Prescription medication · Short-Acting Insulin
insulin regular
Also sold as Humulin R, Novolin R. Humulin R is used to improve blood sugar control in adults and children with diabetes.
Data updated 2026-05-15
- 11
- InteractionsSeveral interactions
- $4.27
- Brand price (NADAC)
insulin regular (Humulin R) is a prescription Short-Acting Insulin. Humulin R is used to improve blood sugar control in adults and children with diabetes.
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.
Verify with FDA → · CMS NADAC pricing →
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.
The sections below are summarized in plain English from insulin regular's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
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.
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.
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.
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.
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.
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.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
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?
What pregnancy or breastfeeding source fields are listed for insulin regular?
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Common Drug Interactions
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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 are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
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. This registry does not provide medication decisions.
Last updated: October 31, 2023
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
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