insulin regular
Brand names: Humulin R, Novolin R
Humulin R is a short-acting insulin that helps control blood sugar levels in people with diabetes. It works quickly to lower blood sugar after meals.
Drug Pricing (NADAC)
Brand Price
$4.27/unit
Generic Available
No
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Humulin R is used to improve blood sugar control in adults and children with diabetes.
Common side effects
Low blood sugar (hypoglycemia), Reactions at the injection site (redness, swelling, itching), Skin thickening or pits at the injection site
Key warnings
Never share needles or syringes with anyone else, even if they are family.
How It Works
Humulin R is a type of insulin that replaces the insulin your body is not making. It helps sugar move from your blood into your cells, which lowers your blood sugar levels. This insulin starts working quickly and does not last very long.
How to Take It
Inject Humulin R under your skin about 30 minutes before you eat a meal. You can inject it into your thigh, upper arm, abdomen, or buttocks. Change your injection site each time to avoid skin problems. Your doctor will tell you how much insulin to use based on your blood sugar levels.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. Good control of diabetes is important during pregnancy. Discuss the risks and benefits of using Humulin R with your doctor if you are breastfeeding.
Missed Dose
If you miss a dose of Humulin R, check your blood sugar and take your next dose at your regular mealtime. Do not take a double dose to make up for the missed dose.
Storage
Store unopened Humulin R vials in the refrigerator. Once opened, keep the vial as cool as possible (below 86°F) and use within 31 days, even if there is insulin left.
Serious Warnings
Never share needles or syringes with anyone else, even if they are family. Sharing needles can spread blood-borne illnesses. Changes in your insulin dose should be made carefully under your doctor's supervision, as this can cause high or low blood sugar. Low blood sugar can be very dangerous and even life-threatening. If you have heart failure, talk to your doctor before using Humulin R, as it can worsen this condition.
Known Drug Interactions
7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.
Mechanism: Fluoxetine can increase the blood-sugar-lowering effect of insulin, which may cause your blood sugar to drop to an unsafe level.
What to do: Your doctor may need to change your insulin dose and you should check your blood sugar more often.
7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.
Mechanism: Pramlintide increases the risk of low blood sugar when used with insulin because both drugs work to lower glucose levels.
What to do: Your healthcare provider may need to adjust your insulin dose and you should monitor your blood sugar more closely.
7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.
Mechanism: Octreotide can lower blood sugar levels, which adds to the effect of insulin and increases the risk of a dangerous drop.
What to do: Your doctor may need to adjust your insulin dose and you should check your blood sugar levels more frequently.
Drugs that May Decrease the Blood Glucose Lowering Effect of HUMULIN R Drugs: Atypical antipsychotics (e.g., olanzapine and clozapine), corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens (e.g., in oral contraceptives), protease inhibitors, somatropin, sympathomimetic agents (e.g., albuterol, epinephrine, terbutaline), and thyroid hormones.
Mechanism: Albuterol can cause the body to produce more sugar or make it harder for insulin to lower it. This means your blood sugar might not drop as much as it usually does with insulin.
What to do: Monitor your blood sugar closely when starting or changing your dose of this medication. Your doctor may need to increase your insulin dose.
Drugs that May Increase or Decrease the Blood Glucose Lowering Effect of HUMULIN R Drugs: Alcohol, beta-blockers, clonidine, and lithium salts. Drugs that May Blunt Signs and Symptoms of Hypoglycemia Drugs: Beta-blockers, clonidine, guanethidine, and reserpine Intervention: Increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs. ( 7 ) Antiadrenergic Drugs (e.g., beta-blockers, clonidine, guanethidine, and reserpine): Signs and symptoms of hypoglycemia may be reduced or absent.
Mechanism: This drug can change how your body responds to insulin and may also hide the warning signs of low blood sugar, like a fast heartbeat. This makes it harder to tell if your blood sugar has dropped too low.
What to do: You should check your blood sugar more frequently because you might not feel the usual symptoms of a low. Your doctor will help you adjust your insulin dose as needed.
Common Questions
What should Humulin R look like?
Can I mix Humulin R with other insulins?
What if my blood sugar is too low?
What if my blood sugar is too high?
Can other medicines affect Humulin R?
What are the symptoms of low blood sugar?
What are the symptoms of high blood sugar?
Can I travel with Humulin R?
What should I do if I have an allergic reaction to Humulin R?
Who should not take Humulin R?
What are the common side effects of insulin regular?
Does insulin regular interact with other medications?
What drug class is insulin regular?
Is insulin regular safe during pregnancy?
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What the FDA Data Shows for insulin regular
The FDA label for insulin regular (sold under brand names such as Humulin R, Novolin R) classifies it as a prescription-only medication in the Short-Acting Insulin class. Humulin R is used to improve blood sugar control in adults and children with diabetes. Official labeling lists 7 commonly reported side effects, including Low blood sugar (hypoglycemia), Reactions at the injection site (redness, swelling, itching), Skin thickening or pits at the injection site.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. Voluntary reports accumulate over the lifetime of a drug and reflect wide-ranging clinical use. The database also lists 11 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 31, 2023
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages