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Medications for Weight Loss (Underweight)

Unexplained or unintended weight loss should be a signal to you that you need to visit your doctor. Your doctor may become concerned if you experience unintentional weight loss of more than 5% of your usual body weight over a 6 to 12 month period, especially if your weight loss has not stabilized or continues to go down.

For example, a weight loss of 5% in a 160 pound (72 kilograms) person would be equal to a 8 pounds (3.6 kilograms).

There are many causes of weight loss and a clinical exam and testing can often identify the causes. However, in some cases, it’s often difficult to pinpoint an exact cause.

It’s important to have unintended weight loss evaluated as it can be associated with serious medical, mental health or social disorders that can usually be addressed by your healthcare provider.

What is unintentional weight loss?

Unintentional weight loss can be connected to various types of medical conditions, including cancer, gastrointestinal (digestive tract) diseases or psychiatric illness, among others. Lack of adequate nutrition or food can also lead to weight loss, often stemming from a family, financial or social obstacle. Multiple reasons may contribute to weight loss.

Unexpected or unintentional weight loss in children and older adults with chronic diseases can be especially problematic.

Weight loss in older patients is common, estimated to occur in up to 20% of people 65 years of age and older (when followed over at least 10 years).

  • In the 12-year U.S. NHANES (National Health and Examination Survey) Mortality Study in 5,000 people over the age of 50, unintentional weight loss was linked to a 24% increase in death, even in people considered obese
  • Weight loss in nursing home residents is also associated with increased rates of death. The US Centers for Medicare and Medicaid Services require that long-term care facilities evaluate residents with an unplanned weight loss (5% change in 30 days or 10% change in 180 days).

Weight loss in patients with serious chronic diseases, such as lung disease or heart failure can be associated with higher rates of death. Weight loss in children can also be linked with poor nutrition, lack of food, and school and family environments. 

This overview discusses unintentional weight loss. Weight loss and treatment options for people who are overweight or obese are discussed here.

What are the types of unintentional weight loss?

AIDS Related Wasting - the involuntary loss of body weight due to low appetite, poor nutrient absorption or altered metabolism associated with progression of HIV/AIDS.

Cachexia - involuntary weight loss from loss of muscle mass (with or without fat loss), usually associated with general ill health and malnutrition; can be associated with cancer progression or advanced heart failure.

Failure to Thrive - occurs in children whose current weight or rate of weight gain is significantly lower when compared to other children of the same age and gender.

Sarcopenia - loss of muscle mass, strength and performance in older patients, which may or may not be linked to weight loss.

What causes unintentional weight loss?

The top 4 most common causes for unintentional weight loss are cancer, gastrointestinal (digestive or stomach) disorders, mental health disorders, and unknown or unidentified causes.

  • Malignancy (cancer) - seen commonly with lung, gastrointestinal (digestive tract), pancreatic, lymphoma, kidney, and prostate cancer.
  • Gastrointestinal disease (non-cancer) - for example, Peptic Ulcer disease (PUD), malabsorption disorders (i.e., Celiac disease), Crohn’s disease or ulcerative colitis.
  • Mental health / psychiatric disorders - depression, eating disorders like anorexia nervosa or bulimia nervosa (altered food intake), or other psychiatric illnesses.
  • Electrolyte imbalances (high calcium, low sodium)
  • Certain medications (eg, digoxin, theophylline, SSRIs, antibiotics) or illicit drugs of abuse (see list below)
  • Dental / tooth problems
  • Drug or alcohol misuse, addiction
  • Endocrine disease - diabetes, especially type 1 diabetes, overactive thyroid (hyperthyroidism), Addison’s disease (adrenal glands don’t make enough cortisol, a natural hormone)
  • Infections - bacterial (eg, tuberculosis), viral (eg, HIV / AIDS, hepatitis), fungal (eg, Candidiasis) or parasitic (eg, tapeworm) infections
  • Chronic illness - congestive heart failure, lung disease (COPD), or kidney failure
  • Brain and nervous system disorders - Parkinson’s disease, Alzheimer’s disease / dementia, stroke (altered cognition), amyotrophic lateral sclerosis (ALS)
  • Vigorous exercise - common in long-distance running, ballet, gymnastics
  • Severe rheumatoid arthritis

Older adults can present with special problems leading to unintentional weight loss, which can include swallowing problems, depression, anxiety, inability to feed themselves (motor disorder) and tooth loss.

Social isolation can also further worsen depression or anxiety and complicate weight loss. In studies in nursing home patients, weight loss has been associated with depression in 36% of cases.

List of Drugs Associated with Weight Loss 

Prescription or over-the-counter (OTC) medications can be associated with weight loss. Your healthcare provider should do a thorough review of your medications if you have experienced recent unexplained weight loss.

Medicine or substance side effects such as altered taste or smell, stomach pain, dry mouth, or nausea / vomiting can often be responsible for loss of appetite and weight loss. Examples of common drugs known to cause weight loss include:

  • Alcohol
  • Caffeine
  • Cocaine, other illicit drugs
  • Amphetamines
  • Antidepressants (i.e., SSRIs, SNRIs)
  • Chemotherapy regimens (cancer treatments)
  • Tobacco / Nicotine
  • Anticonvulsant treatments
  • Diabetes drugs
  • Thyroid medicine
  • Some herbal supplements (5-hydroxytryptophan / 5-HT, aloe, cascara, chromium, dandelion, ephedra, garcinia, glucomannan, guarana, St. John's wort)
  • NSAIDs / aspirin
  • Clonidine
  • Allopurinol
  • Antiparkinson medicines
  • Opioids
  • Antibiotics
  • Diuretics
  • Vitamins; iron or potassium supplements.

