Previous studies have assessed the prevalence and characteristics of self-medication in COVID-19. However, no systematic review has summarized their findings.
We conducted a systematic review to assess the prevalence of self-medication to prevent or manage COVID-19.
We used different keywords and searched studies published in PubMed, Scopus, Web of Science, Embase, two preprint repositories, Google, and Google Scholar. We included studies that reported original data and assessed self-medication to prevent or manage COVID-19. The risk of bias was assessed using the Newcastle–Ottawa Scale (NOS) modified for cross-sectional studies.
We identified eight studies, all studies were cross-sectional, and only one detailed the question used to assess self-medication. The recall period was heterogeneous across studies. Of the eight studies, seven assessed self-medication without focusing on a specific symptom: four performed in the general population (self-medication prevalence ranged between <4% to 88.3%) and three in specific populations (range: 33.9% to 51.3%). In these seven studies, the most used medications varied widely, including antibiotics, chloroquine or hydroxychloroquine, acetaminophen, vitamins or supplements, ivermectin, and ibuprofen. The last study only assessed self-medication for fever due to COVID-19. Most studies had a risk of bias in the “representativeness of the sample” and “assessment of outcome” items of the NOS.
Citation: Quincho-Lopez A, Benites-Ibarra CA, Hilario-Gomez MM, Quijano-Escate R, Taype-Rondan A (2021) Self-medication practices to prevent or manage COVID-19: A systematic review. PLoS ONE 16(11): e0259317. https://doi.org/10.1371/journal.pone.0259317
Editor: Muhammad Shahzad Aslam, Xiamen University - Malaysia Campus, MALAYSIA
Received: June 30, 2021; Accepted: October 16, 2021; Published: November 2, 2021
Copyright: © 2021 Quincho-Lopez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: The author(s) received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
With the progression of the COVID-19 pandemic, several medications have been proposed as potential candidates for this disease , most of which resulted in little or no benefit for the patients [2, 3] or even in harms . For example, hydroxychloroquine gained wide attention as a possible treatment for COVID-19 due to favorable results found in in-vitro or small uncontrolled studies . However, later, randomized trials in hospitalized patients, such as the RECOVERY trial  and the Solidarity trial , failed to find any clinical benefit compared to usual care. This is similar to what happened with azithromycin [7–10], while there are still few well-designed trials that have assessed other medications such as ivermectin [11–13] or vitamins supplements [14, 15].
Nonetheless, the fear of contracting the virus, low access to health services, and massive misinformation have led some people to self-medicate. According to the World Health Organization (WHO), self-medication “involves the use of medicinal products by the consumer to treat self-recognized disorders or symptoms.” . This may lead to unintended consequences, such as adverse events, unnecessary expenses, delay in attending professional evaluation, masking of symptoms, and drug interactions [17–19]. Self-medication prevalence varies according to several factors, such as the methodology used to assess self-medication , the population characteristics [20–22], and across different countries and contexts [23–25].
Previous studies have assessed the prevalence and characteristics of COVID-19 self-medication, reporting the use of several medications, herbal products, and dietary supplements as treatment or prevention for COVID-19 . However, to date, no systematic review has summarized their findings.
Thus, in this systematic review, we aimed to assess the prevalence of self-medication for the prevention or management of COVID-19. In addition, we assessed the type of medication used, reasons to practice self-medication, from where such medications were obtained, and adverse events due to its practice.
This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Supplementary Table S3) . The study protocol has been registered at PROSPERO (CRD42021236191).
2.1 Data sources
Search strategies were constructed a priori using different terms related to ‘COVID-19’ and ‘self-medication’ (S1 Table). On February 4th, 2021, we searched PubMed, Scopus, Web of Science, Embase, two preprint repositories (MedRxiv and SciELO Preprints), and grey literature sources (Google and Google Scholar). No language restriction was applied, but all the included articles were found written in English or Spanish. The search was restricted to include documents published in 2020 or 2021.
