Byetta (Exenatide Synthetic)
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What is Byetta (exenatide)?

Byetta (exenatide) is brand-name injectable medication that is classified as an antidiabetic drug. It is used to treat symptoms associated with type 2 diabetes mellitus.

It contains exenatide that is considered an incretin mimetic. Incretins, such as human-glucagon-like peptide-1 (GLP-1) are hormones produced and released into the blood by the intestine after meals.

Studies have shown that GLP-1 reduces appetite and helps patients with weight loss.

Diet and exercise are usually recommended as part of treatment in order to improve glycemic control.

Byetta is currently not approved or considered safe for children.


Byetta is available as a prefilled pen that is injected subcutaneously (under the skin). Doses are typically taken before major meals during the day (i.e. breakfast and dinner).

It is typically prescribed by on its own or with other diabetes medications such as metformin, a sulfonylurea, or both to help lower your blood glucose levels.

Byetta has shown to significantly lower hemoglobin A1c (HbA1c) which measures average blood sugar levels over a period of 2-3 months.

In clinical studies where people received Byetta on its own for a period of 24 weeks found a reduction in their HbA1c levels by 0.7% to 0.9%. Adversely, patients receiving a placebo saw a 0.2% reduction. Those receiving Byetta also experienced a reduction in their average fasting blood glucose levels by 17-19 mg/dL. Those receiving the placebo experienced a reduction of 5 mg/dL.

In other studies that included other antidiabetic medications.

How is Byetta Used?

Before using Byetta, patients should read the Pen Manual and Medication Guide. Review medication preparation and usage instructions with your pharmacist. If you have any questions regarding this medication or why you are taking it, consult your doctor or pharmacist.

Inspect your medication for any discoloration or particles. If either are visible do not use.

Prior to injection clean the area with a cotton swab and rubbing alcohol. Rotate the injection site to avoid any skin complications.

Byetta should be injected twice per day in the upper thigh, upper arm or abdomen as instructed by your doctor, nurse or diabetes practitioner.

It is recommended to administer medication 1 hour before meals (not after meals as it may not work as well), at least 6 hours apart and before the two main meals of the day. .

If you are also using insulin, separate your injections and do not mix them together. Avoid injecting both medications into the same spot.

Consult your doctor about any medications, over-the-counter-drugs or supplements you are taking so they can create a regimen for your drugs to avoid interactions.

Your dosage of Byetta is based on your existing medical condition and how your body responds to the treatment. Try to schedule your injections at the same time every day and follow your doctors diabetes treatment plan, diet and exercise recommendations if provided. Set reminders for injections in your smartphone to avoid missing doses.

Monitor your blood glucose levels regularly or as instructed by your doctor. Keep your doctor informed on your blood monitoring results. Your doctor may choose to adjust your treatment based on your blood sugar level results.

The typical starting dose for Byetta is 5 µg (micrograms) and maximum dose is 10 µg twice daily.

How to store Byetta

Before first use:

  • Byetta should be stored in the refrigerator before first use.
  • Store away from direct light and do not allow medication to freeze.
  • Keep away from children and pets.

After first use:

  • Store this medication at room temperature
  • Discard medication that is still in the pen after 30 days
  • Do not store with needle attached to avoid leakage

Do not dispose of medication in household trash or down waste water (i.e. down sink or toilet). Speak to your pharmacist about how to properly dispose of medication that is expired or no longer needed.

Patients should read the medication guide an pen user manual prior to starting their treatment with Byetta. Patients should receive instructions on proper use, storage and proper setup.

Pen needles are not included with the pen and must be purchased separately. Pharmacists should advise the correct needle length and gauge to be used.


Do not share your pen with others, even if the needle has been changed as this can lead to spreading infections or blood-borne pathogens.

Do not inject this medication if it contains particles; appears colored or cloudy.

If you skip a dose or miss a dose, continue with your regular dosing schedule. Never take a double dose if you have missed one.

Inform your doctor if you have any allergies, especially to exenatide. This product may contain inactive ingredients that may cause allergic reactions. Speak to your doctor or pharmacist about what to do if you have an allergic reaction.

Inform your doctor if you have any significant issues with your health or medical history such as kidney disease, stomach/intestinal disorders (such as digestion problems, gastroparesis), disease of the pancreas (pancreatitis), certain blood disorder from exenatide (drug-induced thrombocytopenia) or stones in your gallbladder (gallstones).

Some patients may experience symptoms such as dizziness or drowsiness, headache, blurred vision which maybe the result of extremely low or high blood sugar. Do not drive or operate heavy machinery unless it’s clear you can do so safely..

Since alcohol may lead to low blood sugar levels, limit alcohol usage.

Fever, stress, injury, surgery or infection can affect blood sugar levels. Inform your doctor if you experience any of these as it may require closely monitoring glycemic levels and adjusting treatment.

Inform your doctor of other prescription medications, over-the-counter drugs or herbal supplements you are currently taking.


