Long Acting vs Short Acting Insulin

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For patients with diabetes, certain types of insulin can help manage blood sugar levels and sustain overall health. Long-acting and short-acting insulins are two such categories prescribed for diabetes management. They each have different onsets, peaks, and durations but both aim to regulate glucose metabolism within the body. Long-acting insulin is designed to keep your blood sugar stable throughout an entire day with a relatively consistent level of insulin; it has no peak time because its purpose is to maintain a baseline level of insulin in your system. Short-acting or regular insulin, however, starts working within 30 minutes after injection, peaks between 2 to 3 hours later and keeps working for up to eight hours. Therefore, this type of Insulin is often used in conjunction with long-acting for controlling blood sugar at mealtimes.

What is Long Acting?

Long-acting insulin, such as Insulin Glargine (the generic name for Lantus), was a notable advancement from short-acting insulin like Regular Human Insulin. It is primarily used to control blood sugar levels throughout the day and night. Long-acting insulin was first approved by the FDA in 2000. Unlike short-acting insulin that provides rapid relief but must be administered more frequently, long-acting insulin mimics the slow, steady release of natural basal insulin produced by a healthy pancreas. This medication effectively maintains background glucose level over an extended period—typically up to 24 hours with just one injection per day—which results in it having fewer occurrences of hypoglycemia than other insulins that have stronger effects on rapidly lowering blood sugar levels.

What conditions is Long Acting approved to treat?

Long-acting and short-acting insulin are both approved for the treatment of different types of diabetes:

  • Type 1 diabetes: where the body's immune system destroys the cells that release insulin, eventually eliminating insulin production from the body.
  • Type 2 diabetes: a chronic condition that affects the way your body metabolizes sugar (glucose) — its main source of fuel.

Short acting insulins are often used to manage blood sugar levels during meals or snacks, or to correct very high blood sugar levels. Long acting insulins are usually taken twice daily to help control blood glucose in people with type 1 and type 2 diabetes.

How does Long Acting help with these illnesses?

Long-acting insulin helps to manage blood glucose levels by mimicking the baseline insulin production of a non-diabetic pancreas. It does this providing a slow, steady release of insulin over 24 hours, helping to maintain consistent glucose levels throughout the day and night. Insulin is a hormone that enables cells in the body to take in glucose from the bloodstream and use it as energy. Without sufficient insulin, excessive amounts of glucose can build up in the bloodstream leading to high blood sugar levels which can cause serious health complications if left untreated.

On the other hand, short-acting insulin works quickly by increasing available circulating insulin soon after injection but for a shorter duration typically around 3-6 hours depending on individual metabolism rates. This type is often used around meal times to control spikes in blood sugar caused by eating.

It's important for individuals with diabetes who require supplemental insulin therapy through injections or an insuline pump have both types available - long acting for basal coverage and short acting for bolus (mealtime) coverage - allowing them better control their condition and stabilize their blood sugar levels.

What is Short Acting Insulin?

Short-Acting Insulin, also known as Regular or Normal Insulin, works more quickly than long-acting insulin. It is typically taken just before meals to counteract the rise in blood sugar levels that occurs after eating. Short-acting insulin begins working within 30 minutes of injection and peaks at about 2 to 3 hours but can remain effective for up to six hours. This fast action allows for greater flexibility around meal times but does require more frequent injections than longer acting insulins.

Short-Acting Insulin was first approved by the FDA in the early years of insulin therapy and has been a mainstay in diabetes management ever since. Its primary role is to mimic the natural surge of insulin release in response to a meal, helping cells absorb glucose from food for energy and preventing hyperglycemia (high blood sugar levels). While it does require careful timing with meals and more injections throughout the day compared to other types of insulin, its quick onset can be particularly beneficial when rapid control over high blood sugars is needed.

What conditions is Short Acting Insulin approved to treat?

Short Acting Insulin is an essential treatment option for people with diabetes. It has been approved and widely used to manage the following:

  • Glycemic control in all types of diabetes.
  • To rapidly decrease high blood glucose levels, as it starts to work within 30 minutes after injection.
  • Flexibility around meal times because you can inject it just before eating or soon after finishing a meal.

How does Short Acting Insulin help with these illnesses?

Insulin is a hormone that plays a crucial role in many processes in the body, primarily regulating blood sugar levels and promoting the absorption of glucose from the bloodstream into cells. Short-acting insulin acts quickly to lower blood glucose levels, thereby providing relief for patients with high blood sugar. Its action onset typically begins within 30 minutes to an hour after injection, peaking at about 2 to 3 hours and lasting up to approximately 6–8 hours. This makes it particularly useful for managing blood sugar around meal times or during periods of unexpected high blood sugars. By contrast, long-acting insulin provides a steady baseline level of insulin over an extended period but does not offer immediate relief when blood sugars are suddenly elevated. While short-acting insulin doesn't replace long-term control provided by longer acting insulins, its ability to rapidly act on sudden spikes in blood sugar can be beneficial for diabetics who experience such fluctuations throughout their day.

