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Abbreviation for inorganic pyrophosphate (diphosphate).
Farlex Partner Medical Dictionary © Farlex 2012


Abbreviation for:
paired-pulse inhibition
partial permanent impairment
Partnerhip for Policy Implementation
Patient and Public Involvement 
patient package insert
peptidyl prolyl isomerase
portal perfusion index
postpartum interval
protein-protein interaction
proton-pump inhibitor  
purified porcine insulin
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


An agent that blocks a cellular receptor, stops a chemical reaction, prevents an enzyme from working, or suppresses a muscle or nerve.

ACE inhibitor

Any of a class of drugs that block the effects of angiotensin-converting enzyme, preventing the formation of angiotensin II and therefore preventing a rise in blood pressure. Drugs from this class are used to treat hypertension, heart failure, myocardial infarction, and, in diabetics, to prevent and treat chronic kidney disease.

acetylcholinesterase inhibitor

Cholinesterase inhibitor.

alpha–2 plasmin inhibitor

Alpha–2 antiplasmin.

alpha-glucosidase inhibitor

An oral drug that lowers blood sugars by preventing carbohydrate absorption from the gastrointestinal tract.

5-alpha reductase inhibitor

A medication to treat benign prostatic hyperplasia. It blocks the conversion of testosterone to dihydrotestosterone.

angiotensin-converting enzyme inhibitor

Abbreviation: ACE inhibitor.
Any of the therapeutic agents that inhibit conversion of angiotensin I to angiotensin II. ACE inhibitors are used to treat hypertension and heart failure and to protect kidney function in patients with diabetes mellitus.

aromatase inhibitor

Any of a class of drugs that block the synthesis of estrogen in the body. A number of these agents have been developed to treat breast cancer, which is often a hormone-responsive malignancy.

attachment inhibitor

Entry inhibitor.

bone resorption inhibitor

A class of drugs that prevent or retard osteoporosis. Examples include the bisphosphonates.

cholesteryl ester transfer protein inhibitor

Any drug that inhibits the transfer of cholesteryl esters from high-density lipoproteins (HDLs) to other lipoproteins. Drugs from this class increase HDL levels, potentially improving the lipid profiles of patients and decreasing their risk of atherosclerosis.

cholinesterase inhibitor

Abbreviation: ChEI
Any of a class of drugs that prevent the degradation of the neurotransmitter acetylcholine, which is involved in memory and learning. Drugs from this class are used to treat Alzheimer’s dementia.
Synonym: acetylcholinesterase inhibitor

competitive inhibitor

1. A chemical that binds to or blocks another reagent from participating in a reaction.
2. A medication, hormone, or other intercellular messenger that binds and blocks the cellular receptor or target enzyme of another agent. Drugs that act by competitive inhibition may treat or prevent disease by inactivating pathogenic enzymes or by blocking the effects of hormones or precursor molecules. For example, protease inhibitors interfere with production of human immunodeficiency virus (HIV) by binding and inactivating the protease enzyme; selective estrogen-receptor modulators limit the impact of estrogen by replacing this hormone on cells sensitive to its effects.

cyclooxygenase inhibitor

Any agent that suppresses inflammation by blocking the inflammatory effects of cyclooxygenase.

dipeptidyl peptidase-4 inhibitor

Abbreviation: DPP-4 inhibitor

direct thrombin inhibitor

Abbreviation: DP
Any medication or substance that interferes with the coagulation of blood by blocking the action of thrombin. Unlike heparins, which are anticoagulants that require the presence of antithrombin to inactivate thrombin, DTIs exert their effects without an intermediary. DTIs can be used to treat and prevent clots in both arteries and veins (although heparin and warfarin are usually preferred for these uses). They are an alternative to heparin in patients with a history of heparin-induced thrombocytopenia. The primary side effect of DTIs is bleeding.

