Additive effect

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Additive effect in pharmacology describes the situation when the combining effects of two drugs equal the sum of the effects of the two drugs acting independently. [1] [2] The concept of additive effect is derived from the concept of synergy. It was introduced by the scientists in pharmacology and biochemistry fields in the process of understanding the synergistic interaction between drugs and chemicals over the century.

Contents

Additive effect often occurs when two similar drugs are taken together to achieve the same degree of therapeutic effect while reducing the specific adverse effect of one particular drug. For example, aspirin, paracetamol, and caffeine are formulated together to treat pain caused by tension headaches and migraine.

Additive effect can be used to detect synergy as it can be considered as the baseline effect in methods determining whether drugs have synergistic effect. Synergistic effect is similar to additive effect, having a combination effect greater than additive effect. It can produce an effect of 2+2 > 4 when two drugs are used together. Additive effect can also be found in a majority of combination therapies, although synergistic effect is more common. If the combination of two drugs in combination therapy has an effect lower than the sum of the effects of the two drugs acting independently, also known as antagonistic effect, the drugs will seldom be prescribed together in the same therapy.

Drug or chemical combinations with additive effects can cause adverse effects. For example, co-administration of non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids increases the risk of gastric bleeding. [3]

History

The concept of additive effect is derived from the concept of drug synergy. Thus, the origin of additive effect dates back to the early twentieth century when the search for synergy started. During the search for synergy, the models of Loewe additivity and Bliss independence were proposed. [4] These models are capable of measuring the effects of drug combinations. Hence, Loewe additivity and Bliss independence were developed to determine whether an effect of a drug combination is synergistic or antagonistic. During the construction of these models, the concept of additive effect was introduced as the baseline for the determination of synergy and antagonism.

Types of Additive Effect

Additive effects can occur with drugs with either equivalent or overlapping actions, or independent actions.

Equivalent or overlapping actions

Many of the drugs in the same class exert additive effect as they have a similar therapeutic mechanism of action. For example, the calcium carbonate, magnesium, and aluminium salts are all antacids with the mechanism of using the negative ion to neutralize the acid in the stomach. [5] The antacids have no interaction between them, so they would be considered to have additive effect when taken together.

Drugs that are in the same class, but do not have the same target, may also act additively by interacting with different targets in the same pathway. For example, propofol and sevoflurane can both produce anesthetic effects. [6] Propofol can potentiate the activity of GABAA receptor and act on α, β and γ subunits, [7] [8] [9] while sevoflurane enhances the response of the GABAA receptor to endogenous GABA by binding to the α1-subunit. [10] By using Dixon up-down method, a trial has shown that the effect in producing anesthetic effects between propofol and sevoflurane is additive. [11]

Independent actions

Two drugs having different targets in unrelated pathways that ultimately result in the desired therapeutic result are considered to have additive effects with independent actions. For example, artemisinin and curcumin both exert antimalarial effects. Artemisinin works by being metabolized in the body into active metabolites. The metabolites would then create reactive oxygen species(ROS) that damage the parasites and kill them. [12] The mechanism of action of curcumin remains largely unknown, but the antiparasitic effect is believed to be associated with the potentiation of innate and adaptive immunological responses. [13] [14] The combined effects of artemisinin and curcumin each contribute to the death of parasites via different mechanisms and the effect is shown to be additive by fractional inhibitory concentrations. [15]

Drugs with the same target in different sites that produce additive effects are also considered as independent action. For example, doxorubicin and trabectedin can both produce anticancer effect. [16] Doxorubicin is a DNA intercalator that prefers to bind to AT regions, [17] while trabectedin forms guanine adduct in DNA to disrupt DNA repair system. [18] A recent study has shown that doxorubicin and trabectedin do not hinder each other and could produce an additive anticancer effect. [19]

Common misconceptions

The concept of additive effect is analogous to the concept of simple addition in mathematics. However, the additive effect is not simply the arithmetic summation of two (or more) drugs in most cases. [20] For an additive inhibition effect, drug A and drug B could each inhibit 20% individually, but the additive effect is not 40%. The effect cannot be simply arithmetic because if drug A and drug B each inhibits 60% cannot theoretically exert an inhibitory effect of 120%. With 60% inhibitory effect each, the remaining function would be at (1-60%)×(1-60%)=16%, meaning the additive inhibitory effect would be 84%. Since the application of additive effect is commonly seen in clinical practice, avoiding the common misconceptions of additive effect is crucial to understanding the clinical significance of additive effect.[ citation needed ]

