ICD-10-CM Tag List · Table of Drugs · FY 2027 175 Codes

2027 Underdosing ICD-10-CM Codes ICD-10-CM

The FY 2027 dataset contains 175 underdosing codes across 15 code blocks. Underdosing codes document situations where a patient takes less of a prescribed drug than ordered, whether from financial limitations, misunderstanding of instructions, or intentional avoidance, potentially resulting in suboptimal treatment or complications. Each code below lists the substances that map to it in the Table of Drugs and Chemicals.

✓ Built from the official CMS FY 2027 datasetEffective Oct 1, 2026 – Sep 30, 2027
175
Codes
15
Code Blocks
0
Billable
FY 2027
Dataset

Coding Guidance

Underdosing codes are never principal diagnosis: code the relapse or exacerbation the underdosing caused first, and add a noncompliance code (Z91.12-, Z91.13-) when documented. No additional external cause code is required.

ICD-10-CM

All Underdosing Codes 175 codes · searchable by substance

175 of 175 shown

Poisoning by, adverse effect of and underdosing of systemic antibiotics T36 · 11 codes

  • T36.0X6 Underdosing of penicillinsNon-billable header
  • T36.1X6 Underdosing of cephalosporins and other beta-lactam antibioticsNon-billable header
  • T36.2X6 Underdosing of chloramphenicol groupNon-billable header
  • T36.3X6 Underdosing of macrolidesNon-billable header
  • T36.4X6 Underdosing of tetracyclinesNon-billable header
  • T36.5X6 Underdosing of aminoglycosidesNon-billable header
  • T36.6X6 Underdosing of rifampicinsNon-billable header
  • T36.7X6 Underdosing of antifungal antibiotics, systemically usedNon-billable header
  • T36.8X6 Underdosing of other systemic antibioticsNon-billable header
  • T36.96 Underdosing of unspecified systemic antibioticNon-billable header
  • T36.AX6 Underdosing of fluoroquinolone antibioticsNon-billable header

Poisoning by, adverse effect of and underdosing of other systemic anti-infectives and antiparasitics T37 · 8 codes

  • T37.0X6 Underdosing of sulfonamidesNon-billable header
  • T37.1X6 Underdosing of antimycobacterial drugsNon-billable header
  • T37.2X6 Underdosing of antimalarials and drugs acting on other blood protozoaNon-billable header
  • T37.3X6 Underdosing of other antiprotozoal drugsNon-billable header
  • T37.4X6 Underdosing of anthelminthicsNon-billable header
  • T37.5X6 Underdosing of antiviral drugsNon-billable header
  • T37.8X6 Underdosing of other specified systemic anti-infectives and antiparasiticsNon-billable header
  • T37.96 Underdosing of unspecified systemic anti-infectives and antiparasiticsNon-billable header

Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified T38 · 13 codes

  • T38.0X6 Underdosing of glucocorticoids and synthetic analoguesNon-billable header
  • T38.1X6 Underdosing of thyroid hormones and substitutesNon-billable header
  • T38.2X6 Underdosing of antithyroid drugsNon-billable header
  • T38.3X6 Underdosing of insulin and oral hypoglycemic [antidiabetic] drugsNon-billable header
  • T38.4X6 Underdosing of oral contraceptivesNon-billable header
  • T38.5X6 Underdosing of other estrogens and progestogensNon-billable header
  • T38.6X6 Underdosing of antigonadotrophins, antiestrogens, antiandrogens, not elsewhere classifiedNon-billable header
  • T38.7X6 Underdosing of androgens and anabolic congenersNon-billable header
  • T38.806 Underdosing of unspecified hormones and synthetic substitutesNon-billable header
  • T38.816 Underdosing of anterior pituitary [adenohypophyseal] hormonesNon-billable header
  • T38.896 Underdosing of other hormones and synthetic substitutesNon-billable header
  • T38.906 Underdosing of unspecified hormone antagonistsNon-billable header
  • T38.996 Underdosing of other hormone antagonistsNon-billable header

Poisoning by, adverse effect of and underdosing of nonopioid analgesics, antipyretics and antirheumatics T39 · 9 codes

  • T39.016 Underdosing of aspirinNon-billable header
  • T39.096 Underdosing of salicylatesNon-billable header
  • T39.1X6 Underdosing of 4-Aminophenol derivativesNon-billable header
  • T39.2X6 Underdosing of pyrazolone derivativesNon-billable header
  • T39.316 Underdosing of propionic acid derivativesNon-billable header
  • T39.396 Underdosing of other nonsteroidal anti-inflammatory drugs [NSAID]Non-billable header
  • T39.4X6 Underdosing of antirheumatics, not elsewhere classifiedNon-billable header
  • T39.8X6 Underdosing of other nonopioid analgesics and antipyretics, not elsewhere classifiedNon-billable header
  • T39.96 Underdosing of unspecified nonopioid analgesic, antipyretic and antirheumaticNon-billable header

Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens] T40 · 13 codes

  • T40.0X6 Underdosing of opiumNon-billable header
  • T40.2X6 Underdosing of other opioidsNon-billable header
  • T40.3X6 Underdosing of methadoneNon-billable header
  • T40.416 Underdosing of fentanyl or fentanyl analogsNon-billable header
  • T40.426 Underdosing of tramadolNon-billable header
  • T40.496 Underdosing of other synthetic narcoticsNon-billable header
  • T40.5X6 Underdosing of cocaineNon-billable header
  • T40.606 Underdosing of unspecified narcoticsNon-billable header
  • T40.696 Underdosing of other narcoticsNon-billable header
  • T40.716 Underdosing of cannabisNon-billable header
  • T40.726 Underdosing of synthetic cannabinoidsNon-billable header
  • T40.906 Underdosing of unspecified psychodysleptics [hallucinogens]Non-billable header
  • T40.996 Underdosing of other psychodysleptics [hallucinogens]Non-billable header

Poisoning by, adverse effect of and underdosing of anesthetics and therapeutic gases T41 · 7 codes

  • T41.0X6 Underdosing of inhaled anestheticsNon-billable header
  • T41.1X6 Underdosing of intravenous anestheticsNon-billable header
  • T41.206 Underdosing of unspecified general anestheticsNon-billable header
  • T41.296 Underdosing of other general anestheticsNon-billable header
  • T41.3X6 Underdosing of local anestheticsNon-billable header
  • T41.46 Underdosing of unspecified anestheticsNon-billable header
  • T41.5X6 Underdosing of therapeutic gasesNon-billable header

Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs T42 · 9 codes

  • T42.0X6 Underdosing of hydantoin derivativesNon-billable header
  • T42.1X6 Underdosing of iminostilbenesNon-billable header
  • T42.2X6 Underdosing of succinimides and oxazolidinedionesNon-billable header
  • T42.3X6 Underdosing of barbituratesNon-billable header
  • T42.4X6 Underdosing of benzodiazepinesNon-billable header
  • T42.5X6 Underdosing of mixed antiepilepticsNon-billable header
  • T42.6X6 Underdosing of other antiepileptic and sedative-hypnotic drugsNon-billable header
  • T42.76 Underdosing of unspecified antiepileptic and sedative-hypnotic drugsNon-billable header
  • T42.8X6 Underdosing of antiparkinsonism drugs and other central muscle-tone depressantsNon-billable header

Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified T43 · 19 codes

  • T43.016 Underdosing of tricyclic antidepressantsNon-billable header
  • T43.026 Underdosing of tetracyclic antidepressantsNon-billable header
  • T43.1X6 Underdosing of monoamine-oxidase-inhibitor antidepressantsNon-billable header
  • T43.206 Underdosing of unspecified antidepressantsNon-billable header
  • T43.216 Underdosing of selective serotonin and norepinephrine reuptake inhibitorsNon-billable header
  • T43.226 Underdosing of selective serotonin reuptake inhibitorsNon-billable header
  • T43.296 Underdosing of other antidepressantsNon-billable header
  • T43.3X6 Underdosing of phenothiazine antipsychotics and neurolepticsNon-billable header
  • T43.4X6 Underdosing of butyrophenone and thiothixene neurolepticsNon-billable header
  • T43.506 Underdosing of unspecified antipsychotics and neurolepticsNon-billable header
  • T43.596 Underdosing of other antipsychotics and neurolepticsNon-billable header
  • T43.606 Underdosing of unspecified psychostimulantsNon-billable header
  • T43.616 Underdosing of caffeineNon-billable header
  • T43.626 Underdosing of amphetaminesNon-billable header
  • T43.636 Underdosing of methylphenidateNon-billable header
  • T43.656 Underdosing of methamphetaminesNon-billable header
  • T43.696 Underdosing of other psychostimulantsNon-billable header
  • T43.8X6 Underdosing of other psychotropic drugsNon-billable header
  • T43.96 Underdosing of unspecified psychotropic drugNon-billable header

Poisoning by, adverse effect of and underdosing of drugs primarily affecting the autonomic nervous system T44 · 11 codes