This medication should only be used if necessary during pregnancy. Speak to your doctor about managing blood sugar while you are pregnant. Your doctor may modify your treatment, such as diet and medications, since pregnancy can cause or worsen diabetes. Inform your doctor if you are pregnant or planning on becoming pregnant.


Whether medication travels through breast milk is currently unknown and unlikely to harm an infant. Consult your doctor if you plan on breastfeeding. In animal studies, exenatide was present in breast milk of lactating mice however this is not conclusive with humans.

Acute Pancreatitis

Byetta has been associated with fatal and non-fatal acute pancreatitis. Be aware of symptoms such as severe stomach pain or vomiting. If pancreatitis is suspect your doctor immediately discontinue Byetta and choose alter treatment.


The risk of hypoglycemia may increase if Byetta is used in combination with other medications such as metformin or sulfonylurea. Your doctor may choose to adjust dosage of other medications such as sulfonylurea to avoid the risk of hypoglycemia.

The dose of insulin should be evaluated if used together with Byetta.

Acute Kidney Injury

Some reports have shown altered renal function including renal impairment, increased serum creatinine, acute renal failure, sometimes requiring hemodialysis or kidney transplantation. Diarrhea, vomiting and nausea are symptoms that have occurred in some patients. Byetta is not suggested for patients who have severe renal impairment.

Gastrointestinal Disease

Byetta has not been studied and is not recommended with patients with serious gastrointestinal disease including gastroparesis. This is due to side effects users may experience such as diarrhea, nausea and vomiting.


Some patients treated with Byetta have experienced serious hypersensitivity (i.e. angioedema and anaphylaxis). If patients experience these reactions they must discontinue use and consult their doctor.

Drug-Induced Thrombocytopenia

Serious bleeding from drug-induced immune-mediated thrombocytopenia has been reported, which can be fatal. Drug-induced thrombocytopenia is an immune-mediated reaction with exenatide-dependent anti-platelet antibodies. If this occurs, treatment with Byetta should be discontinued.


The safety and effectiveness of using Byetta has not been established in children and adolescents under the age of 18.


Seniors may be more sensitive to this medication and likely to experience side effects.

Heart Problems

Byetta may increase your heart rate and how electrical impulses travel through the heart. If you currently have heart complications such as angina, a recent heart attack, heart failure or abnormal heart rhythm (i.e. rapid heart rate or heart block) inform your doctor immediately to see what may be required for management, if special monitoring is required or if any modifications need to be made to your treatment.

Byetta Drug Interactions

What drugs may interfere with Byetta?

  • acetaminophen
  • antiarrhythmics (i.e. amiodarone, sotalol, )
  • beta-blockers (i.e. metoprolol, atenolol)
  • buserelin
  • calcium channel blockers (i.e. diltiazem, verapamil)
  • combination oral contraceptives (birth control pills)
  • danazol
  • digoxin
  • diuretics (i.e. furosemide, hydrochlorothiazide, spironolactone; water pills)
  • epinephrine
  • goserelin
  • inhaled corticosteroids (i.e. budesonide, ciclesonide, fluticasone)
  • insulin
  • lisinopril
  • leuprolide
  • lovastatin
  • nandrolone
  • nasal decongestants (i.e. phenylpropanolamine, pseudoephedrine)
  • oral corticosteroids (i.e. dexamethasone, hydrocortisone, prednisone)
  • pegvisomant
  • protease inhibitors (i.e. indinavir, ritonavir, saquinavir)
  • somatropin
  • sulfonylureas (i.e. gliclazide, glyburide)
  • testosterone
  • warfarin

Inform your doctor or pharmacist if you are taking any of these medications. Your doctor may decide to make the following changes depending on your circumstances.

  • replace on medication to another
  • discontinue using one of the medications
  • adjust your medication schedule or dosage
  • leave everything as is.

Interactions do not always occur however if they do, continue your treatment as usual and speak to your doctor about how to manage your treatment or drug interactions.

Inform your doctor if you are taking any additional medications, over-the-counter drugs, vitamins or supplements. This should also include caffeine, nicotine, alcohol and street drugs as they may also interact with your treatment.


As with most medications, Byetta can have side effects that can range from mild to severe.

The following information below consists of side effects that may occur however does not include all possible side effects.

Speak to your doctor or pharmacist about the possible side effects and best practices to manage them if they become bothersome.

Common Side Effects with Byetta can include:

  • constipation
  • diarrhea
  • dizziness
  • feeling jittery
  • headaches
  • indigestion
  • nausea
  • reduced appetite
  • vomiting
  • hypoglycemia (low blood sugar)

Mild side effects can be managed and typically go away within a few days or weeks. Speak to your doctor if they do not go away or become bothersome.