Clinical Significance

Detection of synergy

One of the typical uses of additive effect is to detect synergy. [21] Additive effect can be considered as the baseline effect in methods of determining the presence of synergistic effect between two or more drugs. Synergistic effect is similar to additive effect. The only difference is it has a combination effect greater than additive effect. To be brief, synergy can produce an effect of 2 + 2 > 4 when drugs are used in combination. [22] The combination of angiotensin II receptor antagonist (ARB), Candesartan-cilexetil , and angiotensin-converting enzyme inhibitor (ACEI), Ramipril, demonstrates a synergistic effect in reducing systolic blood pressure. [23]

Detection of antagonism

The other use of additive effect is to detect antagonism. Similarly, additive effect can be considered as the baseline effect in methods of determining the presence of antagonistic effect between drugs. Pharmacists can confirm the presence of antagonism when the combination effect of drugs is less than additive effect. The combination of acetylsalicylic acid and ibuprofen demonstrates an antagonistic effect in relieving pain and inflammation. [3]

Combination therapy

The most common clinical usage of additive effect in pharmacology is combination therapy. Two or more therapeutic agents are used in combination therapy to treat a single disease. Different drugs in the same combination therapy act on different biological and biochemical pathways in the body to produce an additive effect.

An example of combination therapy demonstrating additive effect is the use of β-2 adrenergic receptor agonists together with inhaled corticosteroids. This is a treatment for two commonly seen pulmonary diseases, asthma and chronic obstructive pulmonary disease. β-2 adrenergic receptor agonists act as bronchodilators, having an effect of inducing bronchodilation to relieve bronchoconstriction; Inhaled corticosteroids act as anti-inflammatory drugs to decrease the inflammatory response. The two drugs act on different sites in the body. The corticosteroids also reverse and restore the function and number of β-2 adrenergic receptors in patients’ lungs in vivo. Meanwhile, the combined activity of two drugs resolves the problem of reduced sensitivity in some patients with chronic obstructive pulmonary disease towards inhaled corticosteroids. [24] A common drug from this example can be found is Seretide®, containing a long-acting β-2 adrenergic receptor agonist named as Salmeterol and a corticosteroid named as Fluticasone. [25]

Additive interaction can also be found in combination therapy for treating hypertension. The combination of angiotensin II receptor blockers (ARBs) and calcium channel blockers (CCBs) is one of the suggested antihypertensive therapies. ARBs inhibit the action of angiotensin II to decrease fluid retention and blood volume to decrease blood pressure, reduce vasoconstriction to decrease peripheral vascular resistance, and prevent vascular fibrosis to decrease vascular stiffness. CCBs are vasodilators inhibiting L-type voltage-operated calcium channels in the blood vessels to alleviate vasoconstriction resulting in a decrease in peripheral vascular resistance. The two types of drugs act on different pathways to produce an additive effect on lowering blood pressure without any increase in adverse effects. [26] This combination, with ARB, valsartan, and CCB, amlodipine, is a common treatment in high-risk hypertensive patients, especially the elderly. [27]

The treatment for another common disease, primary hypercholesterolemia, also demonstrates additive effect. Plant sterol-ester margarine and a common type of antihyperlipidaemic drug, cerivastatin, have an additive effect in reducing LDL cholesterol, without significant interaction between the two drugs. [28] Another drug combination with additive effect for hypercholesterolemia is niacin (vitamin B3) and simvastatin. This drug combination is also known as Simcor commercially. Niacin can reduce the secretion of LDL cholesterol and very-low-density lipoprotein cholesterol (VLDL cholesterol). On the other hand, simvastatin can reduce the synthesis of LDL cholesterol and triglycerides, and increase the level of high-density lipoprotein cholesterol (HDL cholesterol). Together, niacin and simvastatin reduce the level of LDL cholesterol and increases the level of HDL cholesterol, [23] therefore managing hypercholesterolemia effectively.