  • T44.0X6 Underdosing of anticholinesterase agentsNon-billable header
  • T44.1X6 Underdosing of other parasympathomimetics [cholinergics]Non-billable header
  • T44.2X6 Underdosing of ganglionic blocking drugsNon-billable header
  • T44.3X6 Underdosing of other parasympatholytics [anticholinergics and antimuscarinics] and spasmolyticsNon-billable header
  • T44.4X6 Underdosing of predominantly alpha-adrenoreceptor agonistsNon-billable header
  • T44.5X6 Underdosing of predominantly beta-adrenoreceptor agonistsNon-billable header
  • T44.6X6 Underdosing of alpha-adrenoreceptor antagonistsNon-billable header
  • T44.7X6 Underdosing of beta-adrenoreceptor antagonistsNon-billable header
  • T44.8X6 Underdosing of centrally-acting and adrenergic-neuron-blocking agentsNon-billable header
  • T44.906 Underdosing of unspecified drugs primarily affecting the autonomic nervous systemNon-billable header
  • T44.996 Underdosing of other drug primarily affecting the autonomic nervous systemNon-billable header

Poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified T45 · 15 codes

  • T45.0X6 Underdosing of antiallergic and antiemetic drugsNon-billable header
  • T45.1X6 Underdosing of antineoplastic and immunosuppressive drugsNon-billable header
  • T45.2X6 Underdosing of vitaminsNon-billable header
  • T45.3X6 Underdosing of enzymesNon-billable header
  • T45.4X6 Underdosing of iron and its compoundsNon-billable header
  • T45.516 Underdosing of anticoagulantsNon-billable header
  • T45.526 Underdosing of antithrombotic drugsNon-billable header
  • T45.606 Underdosing of unspecified fibrinolysis-affecting drugsNon-billable header
  • T45.616 Underdosing of thrombolytic drugsNon-billable header
  • T45.626 Underdosing of hemostatic drugsNon-billable header
  • T45.696 Underdosing of other fibrinolysis-affecting drugsNon-billable header
  • T45.7X6 Underdosing of anticoagulant antagonist, vitamin K and other coagulantsNon-billable header
  • T45.8X6 Underdosing of other primarily systemic and hematological agentsNon-billable header
  • T45.96 Underdosing of unspecified primarily systemic and hematological agentNon-billable header
  • T45.AX6 Underdosing of immune checkpoint inhibitors and immunostimulant drugsNon-billable header

Poisoning by, adverse effect of and underdosing of agents primarily affecting the cardiovascular system T46 · 11 codes

  • T46.0X6 Underdosing of cardiac-stimulant glycosides and drugs of similar actionNon-billable header
  • T46.1X6 Underdosing of calcium-channel blockersNon-billable header
  • T46.2X6 Underdosing of other antidysrhythmic drugsNon-billable header
  • T46.3X6 Underdosing of coronary vasodilatorsNon-billable header
  • T46.4X6 Underdosing of angiotensin-converting-enzyme inhibitorsNon-billable header
  • T46.5X6 Underdosing of other antihypertensive drugsNon-billable header
  • T46.6X6 Underdosing of antihyperlipidemic and antiarteriosclerotic drugsNon-billable header
  • T46.7X6 Underdosing of peripheral vasodilatorsNon-billable header
  • T46.8X6 Underdosing of antivaricose drugs, including sclerosing agentsNon-billable header
  • T46.906 Underdosing of unspecified agents primarily affecting the cardiovascular systemNon-billable header
  • T46.996 Underdosing of other agents primarily affecting the cardiovascular systemNon-billable header

Poisoning by, adverse effect of and underdosing of agents primarily affecting the gastrointestinal system T47 · 10 codes

  • T47.0X6 Underdosing of histamine H2-receptor blockersNon-billable header
  • T47.1X6 Underdosing of other antacids and anti-gastric-secretion drugsNon-billable header
  • T47.2X6 Underdosing of stimulant laxativesNon-billable header
  • T47.3X6 Underdosing of saline and osmotic laxativesNon-billable header
  • T47.4X6 Underdosing of other laxativesNon-billable header
  • T47.5X6 Underdosing of digestantsNon-billable header
  • T47.6X6 Underdosing of antidiarrheal drugsNon-billable header
  • T47.7X6 Underdosing of emeticsNon-billable header
  • T47.8X6 Underdosing of other agents primarily affecting gastrointestinal systemNon-billable header
  • T47.96 Underdosing of unspecified agents primarily affecting the gastrointestinal systemNon-billable header