What symptoms are associated with unintentional weight loss?

Eventually, if enough weight or muscle mass is lost, symptoms related to malnutrition may set in. Initially, symptoms associated with weight loss typically stem from the related medical conditions.

For example, symptoms such as pain, abdominal pain or distention, nausea, vomiting, trouble swallowing, and feeling full can be reported in patients with malignancies. Chemotherapy can result in chemo-induced nausea / vomiting.

Patients with gastrointestinal diseases such as inflammatory bowel disease or ulcer disease may report loss of appetite, stomach pain, trouble swallowing, diarrhea, constipation, or bleeding.

Patients with chronic hepatitis C virus may suffer from nausea, vomiting and loss of appetite.

Hyperthyroidism can be associated with an increased appetite, despite the ability to gain weight; however, older patients may present with loss of appetite and weight loss.

How is unintentional weight loss diagnosed?

There is no set guideline or diagnostic approach to patients with unintentional weight loss. In addition to a complete history, physical, and dietary assessment, your doctor may order laboratory testing or a psychiatric exam to help determine the cause of weight loss.

  • Diagnosis may include a battery of blood tests such as a complete blood count (CBC), calcium levels, thyroid-stimulating hormone level, kidney and liver tests, glucose (blood sugar) levels, C-reactive protein, and hepatitis C virus and HIV testing.
  • Other tests, such as a urinalysis, PSA (prostate) testing, stool testing, colonoscopy or a chest x-ray may be performed, if needed.
  • Your healthcare provider may assess your mental health to uncover signs of depression, anxiety, eating disorders, or other psychiatric conditions that may be contributing to any weight loss.

If a clear cause of weight loss is not identified, your healthcare provider may suggest a watchful waiting period of up to 6 months, with additional assessments as needed to evaluate your weight status and nutritional intake. Your doctor may also refer you to a dietician for meal planning.

Table 1. List of Treatments for Unintentional Weight Loss

Brand name Generic name  Drugs Class and Uses
None avaialble cyproheptadine Antihistamine H1 Antagonist (First generation)
  • Appetite, decreased secondary to chronic disease (off-label)
Marinol; Syndros  dronabinol Cannabinoid
  • Anorexia (appetite loss) associated with weight loss in patients with AIDS.
  • Nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatments.
Megace ES megestrol Progestin
  • Treatment of anorexia, cachexia, or an unexplained significant weight loss in patients with a diagnosis of acquired immunodeficiency syndrome (AIDS)
Serostim somatropin

Human growth hormone (hGH) analog

  • Treatment of HIV patients with wasting or cachexia to increase lean body mass and body weight, and improve physical endurance.

 

Drugs used to treat Weight Loss (Underweight)

The following list of medications are in some way related to or used in the treatment of this condition.

Filter
Drug name Rating Reviews Activity ? Rx/OTC Pregnancy CSA Alcohol
megestrol Off-label 8.3 28 reviews for megestrol to treat Weight Loss (Underweight)
Rx X N

Generic name: megestrol systemic

Drug class: hormones/antineoplastics, progestins

For consumers: dosage, interactions, side effects

For professionals: AHFS DI Monograph, Prescribing Information

Off-label: Yes

Frequently asked questions

Topics under Weight Loss (Underweight)

Legend

Rating For ratings, users were asked how effective they found the medicine while considering positive/adverse effects and ease of use (1 = not effective, 10 = most effective).
Activity Activity is based on recent site visitor activity relative to other medications in the list.
Rx Prescription only.
OTC Over-the-counter.
Rx/OTC Prescription or Over-the-counter.
Off-label This medication may not be approved by the FDA for the treatment of this condition.
EUA An Emergency Use Authorization (EUA) allows the FDA to authorize unapproved medical products or unapproved uses of approved medical products to be used in a declared public health emergency when there are no adequate, approved, and available alternatives.
Expanded Access Expanded Access is a potential pathway for a patient with a serious or immediately life-threatening disease or condition to gain access to an investigational medical product (drug, biologic, or medical device) for treatment outside of clinical trials when no comparable or satisfactory alternative therapy options are available.
Pregnancy Category
A Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).
B Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.
C Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use in pregnant women despite potential risks.
D There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use in pregnant women despite potential risks.
X Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use in pregnant women clearly outweigh potential benefits.
N FDA has not classified the drug.
Controlled Substances Act (CSA) Schedule
M The drug has multiple schedules. The schedule may depend on the exact dosage form or strength of the medication.
U CSA Schedule is unknown.
N Is not subject to the Controlled Substances Act.
1 Has a high potential for abuse. Has no currently accepted medical use in treatment in the United States. There is a lack of accepted safety for use under medical supervision.
2 Has a high potential for abuse. Has a currently accepted medical use in treatment in the United States or a currently accepted medical use with severe restrictions. Abuse may lead to severe psychological or physical dependence.
3 Has a potential for abuse less than those in schedules 1 and 2. Has a currently accepted medical use in treatment in the United States. Abuse may lead to moderate or low physical dependence or high psychological dependence.
4 Has a low potential for abuse relative to those in schedule 3. It has a currently accepted medical use in treatment in the United States. Abuse may lead to limited physical dependence or psychological dependence relative to those in schedule 3.
5 Has a low potential for abuse relative to those in schedule 4. Has a currently accepted medical use in treatment in the United States. Abuse may lead to limited physical dependence or psychological dependence relative to those in schedule 4.
Alcohol
X Interacts with Alcohol.

Further information

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