Optimal dosing

Additive interaction or additive effect can be found in the treatment of the majority of common diseases. The combination of drugs with different effects has the benefit of using each drug at its optimal dose. [29] This decreases the possibility of using a higher dose of a single medication if the previous dose is ineffective in treating diseases or relieving symptoms. The significance of using drugs with optimal dose is lowering the occurrence of intolerable side effects, adverse reactions, and possible drug toxicity in patient's body. This increases the safe use of drugs and increases patient compliance with the therapy. [30]

One of the examples is the use of calcium channel blocker and beta-blocker. They are drugs that can be used to treat stable angina. They can both decrease the frequency of angina, aiming to relieve the symptoms of angina. There are controlled, double blind clinical trials and studies involving patients with preserved left ventricular function demonstrating that the combination of calcium channel blocker and beta blocker has an additive cardio depressant effects when comparing with either drug class alone. [31] The combination therapy is used when a single medication fails to produce a therapeutic effect. Choosing the optimal dose of the two medications in the combination therapy prevents the use of an extreme high dose of a single medication alone, leading to adverse effects.

Adverse Effects

Drug combinations with additive effects have the potential to cause adverse effects. Adverse effects induced by drug combinations are not uncommon. The risk of having adverse effects is increased when the drug combination with additive effect has the same adverse effect. Thus, some drug combinations with additive effect are avoided. Below are commonly seen drug combinations with additive effect causing adverse effects.

ACEI and potassium-sparing diuretics

An example demonstrating how drug combination with additive effect can cause adverse effects is the co-administration of ACEI and potassium-sparing diuretics. [3] Despite having different mechanisms of action, the drugs are able to reduce potassium excretion from the body. Hence, both ACEI and potassium-sparing diuretics have the side effect of hyperkalemia. When two drugs are used together, the risk of having hyperkalemia is doubled. Since hyperkalemia has the potential to cause arrhythmia and metabolic acidosis, the combination of ACEI and potassium-sparing diuretics is avoided.

NSAIDs and glucocorticoids

Another example is the combination of non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids. [3] Although NSAIDs and glucocorticoids have different mechanisms of action, the drugs are able to diminish the protective effect of gastric mucosa from gastric acid. [32] [33] As a result, the concomitant use of NSAIDs and glucocorticoids increases the risk of gastric bleeding and worsens peptic ulcer disease. As a result, the combination of NSAIDs and glucocorticoids is not recommended.

See also

Related Research Articles

<span class="mw-page-title-main">Antacid</span> Substance that relieves stomach problems

An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts of aluminium, calcium, magnesium, or sodium. Some preparations contain a combination of two salts, such as magnesium carbonate and aluminium hydroxide.

An antiplatelet drug (antiaggregant), also known as a platelet agglutination inhibitor or platelet aggregation inhibitor, is a member of a class of pharmaceuticals that decrease platelet aggregation and inhibit thrombus formation. They are effective in the arterial circulation where classical Vitamin K antagonist anticoagulants have minimal effect.

<span class="mw-page-title-main">Lorazepam</span> Benzodiazepine medication

Lorazepam, sold under the brand name Ativan among others, is a benzodiazepine medication. It is used to treat anxiety disorders, trouble sleeping, severe agitation, active seizures including status epilepticus, alcohol withdrawal, and chemotherapy-induced nausea and vomiting. It is also used during surgery to interfere with memory formation and to sedate those who are being mechanically ventilated. It is also used, along with other treatments, for acute coronary syndrome due to cocaine use. It can be given by mouth or as an injection into a muscle or vein. When given by injection, onset of effects is between one and thirty minutes and effects last for up to a day.

<span class="mw-page-title-main">Propofol</span> Intravenous medication used in anaesthesia

Propofol, marketed as Diprivan, among other names, also known as 2,6-Diisopropylphenol, is a short-acting medication that results in a decreased level of consciousness and a lack of memory for events. Its uses include the induction and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. It is also used for status epilepticus if other medications have not worked. It is given by injection into a vein, and the maximum effect takes about two minutes to occur and typically lasts five to ten minutes. Propofol is also used for euthanasia in Canada.