2.2 Inclusion criteria
We included original studies, either published in scientific journals or with full text available in preprint repositories, which reported original data and assessed the use of self-medication to prevent or manage COVID-19 as a primary or secondary outcome, in participants of any age and from any location.
We considered that a study assessed the use of self-medication in any of the following situations: 1) the study reported explicitly that self-medication was assessed (regardless of the definition used), or 2) the study assessed the use of medications without medical prescription.
2.3 Study selection
Two authors (AQL and MHG) independently selected the studies. For this, they first screened the search results by title and abstract according to the inclusion criteria using the web-based tool Rayyan (http://rayyan.qcri.org). Later, they reviewed the full text of the relevant studies to determine whether they were appropriate for study inclusion. Discrepancies were consulted with another author (ATR) and resolved by consensus.
2.4 Data extraction
Two authors (CBI and RQE) independently extracted the relevant data for the review using a pre-piloted Microsoft Excel spreadsheet. Again, any discrepancies were discussed with another author (ATR) and resolved with consensus.
Data on the following variables were extracted for each study: author, year of publication, country, study design, setting, population, sample technique, date of data collection, number of participants, age, sex, how was self-medication assessed, the prevalence of self-medication, reasons for practicing self-medication, who recommended such medication, from where was the medication obtained, and adverse events related to its use.
2.5 Risk of bias assessment
Two authors (CBI and RQE) independently evaluated the risk of bias for each included study using the Newcastle–Ottawa Scale (NOS) adapted for descriptive cross-sectional studies . This scale comprises two criteria: the selection criteria (representativeness of the sample, sample size, and nonresponders) and the outcome criteria (outcome assessment and statistical tests). Any discrepancy was discussed with another author (ATR).
3.1 Study selection
A total of 765 records were found in the database search. After the duplicates were eliminated, 227 records were screened, of which 46 documents were assessed in full-text. Lastly, 38 papers were excluded (which are detailed in S2 Table), and 8 papers were included, all of which were cross-sectional studies (Fig 1).
3.2 Methodological quality of the included studies
We assessed the risk of bias using the NOS. The study performed by Sadio  included two samples: one obtained using a probabilistic sample, and the other used a convenience sample. Thus, we assessed the risk of bias of these two samples separately.
Of the eight studies, only one (Sadio probabilistic sample) fulfilled the five stars in the NOS scale. In addition, the Sadio non-probabilistic sample, along with the other three studies, received four out of five stars. All studies except one (Sadio probabilistic sample) failed in fulfilling the representativeness of the sample item of the risk of bias assessment criteria (Table 1).
3.3 Studies characteristics
Studies characteristics are shown in Table 2. The eight included studies reported data on self-medication practices in six different countries: three from Peru [30–32], one from Bangladesh , one from Togo , one from Nigeria , one from Uganda , and one from the Kingdom of Saudi Arabia . All studies were cross-sectional. Regarding their publication, five studies were published as original reports [29, 30, 33, 34, 36], one was a letter to the editor , and two were preprints reporting original data [32, 35]. Studies were performed from March to August 2020.
Regarding the population, five studies were conducted targeting the general population, one was conducted in hospitalized patients with COVID-19 , one in healthcare undergraduate students , and one in workers from five sectors (health care, air transport, police, road transport, and informal) .
The eight studies included between 132 and 3,792 participants. Five studies mentioned the summary measure (mean or median) of the participants’ age. Such summary measure (either mean or median) ranged from 21 to 60.3 years. All studies were performed in adults. The percentage of females ranged from 28.4% to 69.1% (Table 2).
3.4 Definition of self-medication
All studies assessed self-medication through self-report. The questions used to assess self-medication were explicitly mentioned only in the one study , while other five studies report having asked for the use of medicine without prescription [29, 31–34], and two studies gave no details regarding how self-medication was measured in their surveys [30, 35]. Moreover, three of the eight studies [30, 32, 36] reported collecting only a pre-specified list of medications.
