Use patterns of over-the-counter (OTC) medications and perspectives on OTC medications among Korean adult patients with chronic diseases: gender and age differences

Figures & data

Figure 1 Flow diagram of steps in the selection of study subjects.

Table 1 Participant demographic and clinical characteristics

Characteristics	Total, n (%) (n=345)
Gender
Male	152 (44.1)
Female	193 (55.9)
Age (years), mean ± SD	61.4±12.3
<45	21 (6.1)
45–54	95 (27.5)
55–64	97 (28.1)
65–74	74 (21.4)
≥75	58 (16.8)
Types of insurance
National health insurance	315 (91.3)
National medical aid	29 (8.4)
Industrial accident compensation insurance	0 (0.0)
Car insurance	0 (0.0)
Others	1 (0.3)
Number of prescription medications taken by participants, mean ± SD	3.7±2.2
≤1	27 (7.8)
2–4	228 (66.1)
5–9	79 (22.9)
≥10	11 (3.2)
Ten most frequently diagnosed chronic diseases in participants
Hypertension	282 (81.7)
Diabetes mellitus	104 (30.1)
Hyperlipidemia	97 (28.1)
Gastroduodenitis	40 (11.6)
Gonarthrosis	11 (3.2)
Menopausal disorders	11 (3.2)
Heart failure	10 (2.9)
Gastroesophageal reflux disease	8 (2.3)
Dyspepsia	8 (2.3)
Muscle tension	8 (2.3)

Table 2 Participant demographic and clinical characteristics according to the use of OTC medications

Characteristics	OTC medication user, n (%) (n=224)	OTC medication non-user, n (%) (n=121)	P-valuea
Gender
Male	107 (47.8)	45 (37.2)	0.058
Female	117 (52.2)	76 (62.8)
Age (years)
<65	149 (66.5)	64 (52.9)	0.012
≥65	75 (33.5)	57 (47.1)
Number of prescription medications taken by participants
≤1	19 (8.5)	8 (6.5)	0.445
2–4	146 (65.2)	82 (67.8)
5–9	54 (24.1)	25 (20.7)
≥10	5 (2.2)	6 (5.0)
Chronic disease
Hypertension	183 (81.7)	99 (81.8)	0.978
Diabetes mellitus	62 (27.7)	42 (34.7)	0.174
Hyperlipidemia	60 (26.8)	37 (30.6)	0.455
Gastroduodenitis	23 (10.3)	17 (14.0)	0.295
Gonarthrosis	6 (2.7)	5 (4.1)	0.463
Menopausal disorders	8 (3.6)	3 (2.5)	0.582
Heart failure	3 (1.3)	7 (5.8)	0.019
Gastroesophageal reflux disease	4 (1.8)	4 (3.3)	0.371
Dyspepsia	2 (0.9)	6 (5.0)	0.017
Muscle tension	4 (1.8)	4 (3.3)	0.371

Note:

a Chi-squared test or Fisher’s exact test.

Abbreviation: OTC, over-the-counter.

Table 3 Prevalence and patterns of chronic diseases according to gender and age

Chronic diseases	Total, n (%) (n=345)	Gender			Age
		Male, n (%) (n=152)	Female, n (%) (n=193)	P-valuea	<65 years, n (%) (n=213)	≥65 years n (%) (n=132)	P-valuea
Hypertension	282 (81.7)	121 (79.6)	161 (83.4)	0.363	166 (77.9)	116 (87.9)	0.020
Diabetes mellitus	104 (30.1)	47 (30.9)	57 (29.5)	0.780	61 (28.6)	43 (32.6)	0.439
Hyperlipidemia	97 (28.1)	37 (24.3)	60 (31.1)	0.166	58 (27.2)	39 (29.5)	0.642
Gastroduodenitis	40 (11.6)	14 (9.2)	26 (13.5)	0.220	15 (7.0)	25 (18.9)	0.001
Gonarthrosis	11 (3.2)	0 (0.0)	11 (5.7)	0.003	2 (0.9)	9 (6.8)	0.003
Menopausal disorders	11 (3.2)	–	11 (5.7)	–	10 (4.7)	1 (0.8)	0.043
Heart failure	10 (2.9)	4 (2.6)	6 (3.1)	0.793	1 (0.5)	9 (6.8)	0.001
Gastroesophageal reflux disease	8 (2.3)	4 (2.6)	4 (2.1)	0.732	2 (0.9)	6 (4.5)	0.031
Dyspepsia	8 (2.3)	3 (2.0)	5 (2.6)	0.706	3 (1.4)	5 (3.8)	0.154
Muscle tension	8 (2.3)	4 (2.6)	4 (2.1)	0.732	1 (0.5)	7 (5.3)	0.004

Note:

a Chi-squared test or Fisher’s exact test.