Dyslipidemia is an abnormal amount of lipids in the blood. Dyslipidemia is a risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). ASCVD includes coronary artery disease, cerebrovascular disease, and peripheral artery disease. Although dyslipidemia is a risk factor for ASCVD, abnormal levels don't mean that lipid lowering agents need to be started. Other factors, such as comorbid conditions and lifestyle in addition to dyslipidemia, is considered in a cardiovascular risk assessment. In developed countries, most dyslipidemias are hyperlipidemias; that is, an elevation of lipids in the blood. This is often due to diet and lifestyle. Prolonged elevation of insulin resistance can also lead to dyslipidemia. Likewise, increased levels of O-GlcNAc transferase (OGT) may cause dyslipidemia.

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Postoperative nausea and vomiting (PONV) is the phenomenon of nausea, vomiting, or retching experienced by a patient in the postanesthesia care unit (PACU) or within 24 hours following a surgical procedure. PONV affects about 10% of the population undergoing general anaesthesia each year. PONV can be unpleasant and lead to a delay in mobilization and food, fluid, and medication intake following surgery.

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<span class="mw-page-title-main">Anthracycline</span> Class of antibiotics

Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from Streptomyces bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder cancer, and lung cancers. The first anthracycline discovered was daunorubicin, which is produced naturally by Streptomyces peucetius, a species of Actinomycetota. Clinically the most important anthracyclines are doxorubicin, daunorubicin, epirubicin and idarubicin.