Regarding the recall period for which self-medication was assessed: three studies assessed it during the COVID-19 pandemic [33, 35, 36], one during the COVID-19 lockdown , one during the past three months , one during the past two weeks , one since the COVID-19 diagnosis , and one did not detail the recall period  (Table 2).
3.5 Prevalence of self-medication and most frequently used medications
As showed in Table 2, We classified the eight included studies into three groups: 1) those that assessed self-medication for COVID-19 prevention or management without focusing on a specific symptom, and 2) those that assessed self-medication for a specific COVID-19 symptom.
Seven studies were included in the first group (assessed self-medication for COVID-19 prevention or management without focusing on a specific symptom). Of these, four were performed in the general population (with a range of self-medication prevalence between <4% and 88.3%) and three in specific populations (which reported a self-medication prevalence of 33.9% for hospitalized adults with COVID-19, 34.2% in adults who worked in five assessed sectors, and 51.3% in undergraduate students of health-related careers).
Of these seven studies, six mentioned the list of medications reported by the participants. The reported medications were different across the studies: six studies reported the consumption of antibiotics, five of chloroquine or hydroxychloroquine, three of acetaminophen, three of vitamins or supplements, two of ivermectin, and two of ibuprofen.
In addition, consumption preferences varied across studies. For example, when medications were sorted in the order of highest to lowest consumption, vitamins/supplements occupied the first place in two studies, but the fourth place in another study (Table 2).
The second group (studies that assessed the use of medication for a specific symptom) included one study performed on the general population of Saudi Arabia, which found that 35.1% of the surveyed individuals used self-medication for fever  (Table 2).
3.6 Reasons to practice self-medication, from where were the medications obtained, and adverse effects
Four of the eight included studies mentioned the reasons for self-medication. However, each study assessed the reasons differently. Thus, one study referred only to the symptoms that motivated participants to self-medicate, and the other three collected a plethora of reasons, including the fear of stigmatization, fear of quarantine, affordability, the convenience of self-medication, and patients believing that the symptoms were not severe (Table 3).
Only one study  specified the source of the patients’ self-medications. This study was performed on adults from Nigeria. The most common sources reported were the pharmacy (73.9%) and the patent medicine vendor (23.6%).
Only two studies reported whether adverse events occurred in those who self-medicate. One study performed on Undergraduate students of health-related careers found that 11.7% of those who self-medicate presented with side effects of self-medication in the past three months . Nonetheless, this study did not specify the adverse effects that occurred. The second study, performed in adults from Nigeria, reported body rash (23.1%) followed by worsened condition (17.3%), yellowish eyes (7.7%), swollen face (3.8%), and vomiting of blood and severe diarrhea (5.8%) .
To our knowledge, this is the first systematic review to assess the self-medication prevalence for COVID-19 prevention or management. It assessed the most important databases and sources for grey literature search and preprints repositories; without language limitations. Thus, our results should reflect the state of knowledge until the search date.
Self-medication is a global phenomenon that may involve health risks at both the individual and community levels [19, 37]. Previous studies have found that self-medication is a common practice. Three systematic reviews conducted in Iran , Ethiopia , and India ; reported a prevalence of 53%, 44%, and 53.6%, respectively; for a recall period that ranged from a single day to 6 months.
In our review, we only found eight studies. Although the included studies were performed in six countries, the lack of studies in some regions such as North America, the Middle East, North Africa, and Oceania is evident. It is expected that the intercountry differences in drug promotion, regulations, and the possibility of accessing some medications without a prescription can influence the self-medication patterns [38, 39]. Moreover, seven of the eight included studies were performed in low- and middle-income countries. While self-medication may be higher in such countries, due to the conditions and structure of the health system , it is not possible to make solid comparisons due to the heterogeneity in the self-medication assessment across studies.
