Insulin Human Regular (Injection)


Insulin is a hormone which is naturally produced by the pancreas. It is the main anabolic hormone in the body and is responsible for the regulation of the metabolism of fats, carbohydrates and protein. It achieves this by absorbing glucose from the bloodstream into liver, fat and skeletal muscle cells. From here, the absorbed tissues are converted into fats (via lipogenesis) or glycogen (via glycogenesis), or both. Insulin in the blood inhibits the production and secretion of glucose by the liver.

When the pancreas fails to produce any insulin, the patient develops a condition known as type 1 diabetes. The symptoms of this condition can develop incredibly quickly in younger patients (over days or weeks). In adults and older patients, symptoms of type 1 diabetes typically take a little longer to develop (usually a few months).

The most common symptoms associated with lack of insulin/type 1 diabetes include:

  • An increased feeling of thirst
  • Passing more urine than normal, particularly at night time
  • Feeling unusually tired or lethargic
  • Weight loss
  • Loss of muscle mass

These symptoms occur because the lack of insulin means glucose stays present in the blood, instead of being used as fuel to create energy. The body attempts to lower blood glucose levels by excreting excess glucose via the urine.

To treat type 1 diabetes, the patient will generally require regular injections of insulin, which is often marketed as insulin human regular. In some states, it may be branded as HumuLIN. It is supplied as a short-acting form of the hormone designed to alleviate type 1 diabetes.

Insulin can also be used off-label to treat other conditions, at the discretion of the prescribing doctor.

Type Of Medicine

  • Hormone

Conditions Treated

  • Type 1 diabetes

Side Effects

Like most medicines, insulin can cause some unwanted side effects along with its desired effects. The most common side effects reported by patients undergoing regular treatment with insulin human regular include the following:

  • Chills
  • Changes in eyesight
  • Severe dizziness, to the point of passing out
  • Changes in mood
  • Seizures
  • Slurred speech
  • Irritation at the site of injection
  • Changes in skin at the site of injection
  • Abnormal heartbeat
  • Abnormal numbness, tingling or burning
  • Low potassium levels (signs can include muscle cramps, weakness, and changes in the heartbeat)

In some cases, insulin can cause signs and symptoms of an allergic reaction. Although it may be rare, some people react badly to this medication and may experience the following side effects in varying severities:

  • Rash
  • Itching
  • Red, swollen, blistered or peeling skin
  • Fever
  • Tightness in the chest
  • Tightness in the throat
  • Swelling of the mouth, lips, face, tongue or throat
  • Wheezing

Typically, most patients only experience very minimal side effects when taking insulin injections - if they observe any side effects whatsoever. Over time, the drug can actually alleviate many of the previously mentioned side effects, and healthcare professionals agree that the benefits of controlling type 1 diabetes far outweigh the risks of experiencing temporary mild discomfort.

As the patient continues to take insulin human regular (HumuLIN) as prescribed by a qualified physician, most (if not all) of the previously mentioned symptoms should begin to lessen. If side effects persist for a prolonged period or appear to get worse, the patient is advised to inform their doctor as soon as possible. In many instances, a doctor or pharmacist may be able to recommend over the counter treatments or other prescription medicines to help alleviate any side effects that are causing particular discomfort.

It is worth noting that injected insulin can affect the co-ordination of the patient, causing symptoms like dizziness, seizures and loss of consciousness in rare circumstances. Because of this, patients are advised to refrain from driving or operating heavy machinery after injecting insulin, until it has been observed that these side effects do not have any detrimental effect on the patient's ability to concentrate. This is because the patient could otherwise put themselves or other road users at risk of injury or even death.

Not all side effects may have been reported or listed. If a patient thinks they may have experienced an unreported side effect, they are advised to consult their doctor and report their findings to the FDA.


As with all medicines, it is imperative that the patient only takes insulin as prescribed by a qualified physician. This means that patients must avoid taking any more of the drug than they have been advised to, either in terms of dose size or frequency. In addition to this, patients should be prepared to stop taking insulin when advised to do so by their doctor, even if they still have a supply of the drug remaining.

Patients are advised to follow all of the instructions printed on their insulin prescription label, and to familiarize themselves with the process of injecting insulin, under the supervision of a doctor or healthcare professional, who should be available to advise the patient on how to administer injections at home.