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References

  1. Government of Canada, Canadian Centre for Occupational Health and Safety (2019). "Synergism and related terms : OSH Answers". www.ccohs.ca. Retrieved 2022-03-26.
  2. Rowland, M., & Tozer, T. (2011). Clinical pharmacokinetics and pharmacodynamics [electronic resource] : Concepts and applications (4th ed.). Philadelphia: Wolters Kluwer Health/Lippincott William & Wilkins.
  3. 1 2 3 4 Cascorbi, Ingolf (2012). "Drug interactions--principles, examples and clinical consequences". Deutsches Ärzteblatt International. 109 (33–34): 546–555, quiz 556. doi:10.3238/arztebl.2012.0546. ISSN   1866-0452. PMC   3444856 . PMID   23152742.
  4. Greco, W. R.; Bravo, G.; Parsons, J. C. (1995). "The search for synergy: a critical review from a response surface perspective". Pharmacological Reviews. 47 (2): 331–385. ISSN   0031-6997. PMID   7568331.
  5. Maton, P. N.; Burton, M. E. (1999). "Antacids revisited: a review of their clinical pharmacology and recommended therapeutic use". Drugs. 57 (6): 855–870. doi:10.2165/00003495-199957060-00003. ISSN   0012-6667. PMID   10400401. S2CID   46960343.
  6. Brohan, Janette; Goudra, Basavana G. (2017-10-01). "The Role of GABA Receptor Agonists in Anesthesia and Sedation". CNS Drugs. 31 (10): 845–856. doi:10.1007/s40263-017-0463-7. ISSN   1179-1934. PMID   29039138. S2CID   207486777.
  7. Sanna, E., Garau, F., & Harris, R. (1995). Novel properties of homomeric beta 1 gamma-aminobutyric acid type A receptors: Actions of the anesthetics propofol and pentobarbital. Molecular Pharmacology, 47(2), 213.
  8. Jones, M., Harrison, N., Pritchett, D., & Hales, T. (1995). Modulation of the GABAA receptor by propofol is independent of the gamma subunit. The Journal of Pharmacology and Experimental Therapeutics, 274(2), 962-968.
  9. Lam, Dennis W; Reynolds, James N (1998). "Modulatory and direct effects of propofol on recombinant GABAA receptors expressed in Xenopus oocytes: Influence of α- and γ2-subunits". Brain Research. 784 (1–2): 179–187. doi:10.1016/s0006-8993(97)01334-6. ISSN   0006-8993. PMID   9518600. S2CID   140204274.
  10. Garcia, Paul; Kolesky, Scott; Jenkins, Andrew (2010-03-01). "General Anesthetic Actions on GABAA Receptors". Current Neuropharmacology. 8 (1): 2–9. doi:10.2174/157015910790909502. ISSN   1570-159X. PMC   2866459 . PMID   20808541.
  11. Harris, R.; Lazar, O.; Johansen, J.; Sebel, P. (2006-06-01). "Interaction of Propofol and Sevoflurane on Loss of Consciousness and Movement to Skin Incision during General Anesthesia". Anesthesiology. 104 (6): 1170–1175. doi:10.1097/00000542-200606000-00011. ISSN   0003-3022. PMID   16732087. S2CID   7164486.
  12. Novaes, Rômulo Dias; Sartini, Marcus Vinicius Pessoa; Rodrigues, João Paulo Ferreira; Gonçalves, Reggiani Vilela; Santos, Eliziária Cardoso; Souza, Raquel Lopes Martins; Caldas, Ivo Santana (2016). "Curcumin Enhances the Anti-Trypanosoma cruzi Activity of Benznidazole-Based Chemotherapy in Acute Experimental Chagas Disease". Antimicrobial Agents and Chemotherapy. 60 (6): 3355–3364. doi:10.1128/AAC.00343-16. ISSN   0066-4804. PMC   4879395 . PMID   27001816.
  13. Allam, Gamal (2009). "Immunomodulatory effects of curcumin treatment on murine schistosomiasis mansoni". Immunobiology. 214 (8): 712–727. doi:10.1016/j.imbio.2008.11.017. PMID   19249123.
  14. Jagetia, Ganesh Chandra; Aggarwal, Bharat B. (2007-01-25). ""Spicing Up" of the Immune System by Curcumin". Journal of Clinical Immunology. 27 (1): 19–35. doi:10.1007/s10875-006-9066-7. ISSN   0271-9142. PMID   17211725. S2CID   21586221.
  15. Nandakumar, Dalavaikodihalli Nanjaiah; Nagaraj, Viswanathan Arun; Vathsala, Palakkod Govindan; Rangarajan, Pundi; Padmanaban, Govindarajan (2006). "Curcumin-Artemisinin Combination Therapy for Malaria". Antimicrobial Agents and Chemotherapy. 50 (5): 1859–1860. doi:10.1128/AAC.50.5.1859-1860.2006. ISSN   0066-4804. PMC   1472230 . PMID   16641461.
  16. Dang, Jingyi; Fu, Jun; Zhang, Zhao; Liu, Dong; Cheng, Debin; Fan, Hongbin (2021). "Comparison between trabectedin and doxorubicin in soft-tissue sarcomas: a systematic review and meta-analysis". Annals of Translational Medicine. 9 (24): 1764. doi: 10.21037/atm-21-6033 . ISSN   2305-5839. PMC   8756232 . PMID   35071458.
  17. Kellogg, G. E.; Scarsdale, J. N.; Fornari, F. A. (1998). "Identification and hydropathic characterization of structural features affecting sequence specificity for doxorubicin intercalation into DNA double-stranded polynucleotides". Nucleic Acids Research. 26 (20): 4721–4732. doi:10.1093/nar/26.20.4721. ISSN   0305-1048. PMC   147880 . PMID   9753742.
