milligrams (mg) once a day, taken before breakfast or 1 to 2 hours after breakfast.
      • Children 16 years of age and younger—Use is not recommended.


Potential users should note the following before starting treatment with Lomaira:

Dosage adjustments: Lomaira comes in an 8-milligram tablet form. This medication can be cut or split in half if your provider prescribes a lower dose.

Pregnancy: Lomaira is discouraged during pregnancy because weight loss offers no benefit to a pregnant person and may result in fetal harm. 

Breastfeeding: It is not known if Lomaira is expelled in human milk; however, other amphetamines are present in human milk. Because of the potential for serious negative reactions in nursing infants, nursing is discouraged when taken alongside Lomaira.

Children: Lomaira is not recommended for use in people younger than 16 years old. 

Adults 65 and older: Dose selection for older adults should be done cautiously, typically starting at the low end of the dosing range, reflecting the greater chances of decreased liver, kidney, or heart function.

Kidney issues: Based on the expulsion of phentermine in urine, exposure increases are possible in people with kidney impairment. As a result, your dose may have to be adjusted if you have a history of chronic kidney disease (CKD).

Missed Dose

Take the missed dose as soon as you remember. If your next dose is too close, skip the missed dose. Instead, return to your usual dosing schedule. Do not duplicate the amount or take extra doses.

Overdose: What Happens If I Take Too Much Lomaira?

While uncommon, taking too much Lomaira may cause:

What Happens If I Overdose on Lomaira?

If you think you or someone else may have overdosed on Lomaira, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Lomaira, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and does not cause any unwanted effects.

Do not use phentermine if you are also using similar medicines such as benzphetamine, diethylpropion, mazindol, phendimetrazine, Bontril®, or Didrex®. Do not use this medicine if you also take an MAO inhibitor (MAOI), such as isocarboxazid (Marplan®), phenelzine (Nardil®,), selegiline (Eldepryl®), or tranylcypromine (Parnate®), or if you have used an MAOI within the past 14 days. Using these medicines together may cause serious unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.

This medicine may be habit-forming. If you think this medicine is not working properly after you have taken it for a few weeks, do not increase the dose. Instead, check with your doctor.

Call your doctor right away if you notice a decrease in your ability to exercise, or if you faint, have chest pain, swelling of your feet or lower legs, or trouble with breathing. These may be symptoms of a very serious heart or lung problem.

This medicine may cause some people to become dizzy, lightheaded, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

This medicine may affect blood sugar levels. Diabetic patients may notice a change in blood or urine sugar tests. Check with your doctor if you have any questions.

Avoid drinking alcohol while you are using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription and nonprescription (over-the-counter) medicines, dietary supplements, herbal remedies, or medicines for appetite control, asthma, colds, cough, hay fever, and sinus problems.

What Are Reasons I Shouldn’t Take Lomaira?

Lomaira may not be safe for everyone.

You should not take this medication if you have the following conditions:

  • Heart disease: Coronary artery disease (plaque buildup in the arteries), stroke, congestive heart failure, or uncontrolled hypertension
  • Hyperthyroidism (an overactive thyroid that produces too much hormone)
  • Glaucoma (a group of eye disorders that cause damage to the optic nerve)
  • Psychiatric disorders that make you agitated or anxious
  • History of substance use disorder
  • Pregnancy: Lomaira is discouraged during pregnancy because weight loss offers no benefit to a pregnant person and may result in fetal harm. 
  • Breastfeeding: Because of the potential for serious negative reactions in nursing infants, nursing is discouraged when taken alongside Lomaira.

Additionally, you should not take Lomaira if you take a monoamine oxidase inhibitor (MAOI; antidepressant medications) such as Marplan (isocarboxazid), Nardil (phenelzine), or Emsam (selegiline), or had taken one of these types of drugs in the last 14 days.

Also, you should not take Lomaira if you have had a previous allergic reaction to Lomaira or similar drugs, such as Adipex-P (phentermine), Akovaz (ephedrine), or Sudafed (pseudoephedrine).

What Other Medications Interact With Lomaira?

Lomaira interacts with multiple medications.

The following list includes some of the most important interactions to know about but does not include all possible interactions.