How effective are both Long Acting and Short Acting Insulin?

Both long-acting insulin and short-acting insulin have crucial roles in diabetes management, despite being approved by the FDA at different times. Their unique characteristics allow them to be utilized for varying aspects of blood sugar control. Direct studies comparing their effectiveness reveal that both types are pivotal in managing blood glucose levels, albeit with differing durations and onset of action. No significant disparities were noted between patients receiving long-acting or short-acting insulin regarding hypoglycemic events.

A comprehensive review conducted in 2009 highlighted that long-acting insulins such as glargine (Lantus) or detemir (Levemir), can effectively maintain baseline blood glucose levels throughout the day when administered once daily. These insulins offer a consistent effect without pronounced peaks, making them ideal for basal coverage. Moreover, they provide flexibility due to their prolonged duration and reduced risk of nocturnal hypoglycemia compared to intermediate acting counterparts like NPH.

Short-acting insulins like lispro (Humalog), aspart (Novolog), and glulisine (Apidra) on the other hand offer rapid reduction of high post-meal blood sugars due to their quick onset and shorter duration of action - typically 3 to 5 hours. A meta-analysis carried out in 2016 confirmed these facts while also indicating that matching carbohydrate intake with appropriate doses can minimize risks associated with rapid-onset drugs like hypoglycaemia.

While both classes possess distinct advantages depending on individual needs; it's not uncommon for both types to be used together – a practice known as basal-bolus regimen, where long acting forms provide constant background coverage while short acting ones manage spikes caused by meals.

abstract image of a researcher studying a bottle of drug.

At what dose is Long Acting typically prescribed?

Dosages of insulin can vary greatly among individuals, but typically, long-acting insulin is used as a baseline treatment for maintaining blood sugar levels throughout the day and night. It's usually taken once or twice daily. Short-acting insulin, on the other hand, is often used to control spikes in blood sugar levels during meals. The dosage will depend on the carbohydrate content of the meal and can be adjusted based on individual response to treatment. In either case, starting doses are often determined by weight; an initial dose may be around 0.2 to 0.4 units/kg/day for long-acting insulin or 0.1 unit/kg/meal for short-acting insulin in adults and children alike. As with any medication regimen, it's essential that you closely monitor your blood glucose levels and consult with your healthcare provider regularly to determine if adjustments in your dosing are necessary.

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At what dose is Short Acting Insulin typically prescribed?

Short-acting insulin therapy typically begins with a dosage of 10 units/day or 0.2–0.4 units/kg/day, which could be divided into multiple doses before each meal. The dose can then be increased based on blood sugar levels and individual response to the treatment, usually spaced around mealtimes to control post-meal spikes in glucose levels. It's important not to exceed the prescribed maximum daily dose, as excessive use may lead to hypoglycemia (low blood sugar). If there is no satisfactory response to treatment after several weeks, your healthcare provider might consider adjusting your regimen or exploring additional therapeutic options.

What are the most common side effects for Long Acting?

Common side effects of long-acting insulin can include:

  • Hypoglycemia (low blood sugar)
  • Injection site reactions such as redness, swelling or itching
  • Weight gain
  • Swollen hands and feet

For short acting insulin, common side effects are similar but may also include:

  • Rapid heartbeat
  • Sweating
  • Anxiety
  • Blurred vision
  • Dizziness or drowsiness

Please note that this is not a comprehensive list. It's crucial to seek immediate medical attention if you experience severe symptoms such as trouble breathing, irregular heart rate, severe rash or other signs of allergic reaction after taking either type of insulin.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Long Acting?

While both long-acting and short-acting insulins play a crucial role in managing diabetes, they may have different side effects:

  • Hypoglycemia: This condition is characterized by low blood sugar levels that can lead to feelings of lightheadedness, confusion, slurred speech or even fainting. Hypoglycemia can occur acutely with short-acting insulin if food intake isn't properly balanced with the dose.

  • Allergic reactions: Although rare, some people may experience an allergic response to either type of insulin. Symptoms could include swelling of your face or throat, difficulty breathing, skin rashes or hives.

  • Changes in vision: Rapid changes in blood glucose levels associated particularly with short acting insulin might cause temporary blurred vision.

  • Lipodystrophy: Repeated injections at the same site can cause this condition where fat builds up under the skin causing lumps. This is more common with long-term use of any type of injectable insulin.

If you notice these symptoms after taking either form of insulin it's essential to seek medical attention immediately.

What are the most common side effects for Short Acting Insulin?

Short-acting insulin can cause the following side effects:

  • Hypoglycemia (low blood sugar)
  • Hunger
  • Sweating and trembling
  • Rapid heartbeat
  • Confusion, irritability or mood changes
  • Fatigue or weakness
  • Blurred vision
  • Headache -Nausea, vomiting, abdominal discomfort
    -Injection site reactions such as redness, swelling or itching.