Regular human insulin is injected under the skin. The patient should choose a different site for injection each time they administer this medicine - it is important not to inject into the same area twice in a row.

Disposable needles should be used only once, and discarded into a safe, hygenic, purpose-built puncture-proof container (most doctors or pharmacists will be able to advise on where to get a "sharps"container, and how to safely dispose of them). Sharps containers should be kept out of the reach of children and/or pets.

When administering a dose of insulin, patients should take great care not to use a cartridge or pen which has previously been used by another person. Sharing pens, cartridges or needles can allow for the spread of dangerous infectious diseases such as HIV or hepatitis.

Typical adult dose for type 1 diabetes:

Regular human insulin (HumuLIN) is available in two standard concentrations - a small, short-acting dose (100 units of insulin per mL) and a larger, longer-acting dose (500 units of insulin per mL).

Individual doses should be based on the metabolic needs of the patient, which can be determined by frequently monitoring blood glucose levels. Most patients will typically require insulin at a rate of between 0.5 to 1 unit per kg per day, which can be administered via multiple daily injections of a continuous, sub-cutaneous infusion of insulin (sometimes referred to as a CSII).

Patients who utilize a combination of short and long-acting insulin injections may require three to four injections of the drug per day, based on their individual condition and blood glucose levels. Glucose levels are variable dependent on diet and other external factors.

Short-acting insulin (U-100) should be administered at least three times a day, approximately 30 minutes before eating a meal. Long-acting (U-500) insulin should be administered no more than three times per day, approximately 30 minutes before eating a mean.

During intravenous administration of short-acting (U-100) insulin, blood glucose and serum potassium should be closely monitored.

Insulin pump therapy (CSII) is compatible with short-acting (U-100) insulin only. Initial programming of the pump should ideally be based on the standard daily insulin dose of the patient's previous injection regimen. Prior to pump use, the patient and/or their doctor should check to ensure that the equipment has been tested for use with the specific brand of insulin the patient is receiving (for example, certain brands of insulin, such as Novolin, are not recommended for use within an insulin pump on account of a risk of precipitation).

Sometimes, interpatient variability may occur. In these instances, approximately 50 per cent of the standard daily dose should be provided as meal-related injections, with the remainder administered via pump as an infusion.

Injecting insulin:

Before self-administering insulin, the patient must fill the correct syringe with the correct amount of medication, before following these guidelines:

  • Wash hands with soap and water, before drying them well.
  • Inspect the label on the bottle of insulin, to ensure it is the correct type of medicine and has not expired.
  • Insulin should not have any clumps on the inside of the bottle. If it does, it should be discarded and the patient should use another bottle.
  • Intermediate or long-acting insulin can be cloudy, and the bottle should be rolled between the hands to mix it. Short-acting, clear insulin does not require mixing.
  • The needle should be pushed through the rubber cap on the insulin bottle, with the blunger pushed so that air enters the bottle.
  • The needle should be kept in the bottle as it is turned upside-down.
  • With the needle tip in the liquid, the patient should pull back on the plunger to allow insulin to enter the syringe.
  • Syringe must then be checked for bubbles. If bubbles are present, the bottle and syringe should be held in one hand while the syringe is tapped with the other hand. This will cause bubbles to float to the top. Bubbles should be pushed back into the insulin bottle via the plunger, which should then be pulled back again to collect the correct dose.
  • Patient should now be ready to administer the insulin, ensuring they are not injecting in an area which has recently been injected. Injections should be kept at least 1 inch away from scars, and 2 inches away from the navel area.
  • Patient should pinch skin of the injection site and insert the needle at a 45-degree angle.
  • The needle should be pushed all the way into the skin before the patient lets go of the pinched skin.
  • Plunger should be depressed slowly and steadily, ensuring all insulin enters the body.
  • Syringe should be left in place for at least five seconds after injection.
  • Syringe should be removed and placed in a safe "sharps"container.

While the manufacturer of human regular insulin provides general dosage instructions, it must be reiterated that these are merely guidelines which can be adjusted at the discretion of the prescribing doctor. Factors discussed between the patient and doctor will help to determine standard dose sizes, along with data collected via blood tests and other metrics. The age, height, weight and condition of the patient also plays a role when determining optimum insulin dose levels.