It is very important to tell your provider and pharmacist about everything you take, including prescription drugs, OTC medications, vitamins, herbs, and dietary supplements.

Examples of drugs that can interact with Lomaira include:

  • Other weight-loss drugs: These include Ozempic (semaglutide), Saxenda (liraglutide), or OTC products promoted for weight loss. It isn't known if taking Lomaira with other weight-loss drugs or products is safe. 
  • Insulin or oral diabetes medications: Lomaira may affect blood sugar levels, so you may need to monitor your blood sugar more often. It's also possible that your provider may adjust the dosage of your diabetes medications.
  • Medications that increase serotonin: These include Prozac (fluoxetine), Zoloft (sertraline), Luvox (fluvoxamine), and Cymbalta (duloxetine). The combination with Lomaira may increase the risk of serotonin syndrome. Let your healthcare provider know if you experience tremors, muscle stiffness, mood changes, or difficulty with balance. 
  • Certain medications that increase blood levels and side effects of Lomaira: Some examples are Marplan (isocarboxazid), Nardil (phenelzine), and Emsam (selegiline).
  • Fintepla (fenfluramine): This medication is currently used to treat certain types of seizure disorders. In the past, it was known as part of the combination "fen-phen." Fenfluramine should not be taken with drugs that contain phentermine because of the risk of serious heart valve problems.
  • The consumption of alcohol taken alongside Lomaira may result in a harmful drug reaction.

What Medications Are Similar?

Similar drugs to Lomaira that also contain phentermine include:

Other drugs that providers may prescribe for weight loss include:

A benefit of Lomaira is that it is generally less expensive than other weight-loss drugs. A downside is that Lomaira tends to lose its appetite-suppressing effects over time.

All of the above medications work best when combined with increased physical exercise and a healthy, low-calorie diet.

Talk to your healthcare provider if you are looking for alternatives to Lomaira that are right for you.

Frequently Asked Questions

  • How much weight should I expect to lose while taking Lomaira?

    When combined with diet and exercise, Lomaira's appetite-suppressing effects may help you lose up to a single pound per week.

    However, the body becomes tolerant to this medication within a few weeks, and its impact on appetite fades away. Therefore, it is typically only prescribed for short-term use.

  • How does the dosage of Lomaira compare to Adipex-P?

    Lomaira and Adipex-P contain the same active ingredient, phentermine.

    The difference is their dosage: Adipex-P comes as a 37.5-milligram tablet and is typically taken once a day at least an hour before breakfast.

    Lomaira is an 8-milligram tablet that is usually taken three times a day 30 minutes before meals.

  • What side effects should I expect while taking Lomaira?

    The more common side effects you should expect with Lomaira use include headache, restlessness, tremor, insomnia, dizziness, nausea, and a dry or unpleasant taste in the mouth.

    If these side effects don't go away or become severe, tell your healthcare provider.

How Can I Stay Healthy While Taking Lomaira?

Taking Lomaira is a short-term strategy for weight loss. This medication is not meant for long-term use.

Thus, it would be beneficial to adopt lifestyle changes as a long-term approach to reach and maintain a moderate weight. This includes sticking to a healthy diet and fitness routine.

A Mediterranean diet is an example of an approach to preparing meals that are not only nutritious but delicious. You can also consult a nutritionist to find a meal plan that is right for your dietary needs.

If you are new to exercising, start with a slight increase in physical activity, such as a daily walk. Intense or prolonged exercise beyond your fitness level could lead to injury.  

Find an accountability partner to commit to this journey with you to maximize your success in leading a healthy lifestyle. This could be a friend, family member, or spouse from whom you can seek and offer support and encouragement along the way.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Lomaira (phentermine) prescribing information.

  2. ScienceDirect. Sympathomimetic drug.

  3. MedlinePlus. Phentermine.

  4. DailyMed. Label: phentermine hydrochloride- phentermine hydrochloride tablet and capsule.

  5. Prescribers’ Digital Reference. Lomaira - drug summary.

  6. DailyMed. Label: Adipex-P phentermine hydrochloride tablet and capsule.

By Patricia Weiser, PharmD
Patricia Weiser, PharmD, is a licensed pharmacist and freelance medical writer. She has more than 14 years of professional experience.