Serious side effects can include:

Acute pancreatitis (inflammation of the pancreas). Symptoms include:

  • nausea
  • severe abdominal pain
  • back pain
  • vomiting

Problems with kidney function (including kidney failure). Symptoms can include

  • confusion
  • swollen feet or ankles
  • fatigue (lack of energy)
  • urinating less than usual

Low platelet level. Symptoms can include:

  • purple spots or bruising of the skin
  • tiredness
  • blood in urine
  • heavy or long lasting bleeding

Severe allergic reactions.

Serious side effects aren’t common but can occur. Contact your doctor immediately if you are experiencing any severe side effects or call 911 for medical emergency if you feel they are life threatening.

Side Effect Details

The following information below details side effects related to Byetta in greater detail.

Allergic Reaction

Some people may allergic to some of the ingredients contained in Byetta. Mild allergy symptoms can include:

  • skin rash
  • itchiness
  • flushing (redness & warmth of skin)

Although rare, severe allergic reactions are possible. Symptoms can include:

  • chest tightness
  • skin swelling, typically in the lips, eyelids, hands and feet
  • swelling of the mouth, tongue or throat
  • difficulty breathing

Contact your doctor if symptoms from a severe allergic reaction do not go away. If you feel symptoms are life-threatening, call 911 for immediate medical emergency.

During clinical studies, allergic reactions were not reported. However, since the market has been introduced to the market in 2005, mild to severe allergy symptoms have been reported. It is unclear how often allergic reactions occur.


While taking Byetta, patients may experience a drop in blood sugar levels. This is referred to as hypoglycemia (or hypo for short). This occurrence is more likely if you are taking other drugs with Byetta, specifically insulin and sulfonylurea drugs such as gliclazide.

5.2% of people using Byetta experienced hypoglycemia during a clinical trial. Subjects were given 5mcg of Byetta twice daily for the 24-week trial. Of those given the placebo (not an active drug), hypoglycemia occurred in 1.3% of them.

In a 30-week clinical study, 4.5% of the group given 5mg of Byetta twice daily with metformin (a drug that helps lower blood sugar) experienced hypoglycemia. In comparison, 5.3% of the placebo group experienced hypoglycemia.

In a 30-week clinical study, 14.4% of people given 5mcg of Byetta twice daily with sulfonylurea (which helps lower blood sugar) experienced hypoglycemia. In comparison, 3.3% of those who received the placebo experienced hypoglycemia.

Symptoms of hypoglycemia can include:

  • anxiety
  • blurred vision
  • confusion
  • dizziness
  • fast heartbeat
  • feeling jittery or shaky
  • feeling weak or tired
  • headache
  • hunger
  • pale skin
  • sudden mood changes
  • sweating
  • trouble concentrating

Pancreatitis (inflammation of the pancreas) – this wasn’t experienced by anyone in clinical trials but there have been a few reported cases, some serious or fatal, since the drug was released into the market in 2005. If you experience any symptoms of acute pancreatitis contact your doctor or seek medical attention immediately.

Symptoms of pancreatitis can include:

  • fever
  • nausea
  • swollen or bloated belly
  • severe stomach pain that may spread to your back and won’t go away
  • vomiting
  • weight gain or weight loss

Speak with your doctor about what to do if you experience symptoms of hypoglycemia.

Weight Gain

Patients using Byetta are unlikely to gain weight however may lose weight since it reduces appetite.

In a 24-week clinical study, people using Byetta only lose an average of 6.-6.4 pounds. In comparison, those taking a placebo only lost 3.3 pounds over the same time period.

In a 30-week clinical study, those who used Byetta with metaformin lost 2.9-5.7 pounds compared to those who were receiving a placebo who lost an average of 0.4 pounds.

In a 30-week clinical study, patients who were given Byetta with sulfonylurea lost 2.4-3.5 pounds compared to those who received the placebo who lost an average of 1.8 pounds.

Beytta is not a weight loss and shouldn’t be taken for that purpose however 1-2% of people have reported a loss of appetite.


Some patients have experienced nausea when first starting Byetta which why most people start with a low dose.

In clinical studies:

  • 8% of those using only Byetta experienced nausea and 4% experienced vomiting. The placebo group did not experience neither.
  • 44% experienced nausea and 13% experienced vomiting who were on a combination of Byetta and metformin, a sulfonylurea or both. 18% experienced nausea and 4% vomiting of the placebo group.

These symptoms tend to go away over time. Speak to your doctor if feeling of nausea and vomiting are still being experienced after a few weeks, especially since these can also be symptoms of acute pancreatitis.

Hair Loss

Hair Loss has been reported after Byetta was approved however in clinical studies it was not reported. Speak to your doctor if you are concerned about hair loss prior to treatment with Byetta.


Diarrhea was experienced by some people using Byetta. In clinical studies where subjects were using only Byetta, 1-2% reported diarrhea. 13% of people using Byetta along with metformin, a sulfonylurea or both experienced diarrhea.

Consult your doctor or pharmacist if you experience diarrhea while using Byetta so they can provide ways to better manage it. To avoid getting dehydrated, drink plenty of fluids. If diarrhea is severe and not going away inform your doctor.