Correction to: Treatment adherence and blood pressure outcome among hypertensive out-patients in two tertiary hospitals in Sokoto, Northwestern Nigeria.

"After publication of our article [1] we became aware that we had not obtained permission to reproduce the questions from the eight-item Morisky's Medication Adherence Scale.

Knowledge, awareness, perception and reporting of experienced adverse drug reactions among outpatients in Nigeria.

Background Higher incidence of adverse drug reactions (ADRs) remain a major cause of morbidity and mortality. Most targeted ADR reporting activities are mainly professional-centered with less attention to patients' knowledge, perception and selfreporting of experienced ADRs. Objectives To comprehensively evaluate patients' knowledge, awareness, perception and reporting of experienced ADRs. Setting Three public healthcare facilities in Ibadan, southwestern Nigeria. Method A questionnaire-guided cross-sectional interview of 1190 consented ambulatory adult patients consecutively recruited from various clinics of the selected hospitals between February and June 2018. The 32-item pretested questionnaire comprised open- and closed-ended questions, as well as open-ended questions with relevant prompts. Data were summarised using descriptive statistics, while Chi square was used to investigate association between relevant categorical variables at p < 0.05. Main outcome measure Knowledge, awareness, perception and reporting of experienced ADRs among patients. Results Response rate was 99.1%. Mean age was 40.6 ± 14.9 years. Forty-nine (4.1%) patients were aware of pharmacovigilance. A total of 964 (81.0%) correctly understood what can be regarded as serious adverse drug reactions (ADRs), 444 (37.3%) had previously experienced ADRs, while 77 (6.5%) experienced reactions with current medication(s). Of this, 64 (83.1%) made a report largely to physician (52; 81.3%). Summarily, reported reactions were more with antimalarials (214; 49.1%), with itching (168; 78.5%) constituting the most frequently occurring reaction. Use of text message (276; 27.2%) and filling of ADR report form (248; 24.4%) were topmost on the list of suggested methods for ADR reporting. There was a significant association between patient's age and awareness of pharmacovigilance (p = 0.015), while educational qualification (p = 0.001) significantly influenced tendency to make a report of experienced ADRs. Conclusion Approximately four percent of patients were aware of pharmacovigilance, while more than three-quarters correctly understood the concept of serious adverse drug reactions. A little above one-quarter had previously experienced one form of reaction or the other, with majority reporting such reactions to physician. Continuous education of stakeholders in pharmacovigilance activities is advocated, while patient's active involvement in spontaneous reporting of ADRs should be carefully considered.

In vitro modulation of cytochrome P450 isozymes and pharmacokinetics of caffeine by extracts of Hibiscus sabdariffa Linn calyx.

Background Hibiscus sabdariffa beverage (HSB) is widely consumed as a medicinal herb and sometimes used concomitantly with drugs. This study evaluated the in vitro inhibitory potential of the aqueous extract of H. sabdariffa calyces (AEHS) on selected cytochrome P450 (CYP) isozymes and the effect of HSB on the pharmacokinetics of caffeine in vivo. Methods In vitro inhibitions of eight major CYP isozymes by AEHS were estimated by monitoring CYP-specific model reactions of 10 CYP probe substrates using N-in-one assay method. Subsequently, an open, randomized, two-period crossover design was used to evaluate the effect of HSB on the pharmacokinetics of single-dose 200 mg caffeine in six healthy human volunteers. Blood samples were obtained at specific times over a 24 h period. Probe drugs and metabolites were analyzed in their respective matrices with ultra-performance liquid chromatography/mass spectrometer/mass spectrometer and reversed-phase high-performance liquid chromatography/ultraviolet detection. Results The H. sabdariffa aqueous extract weakly inhibited the selected CYP isozymes in vitro, with IC50 of >100 µgmL-1 in the order of CYP1A2 > CYP2C8 > CYP2B6 >> CYP2D6 > CYP2C19 > CYP3A4 > CYP2A6 > CYP2C9. HSB decreased terminal t1/2 and Tmax of caffeine by 13.6% and 13.0%, respectively, and increased Cmax by 10.3%. Point estimates of primary pharmacokinetic endpoints, Cmax = 1.142 (90% confidence interval (CI) = 0.882, 1.480) and AUC0-∞ = 0.992 (90% CI = 0.745, 1.320), were outside the 90% CI of 0.8-1.25 bioequivalence limits. Conclusion The aqueous extract of H. sabdariffa weakly inhibited eight CYP isozymes in vitro, but HSB modified the exposure to caffeine in human. Caution should be exercised in administering HSB with caffeine or similar substrates of CYP1A2 until more clinical data are available.