Patients are advised against taking double doses. If he or she misses a dose, they should take the dose as soon as they realize. In most instances the patient will experience symptoms that should inform them a dose is required (sleepiness and increased urination), allowing them to self-correct. However, taking more insulin than advised is not recommended, as this can lead to overdose. Patients who experience signs of overdose (loss of consciousness, changes in heartbeat, seizures) may require immediate medical attention, and should contact their local poison control center on 1800-222-1222 or emergency services on 911 without hesitation or delay, as their condition could potentially be life-threatening.


All medicines have the potential to interact with other drugs or medicines within the human body. These interactions can change how one or more medications work, rendering them ineffective in treating the condition they were prescribed to combat. In some instances, interactions can even cause dangerous and potentially fatal side effects. Because these risks exist, patients are advised to keep a full, detailed account of all medications they are currently taking. This extends to over the counter remedies, vitamins, herbal supplements and complimentary medicines as well as prescribed drugs.

The following is a list of medicines known to interact with regular human insulin. Patients who are currently undergoing treatment with one or more of these medications should inform their doctor prior to beginning treatment with insulin:

  •  Metformin/Sitagliptin
  •  Metformin/Saxagliptin
  •  Metformin/Rosiglitazone
  •  Metformin/Repaglinide
  •  Metformin/Pioglitazone
  •  Metformin
  •  Metaraminol
  •  Metaproterenol
  •  Mestranol/Norethindrone
  •  Mesoridazine
  •  Mephentermine
  •  Meperidine/Promethazine
  •  Megestrol
  •  Medroxyprogesterone
  •  Mecasermin Rinfabate
  •  Mecasermin
  •  Mazindol
  •  Magnesium Salicylate/Phenyltoloxamine
  •  Magnesium Salicylate
  •  Ma Huang
  •  Linezolid
  •  Linagliptin/Metformin
  •  Linagliptin
  •  Lidocaine/Oxytetracycline· Levothyroxine
  •  Levonorgestrel
  •  Levofloxacin
  •  Levobunolol Ophthalmic
  •  Levobetaxolol Ophthalmic
  •  Leuprolide/Norethindrone
  •  Leuprolide
  •  Lanreotide
  •  Labetalol
  •  Insulin Glargine/Lixisenatide
  •  Insulin Degludec/Liraglutide
  •  Indinavir
  •  Indapamide
  •  Indacaterol· Iloperidone
  •  Ibuprofen/Pseudoephedrine
  •  Ibuprofen/Phenylephrine
  •  Hydrochlorothiazide/Triamterene· Hydrochlorothiazide/Timolol
  •  Hydrochlorothiazide/Telmisartan· Hydrochlorothiazide/Spironolactone· Hydrochlorothiazide/Reserpine
  •  Hydrochlorothiazide/Quinapril
  •  Hydrochlorothiazide/Propranolol
  •  Hydrochlorothiazide/Olmesartan
  •  Hydrochlorothiazide/Moexipril
  •  Hydrochlorothiazide/Metoprolol
  •  Hydrochlorothiazide/Methyldopa
  •  Hydrochlorothiazide/Losartan
  •  Hydrochlorothiazide/Lisinopril· Hydrochlorothiazide/Irbesartan
  •  Hydrochlorothiazide
  •  Guaifenesin/Hydrocodone/Pheniramine/Phenylephrine/Phenylpropanolamine
  •  Grepafloxacin
  •  Goserelin
  •  Glycopyrrolate/Indacaterol
  •  Glyburide/Metformin
  •  Glipizide/Metformin
  •  Glimepiride/Rosiglitazone
  •  Glimepiride/Pioglitazone
  •  Ginseng
  •  Gemifloxacin
  •  Gemfibrozil
  •  Fluticasone/Salmeterol
  •  Fluphenazine
  •  Fluoxymesterone