DPP-4 inhibitor

dipeptidyl peptidase-4 inhibitor.

dual reuptake inhibitor

An antidepressant medication that works by blocking the reuptake of both serotonin and norepinephrine.

entry inhibitor

Any agent that prevents a pathogen (e.g., human immunodeficiency virus) from binding to cell membranes and infecting cells.
Synonym: attachment inhibitor

glycoprotein IIB/IIIa receptor inhibitor

Any of a class of drugs that block the fibrinogen receptor on the surface of platelets. Drugs from this class are used to treat acute myocardial infarction, unstable angina pectoris, and other acute coronary syndromes. The most common side effect of treatment with these drugs is bleeding.

HMG CoA enzyme inhibitor


integrase inhibitor

Any agent that prevents the human immunodeficiency virus from inserting its viral DNA into host cell chromosomes.

matrix metalloproteinase inhibitor

An agent that inhibits cancer cells by blocking their abilities to invade tissues, demand new blood supply, and metastasize.

metalloprotease inhibitor

Metalloproteinase inhibitor.

metalloproteinase inhibitor

Any of numerous compounds that inhibit the activity of the metalloproteinase family of enzymes. These agents share the ability to suppress or eliminate the enzyme activity of the metalloproteinases. Agents identified in this group include the tetracycline antibiotics, numerous specially designed synthetic peptides and proteins, chemicals such as ethylenediaminetetra-acetic acid (EDTA), and a variety of agents used in cancer chemotherapy. Synonym: metalloprotease inhibitor

monoamine oxidase inhibitor

Abbreviation: MAOI
Any of a group of drugs that can be used to treat depression and Parkinson's disease. Nonselective versions of these medications produced hypertensive crises and other severe side effects when they were taken with tyramine-containing foods (some cheeses) and several other drugs. Newer members of this class of drugs do not have these effects, but should be used with caution, esp. by those taking selective serotonin reuptake inhibitors.


MAOIs may have unfavorable drug-drug interactions with many anesthetics and should be discontinued approximately two weeks before surgery.
See: tyramine

neuraminidase inhibitor

Any of a class of antiviral drugs that block neuraminidase, which helps the influenza virus to bud from cells it has infected so that it can spread to other ciliated epithelial cells of the respiratory tract. Agents in this class include oseltamivir and zanamivir.

nonnucleoside analog reverse transcriptase inhibitor

Abbreviation: NNRTI
Any of a class of antiretroviral drugs used to treat those infected with HIV. NNRTIs bind with and inhibit the activity of reverse transcriptase, an enzyme needed to transcribe viral RNA into the host cell DNA. Examples include nevirapine, delavirdine, and efavirenz.

nucleoside reverse transcriptase inhibitor

Abbreviation: NRTI
Any of a class of antiretroviral drugs used to treat patients with HIV infection. NRTIs prevent transcription of viral RNA to host DNA by interfering with the action of the enzyme reverse transcriptase. Zidovudine, dideoxyinosine, zalcitabine, d4T, and abacavir are NRTIs. See: reverse transcriptase inhibitor

phosphodiesterase inhibitor

Abbreviation: PDE inhibitor
Any agent that blocks phosphodiesterase, inhibiting the production of second messengers within cells, such as cyclic adenosine monophosphate or cyclic glucose monophosphate. Drugs that inhibit PDE include sildenafil, an agent used to treat erectile dysfunction, and other agents used as positive inotropes and vasodilators in heart failure.

prostaglandin inhibitor

A substance that inhibits the production of prostaglandins. Nonsteroidal and steroidal anti-inflammatory agents are two major categories of such inhibitors.

protease inhibitor

1. A substance that inhibits the action of enzymes.
2. Any of a class of medications that prevent immature virions (as of hepatitis viruses or HIV) from assembling into structures capable of replication.

proton pump inhibitor

Abbreviation: PPI
Any of a class of medications that eliminate acid production in the stomach. Thes drugs are used to treat peptic ulcers, gastroesophageal reflux disease, Heliobacter pylori infection, and related disorders. Omeprazole and lansoprazole are members of this drug class.

reverse transcriptase inhibitor

Abbreviation: RTI
Any of a class of antiretroviral agents that competitively inhibit the reverse transcriptase enzyme of HIV and other viruses.
See: antiretroviral

selective serotonin reuptake inhibitor

Abbreviation: SSRI
Any of a class of drugs that interfere with serotonin transport, used in treating depression, obsessive-compulsive behaviors, eating disorders, and social phobias. Examples include fluoxetine (Prozac), paroxetine (Paxil), and sertraline.