Table 4 Participants’ OTC medication use patterns according to gender and age

OTC medication class	Total, n (%) (n=345)	Gender			Age
		Male, n (%) (n=152)	Female, n (%) (n=193)	P-valuea	<65 years, n (%) (n=213)	≥65 years n (%) (n=132)	P-valuea
Antipyretics, analgesics and anti-inflammatory drugs	150 (43.5)	66 (43.4)	84 (43.5)	0.985	105 (49.3)	45 (34.1)	0.006
Antihistamines	89 (25.8)	45 (29.6)	44 (22.8)	0.151	67 (31.5)	22 (16.7)	0.002
Digestives	62 (18.0)	31 (20.4)	31 (16.1)	0.298	40 (18.8)	22 (16.7)	0.619
Antitussives and expectorants	47 (13.6)	29 (19.1)	18 (9.3)	0.009	37 (17.4)	10 (7.6)	0.010
Antacids	33 (9.6)	20 (13.2)	13 (6.7)	0.044	25 (11.7)	8 (6.1)	0.081
Antiemetics	28 (8.1)	7 (4.6)	21 (10.9)	0.034	17 (8.0)	11 (8.3)	0.907
Multivitamins	26 (7.5)	11 (7.2)	15 (7.8)	0.852	13 (6.1)	13 (9.8)	0.200
Drugs for intestinal disorders	17 (4.9)	8 (5.3)	9 (4.7)	0.798	14 (6.6)	3 (2.3)	0.079
Antispasmodics	17 (4.9)	8 (5.3)	9 (4.7)	0.798	14 (6.6)	3 (2.3)	0.079
Drugs for peptic ulcer	12 (3.5)	6 (3.9)	6 (3.1)	0.673	8 (3.8)	4 (3.0)	1.000
Laxatives and enemas	7 (2.0)	2 (1.3)	5 (2.6)	0.472	6 (2.8)	1 (0.8)	0.258
Skeletal muscle relaxants	6 (1.7)	5 (3.3)	1 (0.5)	0.091	5 (2.3)	1 (0.8)	0.413
Contraceptives	4 (1.2)	–	4 (2.1)	–	4 (1.9)	–	–

Note:

a Chi-squared test or Fisher’s exact test.

Abbreviation: OTC, over-the-counter.

Table 5 Participants’ perspectives toward OTC medication use according to gender and age

	Total, n (%) (n=345)	Gender			Age
		Male, n (%) (n=152)	Female, n (%) (n=193)	P-valuea	<65 years, n (%) (n=213)	≥65 years n (%) (n=132)	P-valuea
Q1. What is your reason for using an OTC drug?
Pain	67 (19.4)	43 (28.3)	24 (12.4)	<0.001	54 (25.4)	13 (9.8)	<0.001
Cold	97 (28.1)	40 (26.3)	57 (29.5)	0.509	67 (31.5)	30 (22.7)	0.080
Dyspepsia	78 (22.6)	37 (24.3)	41 (21.2)	0.495	49 (23.0)	29 (22.0)	0.823
Heartburn	34 (9.9)	19 (12.5)	15 (7.8)	0.144	23 (10.8)	11 (8.3)	0.455
Fatigue	28 (8.1)	14 (9.2)	14 (7.3)	0.509	19 (8.9)	9 (6.8)	0.487
Diarrhea	6 (1.7)	1 (0.7)	5 (2.6)	0.235	5 (2.3)	1 (0.8)	0.413
Constipation	17 (4.9)	8 (5.3)	9 (4.7)	0.798	14 (6.6)	3 (2.3)	0.079
Others	48 (13.9)	20 (13.2)	28 (14.5)	0.719	23 (10.8)	25 (18.9)	0.034
Q2. How often had you used an OTC drug within the last 30 days?
<6	285 (82.6)	129 (84.9)	156 (80.8)	0.326	190 (89.2)	95 (72.0)	<0.001
≥6	60 (17.4)	23 (15.1)	37 (19.2)		23 (10.8)	37 (28.0)
Q3. Do you think that an OTC drug is effective?b
Mean ± SD	3.9±0.9	4.0±1.0	3.9±0.9	0.573	3.9±0.9	3.9±1.0	0.754
Q4. Do you think that pharmacists’ medication counseling is necessary when purchasing an OTC drug?b
Mean ± SD	4.0±1.1	4.0±1.2	4.0±1.0	0.978	4.0±1.1	4.0±1.0	0.840
Q5. Do you give pharmacists information on drugs which you currently take when purchasing an OT C drug?b
Mean ± SD	3.6±1.4	3.6±1.4	3.6±1.4	0.879	3.6±1.4	3.7±1.3	0.620
Q6. Do you know that an OTC drug can cause adverse reactions or interact with prescription drugs which you currently take?b
Mean ± SD	2.7±1.3	2.7±1.4	2.7±1.3	0.524	2.9±1.3	2.3±1.2	<0.001
Q7. Do you read the package leaflet of an OTC drug when using it?c
Mean ± SD	2.2±1.2	2.4±1.2	2.0±1.2	0.006	2.5±1.2	1.8±1.1	<0.001

Notes:

a Chi-squared test, Fisher’s exact test or independent t-test.

b Rating scale: 5= strongly agree, 4= agree, 3= neutral, 2= disagree and 1= strongly disagree.

c Rating scale: 4= strongly agree, 3= agree, 2= disagree and 1= strongly disagree.