  •  Fluoxetine/Olanzapine· Fluoxetine· Fludrocortisone
  •  Fludeoxyglucose F18
  •  Fexofenadine/Pseudoephedrine· Fenofibric Acid
  •  Fenofibrate
  •  Fenfluramine
  •  Ephedrine/Phenobarbital/Potassium Iodide/Theophylline
  •  Ephedrine/Hydroxyzine/Theophylline
  •  Ephedrine/Guaifenesin/Theophylline
  •  Ephedrine/Guaifenesin
  •  Ephedrine
  •  Enoxacin
  •  Enalapril/Hydrochlorothiazide
  •  Enalapril/Felodipine· Emtricitabine/Nelfinavir/Tenofovir
  •  Emtricitabine/Lopinavir/Ritonavir/Tenofovir
  •  Empagliflozin/Metformin
  •  Empagliflozin/Linagliptin
  •  Empagliflozin
  •  Dexbrompheniramine/Dextromethorphan/Phenylephrine/Pyrilamine
  •  Dexbrompheniramine/Dextromethorphan/Phenylephrine
  •  Dexamethasone/Lidocaine
  •  Dexamethasone
  •  Desogestrel/Ethinyl Estradiol
  •  Desloratadine/Pseudoephedrine
  •  Deserpidine/Methyclothiazide
  •  Deserpidine/Hydrochlorothiazide
  •  Deserpidine
  •  Demeclocycline
  •  Delafloxacin
  •  Deflazacort
  •  Dasabuvir/Ombitasvir/Paritaprevir/Ritonavir
  •  Darunavir
  •  Dapagliflozin/Saxagliptin
  •  Dapagliflozin/Metformin
  •  Dapagliflozin
  •  Danazol
  •  Dabrafenib
  •  Carbinoxamine/Pseudoephedrine
  •  Carbinoxamine/Phenylephrine
  •  Carbinoxamine/Methscopolamine/Pseudoephedrine
  •  Carbinoxamine/Hydrocodone/Pseudoephedrine
  •  Carbinoxamine/Hydrocodone/Phenylephrine
  •  Carbinoxamine/Dextromethorphan/Pseudoephedrine· Carbinoxamine/Dextromethorphan/Phenylephrine
  •  Carbetapentane/Pseudoephedrine/Pyrilamine
  •  Carbetapentane/Pseudoephedrine
  •  Carbetapentane/Phenylephrine/Pyrilamine
  •  Carbetapentane/Phenylephrine/Potassium Guaiacolsulfonate·
  • Carbetapentane/Phenylephrine/Phenylpropanolamine/Potassium · Guaiacolsulfonate
  •  Carbetapentane/Phenylephrine
  •  Carbetapentane/Guaifenesin/Pseudoephedrine
  •  Carbetapentane/Guaifenesin/Phenylephrine
  •  Carbetapentane/Diphenhydramine/Phenylephrine·
  • Carbetapentane/Dexchlorpheniramine/Phenylephrine
  •  Carbetapentane/Chlorpheniramine/Phenylephrine
  •  Carbetapentane/Chlorpheniramine/Ephedrine/Phenylephrine
  •  Carbetapentane/Carbinoxamine/Phenylephrine
  •  Caramiphen/Phenylpropanolamine
  •  Captopril/Hydrochlorothiazide
  •  Captopril
  •  Candesartan/Hydrochlorothiazide· Candesartan
  •  Canagliflozin/Metformin
  •  Canagliflozin
  •  Caffeine/Pheniramine/Phenylephrine/Sodium Citrate/Sodium Salicylate
  •  Caffeine/Magnesium Salicylate
  •  Brompheniramine/Chlorpheniramine
  •  Brompheniramine/Chlophedianol/Pseudoephedrine
  •  Brompheniramine/Chlophedianol/Phenylephrine
  •  Brompheniramine/Carbetapentane/Phenylephrine
  •  Brimonidine/Timolol Ophthalmic
  •  Brigatinib
  •  Brexpiprazole
  •  Bortezomib
  •  Bisoprolol/Hydrochlorothiazide
  •  Bisoprolol
  •  Bismuth Subsalicylate/Metronidazole/Tetracycline
  •  Bismuth Subsalicylate
  •  Bismuth Subcitrate Potassium/Metronidazole/Tetracycline
  •  Bexarotene
  •   Betaxolol Ophthalmic
  •  Betaxolol
  •  Betamethasone
  •  Benzthiazide
  •  Benzphetamine
  •  Benzoic Acid/Methenamine/Sodium Salicylate
  •  Benzoic Acid/Hyoscyamine/Methenamine/Methylene Blue/Phenyl Salicylate
  •  Benzocaine/Phenylephrine/Phenylpropanolamine
  •  Bendroflumethiazide/Rauwolfia Serpentina
  •  Bendroflumethiazide/Nadolol
  •  Bendroflumethiazide
  •  Benazepril/Hydrochlorothiazide
  •  Benazepril
  •  Bazedoxifene/Conjugated Estrogens