Some of the included studies assessed over-the-counter medications such as acetaminophen or nonsteroidal anti-inflammatory drugs, which are used for the symptom management of COVID-19, along with several other diseases. However, the included studies have also found an heterogeneous prevalence of self-medication with medications that have not proven to benefit in the prevention or management of COVID-19 (such as antibiotics, chloroquine or hydroxychloroquine, vitamins or supplements, ivermectin, and antiasthmatics), as stated by the current COVID-19 guidelines by WHO and IDSA [41, 42].
In fact, the adverse effects of some of these medications are of great concern, such as antibiotic resistance due to extensive antibiotic use, bleeding caused by aspirin use, inhibition of the immune system caused by corticosteroids, or arrhythmia caused by hydroxychloroquine . Some healthcare organizations have issued statements on self-medication. For instance, the WHO recognizes that a “successful” (i.e., beneficial) self-medication can be achieved in many countries only by improving individuals’ knowledge and education level in such a way that the potential damages of this practice can be avoided . Similarly, the International Pharmaceutical Federation, in tandem with the World Self-Medication Industry , and the World Medical Association , emphasizes the responsible use of non-prescription medications.
Similar to that found in previous systematic reviews [20, 21], the included studies in our review tended to use different questions to assess self-medication, or they did not specify the question used. Moreover, studies have established different recall periods, and even those that assessed self-medication since the beginning of the pandemic would have different time frames depending on the month in which they were performed. This lack of clear information prevents direct comparisons between studies and the subsequent meta-analysis of their results , adding a potential source of bias that affects the internal validity of the results [45, 46]. In addition, it is possible that studies that evaluated self-medication through a pre-specified list of medications reported biased prevalences, since these medications may not have included all the most commonly used medications .
The included studies had an important risk of bias, mainly in the “representativeness of the sample” domain of the NOS, the worst-rated item in the risk of bias assessment. This prevents the adequate extrapolation of the results , which should be taken into account when interpreting the results of this review.
Due to the limitations of the primary studies included in this review, more well-designed and adequately reported studies are needed, as well as the use of standardized self-medication definitions across studies. Moreover, since the COVID-19 status is changing rapidly, future studies are required to assess if there is any variation in self-medication trends between COVID-19 waves and after introducing the massive vaccination.
The findings of this review suggest that there is an important though heterogeneous prevalence of self-medication to prevent or manage COVID-19. This includes some medications that have not shown any benefit so far and may therefore expose people to unnecessary adverse events. The results vary widely across studies, suggesting that each context (region, country) has its own self-medication patterns and impact, calling on local health authorities to promote research and interventions to reduce potential self-medication adverse consequences.
Eight studies that assessed the use of self-medication for the prevention or management of COVID-19 were identified. The definition and recall period were heterogeneous across studies. Of the eight studies, seven assessed self-medication without focusing on a specific symptom: four performed in the general population (self-medication prevalence ranged between <4% to 88.3%) and three in specific populations (range: 33.9% to 51.3%). In these studies, the most commonly used medications varied widely, including antibiotics, chloroquine or hydroxychloroquine, acetaminophen, vitamins or supplements, ivermectin, and ibuprofen. The last study only assessed self-medication for fever due to COVID-19.
Based on four studies, fever, fear of stigmatization, affordability of self-medication, and believing that the symptoms were not severe were the most common reasons to practice self-medication. The pharmacy was the preferred source of medications whereas body rash and worsened condition were the most frequent adverse event related to self-medication according to one and two studies, respectively. Almost all studies failed in fulfilling the representativeness of the sample item of the risk of bias assessment criteria. Thus, more well-designed and adequately reported studies are warranted in this regard.