Poisoning by, adverse effect of and underdosing of agents primarily acting on smooth and skeletal muscles and the respiratory system T48 · 10 codes

  • T48.0X6 Underdosing of oxytocic drugsNon-billable header
  • T48.1X6 Underdosing of skeletal muscle relaxants [neuromuscular blocking agents]Non-billable header
  • T48.206 Underdosing of unspecified drugs acting on musclesNon-billable header
  • T48.296 Underdosing of other drugs acting on musclesNon-billable header
  • T48.3X6 Underdosing of antitussivesNon-billable header
  • T48.4X6 Underdosing of expectorantsNon-billable header
  • T48.5X6 Underdosing of other anti-common-cold drugsNon-billable header
  • T48.6X6 Underdosing of antiasthmaticsNon-billable header
  • T48.906 Underdosing of unspecified agents primarily acting on the respiratory systemNon-billable header
  • T48.996 Underdosing of other agents primarily acting on the respiratory systemNon-billable header

Poisoning by, adverse effect of and underdosing of topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinorlaryngological and dental drugs T49 · 10 codes

  • T49.0X6 Underdosing of local antifungal, anti-infective and anti-inflammatory drugsNon-billable header
  • T49.1X6 Underdosing of antipruriticsNon-billable header
  • T49.2X6 Underdosing of local astringents and local detergentsNon-billable header
  • T49.3X6 Underdosing of emollients, demulcents and protectantsNon-billable header
  • T49.4X6 Underdosing of keratolytics, keratoplastics, and other hair treatment drugs and preparationsNon-billable header
  • T49.5X6 Underdosing of ophthalmological drugs and preparationsNon-billable header
  • T49.6X6 Underdosing of otorhinolaryngological drugs and preparationsNon-billable header
  • T49.7X6 Underdosing of dental drugs, topically appliedNon-billable header
  • T49.8X6 Underdosing of other topical agentsNon-billable header
  • T49.96 Underdosing of unspecified topical agentNon-billable header

Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances T50 · 19 codes

  • T50.0X6 Underdosing of mineralocorticoids and their antagonistsNon-billable header
  • T50.1X6 Underdosing of loop [high-ceiling] diureticsNon-billable header
  • T50.2X6 Underdosing of carbonic-anhydrase inhibitors, benzothiadiazides and other diureticsNon-billable header
  • T50.3X6 Underdosing of electrolytic, caloric and water-balance agentsNon-billable header
  • T50.4X6 Underdosing of drugs affecting uric acid metabolismNon-billable header
  • T50.5X6 Underdosing of appetite depressantsNon-billable header
  • T50.6X6 Underdosing of antidotes and chelating agentsNon-billable header
  • T50.7X6 Underdosing of analeptics and opioid receptor antagonistsNon-billable header
  • T50.8X6 Underdosing of diagnostic agentsNon-billable header
  • T50.906 Underdosing of unspecified drugs, medicaments and biological substancesNon-billable header
  • T50.916 Underdosing of multiple unspecified drugs, medicaments and biological substancesNon-billable header
  • T50.996 Underdosing of other drugs, medicaments and biological substancesNon-billable header
  • T50.A16 Underdosing of pertussis vaccine, including combinations with a pertussis componentNon-billable header
  • T50.A26 Underdosing of mixed bacterial vaccines without a pertussis componentNon-billable header
  • T50.A96 Underdosing of other bacterial vaccinesNon-billable header
  • T50.B16 Underdosing of smallpox vaccinesNon-billable header
  • T50.B96 Underdosing of other viral vaccinesNon-billable header
  • T50.Z16 Underdosing of immunoglobulinNon-billable header
  • T50.Z96 Underdosing of other vaccines and biological substancesNon-billable header

The info icon lists every substance from the table that maps to the code. The filter above searches those substances too.

Questions About This Page

How do I find the right code for a specific drug?

Type the substance into the filter above. Every code on this page carries its full substance list from the Table of Drugs and Chemicals. For the complete six-column table, use the Table of Drugs and Chemicals.

Do these codes need an external cause code?

No. Poisoning, adverse effect, and underdosing codes from the T36 to T65 range carry the intent inside the code itself, so no additional external cause code is reported with them.

What 7th character do these codes take?

A for the initial encounter during active treatment, D for subsequent encounters during recovery, and S for sequela when coding late effects.

How many underdosing codes are there?

The FY 2027 dataset contains 175 underdosing codes across 15 code blocks.

Related References

Source: official CMS FY 2027 ICD-10-CM release, effective October 1, 2026 through September 30, 2027.