Patients who are experiencing an episode of hypoglycemia should not use insulin. This is because insulin lowers blood glucose and could put the patient at risk.

If the patient is administering insulin in a public place (when travelling, for example), they are advised to carry glucose tablets or candy with them. This is because one of the most common side effects of regular human insulin injections is low blood sugar.

Different brands of insulin and different types of syringe exist. Patients are advised against changing their brand of insulin or type of administration equipment, because this could lead to the patient administering an incorrect dose.

Alcohol should be avoided by patients who use regular insulin. This is because alcohol can cause blood sugar to become dangerously low when consumed in conjunction with regular insulin injections.

Patients who experience itching, a skin rash which covers the entire body, difficulty breathing, a fast heart rate, sweating or a feeling of faintness may be allergic to insulin, and should get medical help immediately.

Type 1 diabetes patients should carry an ID card or wear a medical bracelet which states that they have the condition. In case of emergency, a doctor or emergency health care provider will be quickly and easily able to ascertain that the patient is diabetic and will be able to administer the appropriate emergency care.

Blood sugar levels can be drastically affected during times of stress, long-distance travel, surgery, vigorous exercise, excess alcohol intake, skipping meals and/or medical emergencies. Glucose levels should be carefully monitored in these instances, which in turn can mean that dose sizes and frequencies may also need to be altered. However, patients should not alter their dose schedule without first consulting their doctor or healthcare provider for advice.

Insulin is only one aspect of a diabetes treatment program which should also include weight control, exercise, diet restrictions, regular blood sugar testing and specialist medical care. Patients should follow the instructions of their doctor incredibly closely.


Regular human insulin is available in vials and cartridges. Unopened vials and cartridges should be stored in a refrigerator (between 2C to 8C), away from sources of heat, moisture and natural light, in the packaging they were shipped in.

Insulin should not be frozen. If insulin is inadvertently frozen, it should be disposed of by the patient.

Vials and cartridges which have been opened can be kept at a cool room temperature, away from sources of heat and light - they should not be stored in a bathroom and should be kept out of the reach of children and/or pets in a dedicated, locked medicine cabinet if possible. Opened vials and cartridges must be used with one calendar month.

Unused or expired insulin should be disposed of in a safe, hygenic manner, in accordance with FDA guidelines and state law. It should not be flushed down a toilet or drain. Instead, patients are advised to take unwanted insulin to a pharmacy which participates in a "take back"program. Patients can contact their local waste disposal department for further advice on how to avail of a tack-back program.


While regular human insulin is a greatly beneficial medication, it can also post a risk to patients who do not communicate effectively with their doctors. As a treatment designed to combat the effects of type 1 diabetes, insulin helps to regulate the level of glucose within the blood stream. However, it can also cause a number of unwanted side effects including hypoglycemia, dizziness, faintness, skin rash, abnormal heartbeat and more. These effects can severely impair the day-to-day functioning of the patient and even put them in perilous situations if the correct precautions are not taken.

Because these risks exist, it is important for the patient to be as upfront and forthcoming as possible regarding their own medical history, including any hereditary illnesses or diseases which run in the family. In addition to this, the patient should inform the doctor of their current medication treatment regimen, as there are hundreds of drugs which could potentially interact with regular insulin.

When taken regularly and correctly, insulin can help to almost completely eradicate the effects of type 1 diabetes, which can otherwise be untreatable in some patients. This allows the patient to enjoy a much greater quality of life. To achieve this, patient and doctor must work together to ensure blood glucose levels are regularly monitored and that dose sizes are optimized for the individual requirements of the patient.