- 1. Sanders JM, Monogue ML, Jodlowski TZ, Cutrell JB. Pharmacologic Treatments for Coronavirus Disease 2019 (COVID-19): A Review. JAMA. 2020;323: 1824–1836. pmid:32282022
- 2. Lam S, Lombardi A, Ouanounou A. COVID-19: A review of the proposed pharmacological treatments. Eur J Pharmacol. 2020;886: 173451. pmid:32768505
- 3. WHO Solidarity Trial Consortium. Repurposed Antiviral Drugs for Covid-19—Interim WHO Solidarity Trial Results. N Engl J Med. 2021;384: 497–511. pmid:33264556
- 4. Kim MS, An MH, Kim WJ, Hwang TH. Comparative efficacy and safety of pharmacological interventions for the treatment of COVID-19: A systematic review and network meta-analysis. PLoS Med. 2020;17: e1003501. pmid:33378357
- 5. Ng TSB, Leblanc K, Yeung DF, Tsang TSM. Medication use during COVID-19. Can Fam Physician. 2021;67: 171–179. pmid:33727376
- 6. RECOVERY Collaborative Group. Effect of Hydroxychloroquine in Hospitalized Patients with Covid-19. N Engl J Med. 2020;383: 2030–2040. pmid:33031652
- 7. Furtado R, Berwanger O, Fonseca H, Al E. Azithromycin in addition to standard of care versus standard of care alone in the treatment of patients admitted to the hospital with severe COVID-19 in Brazil (COALITION II): a randomised clinical trial. Lancet. 2020;396: 959–967. pmid:32896292
- 8. Hinks TSC, Cureton L, Knight R, Wang A, Cane JL, Barber VS, et al. Azithromycin versus standard care in patients with mild-to-moderate COVID-19 (ATOMIC2): an open-label, randomised trial. Lancet Respir Med. 2021;19: 1130–1140. pmid:34252378
- 9. Oldenburg CE, Pinsky BA, Brogdon J, Chen C, Ruder K, Zhong L, et al. Effect of Oral Azithromycin vs Placebo on COVID-19 Symptoms in Outpatients with SARS-CoV-2 Infection: A Randomized Clinical Trial. JAMA. 2021;326: 490–498. pmid:34269813
- 10. PRINCIPLE Trial Collaborative Group. Azithromycin for community treatment of suspected COVID-19 in people at increased risk of an adverse clinical course in the UK (PRINCIPLE): a randomised, controlled, open-label, adaptive platform trial. Lancet. 2021;397: 1063–1074. pmid:33676597
- 11. Bartoszko JJ, Siemieniuk RAC, Kum E, Qasim A, Zeraatkar D, Ge L, et al. Prophylaxis against covid-19: Living systematic review and network meta-analysis. BMJ. 2021;373: n949. pmid:33903131
- 12. López-Medina E, López P, Hurtado IC, Dávalos DM, Ramirez O, Martínez E, et al. Effect of Ivermectin on Time to Resolution of Symptoms Among Adults With Mild COVID-19: A Randomized Clinical Trial. JAMA. 2021;325: 1426–1435. pmid:33662102
- 13. Vallejos J, Zoni R, Bangher M, Villamandos S, Bobadilla A, Plano F, et al. Ivermectin to prevent hospitalizations in patients with COVID-19 (IVERCOR-COVID19) a randomized, double-blind, placebo-controlled trial. BMC Infect Dis. 2021;21: 635. pmid:34215210
- 14. Thomas S, Patel D, Bittel B, Wolski K, Wang Q, Kumar A, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction among Ambulatory Patients with SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2021;4: e210369. pmid:33576820
- 15. Murai IH, Fernandes AL, Sales LP, Pinto AJ, Goessler KF, Duran CSC, et al. Effect of a Single High Dose of Vitamin D3on Hospital Length of Stay in Patients with Moderate to Severe COVID-19: A Randomized Clinical Trial. JAMA. 2021;325: 1053–1060. pmid:33595634
- 16. World Health Organization. Guidelines for the regulatory assessment of medicinal products for use in self-medication. 2000 [cited 10 Apr 2021]. Available: https://apps.who.int/iris/handle/10665/66154
- 17. Tasnim S, Hossain M, Mazumder H. Impact of rumors and misinformation on COVID-19 in Social Media. J Prev Med Public Heal. 2020;53: 171–174. pmid:32498140
- 18. Onchonga D, Omwoyo J, Nyamamba D. Assessing the prevalence of self-medication among healthcare workers before and during the 2019 SARS-CoV-2 (COVID-19) pandemic in Kenya. Saudi Pharm J. 2020;28: 1149–1154. pmid:32837218
- 19. Hughes CM, Mcelnay JC, Fleming GF. The benefits and risks of self-medication. Drug Saf. 2001;14: 1027–1037.