  18. Zewail-Foote, Maha; Li, Ven-Shun; Kohn, Harold; Bearss, David; Guzman, Mary; Hurley, Laurence H (2001). "The inefficiency of incisions of ecteinascidin 743–DNA adducts by the UvrABC nuclease and the unique structural feature of the DNA adducts can be used to explain the repair-dependent toxicities of this antitumor agent". Chemistry & Biology. 8 (11): 1033–1049. doi: 10.1016/s1074-5521(01)00071-0 . ISSN   1074-5521. PMID   11731295.
  19. Hemanta Baruah; Colin G. Barry; Ulrich Bierbach (2004). "Platinum-Intercalator Conjugates: From DNA-Targeted Cisplatin Derivatives to Adenine Binding Complexes as Potential Modulators of Gene Regulation". Current Topics in Medicinal Chemistry. 4 (15): 1537–1549. doi:10.2174/1568026043387313. ISSN   1568-0266. PMID   15579095.
  20. Chou, Ting-Chao (2006). "Theoretical Basis, Experimental Design, and Computerized Simulation of Synergism and Antagonism in Drug Combination Studies". Pharmacological Reviews. 58 (3): 621–681. doi:10.1124/pr.58.3.10. ISSN   0031-6997. PMID   16968952. S2CID   7055257.
  21. Roell, Kyle R.; Reif, David M.; Motsinger-Reif, Alison A. (2017). "An Introduction to Terminology and Methodology of Chemical Synergy—Perspectives from Across Disciplines". Frontiers in Pharmacology. 8: 158. doi: 10.3389/fphar.2017.00158 . ISSN   1663-9812. PMC   5397413 . PMID   28473769.
  22. Government of Canada, Canadian Centre for Occupational Health and Safety (2022). "Synergism and related terms : OSH Answers". www.ccohs.ca. Retrieved 2022-03-16.
  23. 1 2 Jia, Jia; Zhu, Feng; Ma, Xiaohua; Cao, Zhiwei W.; Li, Yixue X.; Chen, Yu Zong (2009). "Mechanisms of drug combinations: interaction and network perspectives". Nature Reviews Drug Discovery. 8 (2): 111–128. doi:10.1038/nrd2683. ISSN   1474-1776. PMID   19180105. S2CID   54466254.
  24. Johnson, Malcolm (2004). "Interactions between corticosteroids and beta2-agonists in asthma and chronic obstructive pulmonary disease". Proceedings of the American Thoracic Society. 1 (3): 200–206. doi:10.1513/pats.200402-010MS. ISSN   1546-3222. PMID   16113435.
  25. "Seretide Full Prescribing Information, Dosage & Side Effects | MIMS Hong Kong". www.mims.com. Retrieved 2022-04-18.
  26. Volpe, Massimo; Tocci, Giuliano (2012). "Rationale for triple fixed-dose combination therapy with an angiotensin II receptor blocker, a calcium channel blocker, and a thiazide diuretic". Vascular Health and Risk Management. 8: 371–380. doi: 10.2147/VHRM.S28359 . ISSN   1178-2048. PMC   3383291 . PMID   22745561.
  27. Kostis, John B. (2010). "Antihypertensive therapy with CCB/ARB combination in older individuals: focus on amlodipine/valsartan combination". American Journal of Therapeutics. 17 (2): 188–196. doi:10.1097/MJT.0b013e3181a2ba2d. ISSN   1536-3686. PMID   19433970. S2CID   205809141.
  28. Simons, Leon A. (2002). "Additive effect of plant sterol-ester margarine and cerivastatin in lowering low-density lipoprotein cholesterol in primary hypercholesterolemia". The American Journal of Cardiology. 90 (7): 737–740. doi:10.1016/s0002-9149(02)02600-0. ISSN   0002-9149. PMID   12356387.
  29. "Combination Cancer Therapy - Cancer". Merck Manuals Consumer Version. Retrieved 2022-03-16.
  30. Shenfield, G. M. (1982). "Fixed combination drug therapy". Drugs. 23 (6): 462–480. doi:10.2165/00003495-198223060-00003. ISSN   0012-6667. PMID   7049658. S2CID   25856967.
  31. Leon, Martin B.; Rosing, Douglas R.; Bonow, Robert O.; Epstein, Stephen E. (1985-01-25). "Combination therapy with calcium-channel blockers and beta blockers for chronic stable angina pectoris". American Journal of Cardiology. 55 (3): B69–B80. doi:10.1016/0002-9149(85)90615-0. ISSN   0002-9149. PMID   2857518.
  32. Hsiang, Kuo-Wei; Ng, Yee-Yung; Lu, Ching-Liang; Chen, Tseng-Shing; Lin, Hsiao-Yi; Luo, Jiing-Chyuan; Wu, Jia-Min; Lin, Han-Chieh; Chang, Full-Young; Lee, Shou-Dong (2010). "Corticosteroids therapy and peptic ulcer disease in nephrotic syndrome patients: Steroid therapy and peptic ulcer disease". British Journal of Clinical Pharmacology. 70 (5): 756–761. doi:10.1111/j.1365-2125.2010.03752.x. PMC   2997316 .
  33. Drina, Musa (2017-06-01). "Peptic ulcer disease and non-steroidal anti-inflammatory drugs". Australian Prescriber. 40 (3): 91–93. doi:10.18773/austprescr.2017.037. PMC   5478398 . PMID   28798512.