Abbreviation: OTC, over-the-counter.

Table 6 Drug–drug interactions between drugs that participants had taken

Drugs	Interaction drug	Frequency of use	Severitya	Quality of evidenceb	Summary
Aspirin	Thiazide	6	Major	Good	Reduced diuretic effectiveness and possible nephrotoxicity
	Atenolol, bisoprolol, carvedilol	6	Moderate	Good	Decreased antihypertensive effect
	Meloxicam	2	Major	Fair	Increased risk of bleeding
	Ranitidine	6	Minor	Excellent	Decreased plasma levels of aspirin and its antiplatelet effect
	Al(OH)2, Mg(OH)2, MgO	5	Moderate	Fair	Decreased effectiveness of aspirin
Atenolol	Diltiazem	1	Major	Good	Increased risk of hypotension, bradycardia, AV conduction disturbances
	Glimepiride, metformin	3	Moderate	Good	Hypoglycemia or hyperglycemia, decreased symptoms of hypoglycemia
	Al(OH)2, Mg(OH)2, CaCO3	4	Minor	Good	Decreased effectiveness of atenolol
Belladonna	Chlorpheniramine	1	Minor	Fair	Excessive anticholinergic activity
Caffeine	Alprazolam, lorazepam	2	Minor	Good	Decreased sedative and anxiolytic effects of alprazolam and lorazepam
	Estradiol valerate, medroxyprogesterone	2	Moderate	Good	Enhanced central nervous system stimulation
Carvedilol	Metformin, sitagliptin	2	Moderate	Good	Hypoglycemia or hyperglycemia, decreased symptoms of hypoglycemia
Cilostazol	Ginkgo biloba	10	Major	Good	Increased risk of bleeding
Diltiazem	Clopidogrel	2	Major	Excellent	Decreased antiplatelet effect and increased risk of thrombotic events
	Ranitidine	1	Minor	Good	Increased diltiazem concentrations and possible cardiovascular toxicity
Fluconazole	Atorvastatin	1	Major	Fair	Increased risk of myopathy or rhabdomyolysis
	Tamsulosin	1	Moderate	Fair	Increased exposure of tamsulosin
	Tramadol	1	Major	Fair	Increased tramadol exposure and risk of toxicity
G. biloba	Thiazide	3	Moderate	Good	Increased blood pressure
Glimepiride	Carvedilol, nebivolol	2	Moderate	Good	Hypoglycemia or hyperglycemia, decreased symptoms of hypoglycemia
	Sitagliptin	8	Moderate	Fair	Increased risk of hypoglycemia
	Ranitidine	1	Moderate	Fair	Increased blood glucose-lowering effect and increased risk of hypoglycemia
	Thioctic acid	4	Major	Fair	Increased risk of hypoglycemia
Meloxicam	Angiotensin II receptor blockers	3	Moderate	Excellent	Renal dysfunction or decreased antihypertensive efficacy
	Thiazide	3	Major	Good	Reduced diuretic effectiveness and possible nephrotoxicity
	Carvedilol	1	Moderate	Good	Decreased antihypertensive effect
Prednisolone	Thiazide	1	Moderate	Fair	Hypokalemia
Rosuvastatin	Al(OH)2, Mg(OH)2	2	Moderate	Fair	Decreased rosuvastatin effectiveness
Thiazide	Ibuprofen	1	Major	Good	Reduced diuretic effectiveness and possible nephrotoxicity
	CaCO3	1	Moderate	Fair	Increased risk of hypercalcemia
Thioctic acid	Metformin, sitagliptin	4	Major	Fair	Increased risk of hypoglycemia
Tramadol	Amitriptyline	1	Major	Fair	Increased risk of seizure, serotonin syndrome, opioid toxicity and increased levels of tramadol

Notes:

a Contraindicated – the drugs are contraindicated for concurrent use; major – the interaction may be life-threatening and/or need medical intervention to minimize or prevent serious adverse effects; moderate – the interaction may exacerbate the patient’s condition and/or need an alternative therapy; minor – the interaction may cause an increase in the frequency or severity of side effects but would not need a major alternative therapy.

b Excellent – the existence of the interaction has clearly been established through controlled studies; good – the existence of the interaction is strongly suggested through documentation, but well-controlled studies are rare; fair – available documentation is poor, but pharmacologic concerns lead clinicians to suspect the existence of the interaction or documentation regarding pharmacologically similar drug is good.

Abbreviation: AV, atrioventricular.