- 20. Shehnaz SI, Agarwal AK, Khan N. A systematic review of self-medication practices among adolescents. J Adolesc Heal. 2014;55: 467–483. pmid:25245937
- 21. Jerez-Roig J, Medeiros LFB, Silva VAB, Bezerra CLPAM, Cavalcante LAR, Piuvezam G, et al. Prevalence of Self-Medication and Associated Factors in an Elderly Population: A Systematic Review. Drugs and Aging. 2014;31: 883–896. pmid:25323057
- 22. Behzadifar M, Behzadifar M, Aryankhesal A, Ravaghi H, Baradaran HR, Sajadi HS, et al. Prevalence of self-medication in university students: Systematic review and meta-analysis. East Mediterr Heal J. 2020;26: 846–857. pmid:32794171
- 23. Azami-Aghdash S, Mohseni M, Etemadi M, Royani S, Moosavi A, Nakhaee M. Prevalence and cause of self-medication in Iran: A systematic review and meta-analysis article. Iran J Public Health. 2015;44: 1580–1593. pmid:26811809
- 24. Rashid M, Chhabra M, Kashyap A, Undela K, Gudi SK. Prevalence and Predictors of Self-Medication Practices in India: A Systematic Literature Review and Meta-Analysis. Curr Clin Pharmacol. 2019;15: 90–101.
- 25. Sisay M, Mengistu G, Edessa D. Epidemiology of self-medication in Ethiopia: A systematic review and meta-analysis of observational studies. BMC Pharmacol Toxicol. 2018;19: 56. pmid:30201045
- 26. Yáñez JA, Chung SA, Román BR, Hernández-Yépez PJ, Garcia-Solorzano FO, Del-Aguila-Arcentales S, et al. Prescription, over-the-counter (OTC), herbal, and other treatments and preventive uses for COVID-19. Environmental and Health Management of Novel Coronavirus Disease (COVID-19). 2021. pp. 379–416.
- 27. Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (prisma-p) 2015 statement. Syst Rev. 2015;4: 1. pmid:25554246
- 28. Herzog R, Álvarez-Pasquin MJ, Díaz C, Del Barrio JL, Estrada JM, Gil Á. Are healthcare workers intentions to vaccinate related to their knowledge, beliefs and attitudes? A systematic review. BMC Public Health. 2013;13: 154. pmid:23421987
- 29. Sadio A, Gbeasor-Komlanvi F, Konu R, Bakoubayi A, Tchankoni M, Bitty-Anderson A, et al. Assessment of self-medication practices in the context of Covid-19 outbreak in Togo. BMC Public Health. 2021;21: 58. pmid:33407321
- 30. Quispe-Cañari JF, Fidel-Rosales E, Manrique D, Mascaró-Zan J, Huamán-Castillón KM, Chamorro–Espinoza SE, et al. Self-medication practices during the COVID-19 pandemic among the adult population in Peru: A cross-sectional survey. Saudi Pharm J. 2021;29: 1–11. pmid:33519270
- 31. Zavala-Flores E, Salcedo-Matienzo J. Medicación prehospitalaria en pacientes hospitalizados por COVID-19 en un hospital público de Lima-Perú. Acta Medica Peru. 2020;37: 393–395.