The use of SSRIs in the treatment of depression may sometimes be associated with an increased risk of suicide, esp. during the initiation of treatment. The risk is greatest among children and adolescents. All patients who begin treatment with SSRIs should be monitored closely for evidence that they intend to harm themselves.

serine protease inhibitor

Abbreviation: serpin
Any of the compounds that inhibit platelet function and coagulation. Serpins have been used to reduce deposition of microemboli in cases of disseminated intravascular coagulation associated with sepsis.

serotonin and norepinephrine reuptake inhibitor

Abbreviation: SNRI
An antidepressant medication (such as duloxetine or venlafaxine) that elevates mood by blocking neurons from taking up both norepinephrine and serotonin. Combined reuptake inhibitors differ from medications such as sertraline (Zoloft) or fluoxetine (Prozac), which are relatively selective serotonin reuptake inhibitors, and from tricyclic antidepressants, which primarily prevent the reuptake of norepinephrine by brain cells. SNRIs treat neuropathic pain as well as depression.

tumor necrosis factor alpha inhibitor

A drug that blocks the effects of tumor necrosis factor alpha (TNF-alpha), a biologically active cytokine that is a critical element of the inflammatory response. Such drugs, which include adalimumab, etanercept, and infliximab, are agents used to treat autoimmune illnesses such as rheumatoid arthritis.


Because these drugs are immunologically active, patients with active infection or those with chronic infections such as tuberculosis should not use them. These agents also sometimes increase the risk of cancers and have rarely been associated with demyelinating diseases of the central nervous system such as multiple sclerosis.

vasopeptidase inhibitor

Any of a class of medications that blocks the actions of both angiotensin converting enzymes (ACE) and neural endopeptidase. Drugs from this class may be used to treat heart failure.

proton pump inhibitor

Abbreviation: PPI
Any of a class of medications that eliminate acid production in the stomach. Thes drugs are used to treat peptic ulcers, gastroesophageal reflux disease, Heliobacter pylori infection, and related disorders. Omeprazole and lansoprazole are members of this drug class.
See also: inhibitor
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
Crucially, even if people do not think they were mis-sold, there is also now another reason to complain about PPI.
PPI was unsuitable for some people, people did not realise it was optional, or in some cases, they did not even know they had a policy.
Alongside Dominic and the star of the PPI deadline campaign ads, 'Animatronic Arnie', the 'Pressure's on Panel' also features 90s fitness icon, Mr Motivator, who is providing support in jogging people's memory ahead of the 29 August 2019 deadline.
Plevin guidelines state that if the bank earned more than 50% commission on your PPI, and failed to tell you about it, you are entitled to the amount back - which comes in at an average 67%.
PPI reclaims are taxed in the year they are paid back, not the year you took the policy.
If the bank (outrageously) added an extra loan to your original loan just to pay for the PPI -- you get back any interest you were charged on this extra loan.
* Recalculated seasonal factors for the last 5 years (2014-2018) for PPI Final Demand-Intermediate Demand indexes,
Some PS31.5 billion has already been paid back between January 2011 and May 2018 to customers who complained about the way they were sold PPI. If you had a PPI policy you weren't happy about you can complain yourself - for free - and it might be easier than you think.
PPI's Medium Altitude Long Endurance (MALE) UAS system, designated the "SureCam", will meet an urgent requirement for surveillance operations to support the mission.
About a third of the atrial fibrillation patients received a proton pump inhibitor (PPI) without a clear indication, and the PPI recipients developed heart failure at 2.9 times the rate as patients not on a PPI, a statistically significant difference, Joao B.
THE Financial Conduct Authority is proposing to put a deadline of June 2019 on claiming PPI compensation.