Remember that tight control of your blood glucose levels can help reduce the risk of long-term complications from diabetes. Always monitor your blood glucose levels closely after taking short acting insulin to ensure they do not drop too low.

Are there any potential serious side effects for Short Acting Insulin?

Short-acting insulin can sometimes cause serious side effects. Be vigilant for any of the following symptoms:

  • Signs of an allergic reaction, such as hives, itching, difficulty breathing or swallowing
  • Swelling in your face or throat
  • Changes in behavior or mood swings
  • Blurred vision and/or changes in eyesight
  • Rapid heartbeat or palpitations
  • Severe hypoglycemia characterized by sweating excessively, feeling extremely weak or shaky, confusion, fast heartbeat and even seizures

These symptoms could possibly indicate a severe reaction to short acting insulin. If you experience any of these symptoms after taking short acting insulin, contact your healthcare provider immediately.

Contraindications for Long Acting and Short Acting Insulin?

Both long-acting and short-acting insulin, like most other diabetic medications, may cause a drop in blood sugar levels if not managed correctly. If you notice symptoms of hypoglycemia such as dizziness, confusion, or sweating excessively please seek immediate medical help.

Neither long-acting nor short-acting insulin should be used if you are taking certain drugs that affect your body's response to insulin. Always tell your physician about all the medications you are taking; some medicines may need to be stopped or doses adjusted to prevent dangerous interactions with both types of insulin.

Remember that switching from one type of insulin to another is not simple and should always be done under a healthcare provider’s supervision. The effect of changing the dose timings can vary greatly between individuals due to different lifestyle habits and metabolic rates.

How much do Long Acting and Short Acting Insulin cost?

For the brand name versions of these drugs:

  • The price for a vial (10 mL) of long-acting insulin, such as Lantus or Levemir, averages around $300 to $400. Daily costs depend largely on your dose but can range from about $3 to $20/day.
  • The price for short-acting insulin, like Novolog or Humalog, is comparable at approximately $275-$350 per vial (10 ml). Again daily costs will vary based on dosage and could range between $2.50 to over $15/day.

Thus, if you require higher doses of insulin each day then it's possible that short-acting brands may be less expensive on a per-day treatment basis. However cost should not be your primary consideration in determining which type of insulin is right for you.

When looking into generic versions - also known as "biosimilars" in the case of insulins - there are some options:

  • A biosimilar version of long acting-insulin glargine (Lantus), called Basaglar by Eli Lilly and Company comes with a smaller price tag: around $235-$280 per pen containing 3ml.

  • Admelog is a biosimilar version of fast acting Insulin Lispro (Humalog) priced between 150$ to 200$/5x3ml pens.

Prices can vary greatly depending upon insurance coverage and pharmacy markups so always check prices before purchasing.

Popularity of Long Acting and Short Acting Insulin

Long-acting insulin, such as glargine (Lantus) and detemir (Levemir), was estimated to have been prescribed to about 7.8 million people in the US in 2020. Long-acting insulin accounted for just over 40% of all types of insulin prescriptions in the US. It is primarily used to keep blood sugar levels stable throughout the day and night.

On the other hand, short-acting or regular insulin like Humulin R and Novolin R was prescribed to approximately 6.1 million individuals in the USA during that same year. This type of insulin accounts for nearly a quarter of all types of insulin given out within this time frame, with its primary function being designed to cover blood sugar elevations from eating food, often administered shortly before meals due to its rapid onset.

The usage numbers between these two forms appear somewhat stable over recent years but it's important patients work closely with their healthcare providers since both are critical components within an overall diabetes management plan depending on individual needs.


Both long-acting and short-acting insulin are used to manage glucose levels in patients with diabetes. Numerous clinical studies have demonstrated their effectiveness in controlling blood sugar, although they serve different roles based on their duration of action.

Short-acting insulin is typically used during meals to control spikes in blood glucose that occur after eating, while long-acting insulins provide stable coverage for a full 24 hours or longer, managing the baseline level of blood sugar.

The use of both types might be combined for comprehensive control over the patient's glycemic state but must be carefully managed by a healthcare provider due to potential risks associated with incorrect dosing or timing. Short-acting insulin is generally administered at meal times while long acting insulin is usually given once daily at bedtime.

Both forms come in generic versions which can mean significant cost savings especially for those paying out-of-pocket. Both may require an adjustment period as it takes time to fine-tune dosage and timing according to individual needs.

As far as side effects go, both kinds carry similar risks such as hypoglycemia (low blood sugar), weight gain and injection site reactions like redness or swelling. However, these are generally manageable if caught early and discussed with your doctor promptly.

For both types of insulin, patients must monitor their blood glucose regularly particularly when initiating treatment or changing doses – immediate medical help should be sought if there are signs suggestive of severe hypoglycemia such as confusion, unconsciousness or seizures.