- 32. Miñan-Tapia A, Conde-Escobar A, Calderon-Arce D, Cáceres-Olazo D, Peña-Rios AJ, Carlos Donoso-Romero R. Associated factors to self-medication with drugs related to COVID-19 in health science students from a peruvian city. SciELO Preprints [Preprint]. 2020 [cited 20 Apr 2021]. Available: https://doi.org/10.1590/SciELOPreprints.1225
- 33. Nasir M, Chowdhury ASMS, Zahan T. Self-medication during COVID-19 outbreak: a cross sectional online survey in Dhaka city. Int J Basic Clin Pharmacol. 2020;9: 1325–1330.
- 34. Wegbom AI, Edet CK, Raimi O, Fagbamigbe AF, Kiri VA. Self-Medication Practices and Associated Factors in the Prevention and/or Treatment of COVID-19 Virus: A Population-Based Survey in Nigeria. Front Public Heal. 2021;9: 606801. pmid:34150693
- 35. Dare S, Eze E, Isaac E, Usman I, Ssempijja F, Bukenya E, et al. COVID-19 pandemic and behavioural response to self-medication practice in Western Uganda. medRxiv: 20248576v1 [Preprint]. 2021 [cited 20 Apr 2021]. Available: https://doi.org/10.1101/2021.01.02.20248576
- 36. Mansuri FMA, Zalat MM, Khan AA, Alsaedi EQ, Ibrahim HM. Estimating the public response to mitigation measures and self-perceived behaviours towards the COVID-19 pandemic. J Taibah Univ Med Sci. 2020;15: 278–283. pmid:32837504
- 37. Bennadi D. Self-medication: A current challenge. J Basic Clin Pharm. 2013;5: 19–23. pmid:24808684
- 38. Leelavanich D, Adjimatera N, Broese Van Groenou L, Anantachoti P. Prescription and non-prescription drug classification systems across countries: Lessons learned for thailand. Risk Manag Healthc Policy. 2020;13: 2753–2768. pmid:33273873
- 39. Morgan DJ, Okeke IN, Laxminarayan R, Perencevich EN, Weisenberg S. Non-prescription antimicrobial use worldwide: A systematic review. Lancet Infect Dis. 2011;11: 692–701. pmid:21659004
- 40. Torres NF, Chibi B, Middleton LE, Solomon VP, Mashamba-Thompson TP. Evidence of factors influencing self-medication with antibiotics in low and middle-income countries: a systematic scoping review. Public Health. 2019;168: 92–101. pmid:30716570
- 41. World Health Organization. Therapeutics and COVID-19: living guideline. 2021 [cited 15 May 2021]. Available: https://www.who.int/publications/i/item/WHO-2019-nCoV-therapeutics-2021.1
- 42. Infectious Diseases Society of America (IDSA). IDSA Guidelines on the Treatment and Management of Patients with COVID-19. 2021 [cited 15 May 2021]. Available: https://www.idsociety.org/practice-guideline/covid-19-guideline-treatment-and-management/
- 43. Joint Statement by the International Pharmaceutical Federation and The World Self-Medication Industry. Responsible Self-Medication. 1999 [cited 20 Apr 2021]. Available: https://www.fip.org/file/1484
- 44. World Medical Association. WMA Statement on self-medication. 2017 [cited 10 Apr 2021]. Available: https://www.wma.net/policies-post/wma-statement-on-self-medication/
- 45. Limaye D, Limaye V, Krause G, Fortwengel G. A systematic review of the literature on survey questionnaires to assess self-medication practices. Int J Community Med Public Heal. 2017;4: 2620–2631.
- 46. Stull DE, Leidy NK, Parasuraman B, Chassany O. Optimal recall periods for patient-reported outcomes: Challenges and potential solutions. Curr Med Res Opin. 2009;25: 929–942. pmid:19257798
- 47. Choi B, Granero R, Pak A. Catalog of bias in health questionnaires. Rev Costarr Salud Pública. 2010;19: 106–118.
- 48. Andrade C. The Limitations of Online Surveys. Indian J Psychol Med. 2020;42: 575–576. pmid:33354086