Potential inhibition of major human cytochrome P450 isoenzymes by selected tropical medicinal herbs-Implication for herb-drug interactions.

BACKGROUND: Increasing use of medicinal herbs as nutritional supplements and traditional medicines for the treatment of diabetes, hypertension, hyperlipidemia, and malaria fever with conventional drugs poses possibilities of herb-drug interactions (HDIs). The potential of nine selected widely used tropical medicinal herbs in inhibiting human cytochrome P450 (CYP) isoenzymes was investigated. MATERIALS AND METHODS: In vitro inhibition of eight major CYP isoenzymes by aqueous extracts of Allium sativum, Gongronema latifolium, Moringa oleifera, Musa sapientum, Mangifera indica, Tetracarpidium conophorum, Alstonia boonei, Bauhinia monandra, and Picralima nitida was estimated in human liver microsomes by monitoring twelve probe metabolites of nine probe substrates with UPLC/MS-MS using validated N-in-one assay method. RESULTS: Mangifera indica moderately inhibited CYP2C8, CYP2B6, CYP2D6, CYP1A2, and CYP2C9 with IC 50 values of 37.93, 57.83, 67.39, 54.83, and 107.48 µg/ml, respectively, and Alstonia boonei inhibited CYP2D6 (IC 50 = 77.19 µg/ml). Picralima nitida inhibited CYP3A4 (IC 50 = 45.58 µg/ml) and CYP2C19 (IC 50 = 73.06 µg/ml) moderately but strongly inhibited CYP2D6 (IC 50 = 1.19 µg/ml). Other aqueous extracts of Gongronema latifolium, Bauhinia monandra, and Moringa oleifera showed weak inhibitory activities against CYP1A2. Musa sapientum, Allium sativum, and Tetracarpidium conophorum did not inhibit the CYP isoenzymes investigated. CONCLUSION: Potential for clinically important CYP-metabolism-mediated HDIs is possible for Alstonia boonei, Mangifera indica, and Picralima nitida with drugs metabolized by CYP 2C8, 2B6, 2D6, 1A2, 2C9, 2C19, and 3A4. Inhibition of CYP2D6 by Picralima nitida is of particular concern and needs immediate in vivo investigations.

Treatment adherence and blood pressure outcome among hypertensive out-patients in two tertiary hospitals in Sokoto, Northwestern Nigeria.

BACKGROUND: Treatment adherence play important roles in blood pressure control leading to reduction in morbidity and mortality. This study therefore assessed adherence to pharmacological and non-pharmacological therapies among ambulatory hypertensive patients. Reasons for treatment non-adherence, and association between adherence and blood pressure were also investigated. METHODS: Cross-sectional questionnaire-guided interview and retrospective review of medical records of 605-patients from two-tertiary healthcare institutions in Sokoto, Northwestern Nigeria. Nine-item modified Morisky adherence scale was used to assess medication adherence. Overall adherence score to lifestyle modifications was obtained from the total scores from 4-domains of non-pharmacological measures including cigarette smoking and alcohol cessation, salt-restriction and exercise. Patient-specific adherence education was provided at contact to resolve the knowledge gap(s). Clinical-parameters were retrieved at contact and subsequent 2-months appointment. Descriptive statistics, Chi-square and Student's t-test were used for analysis at p < 0.05. RESULTS: Fifty-four (8.9%) patients were adherent to medications. Forgetfulness (404; 35.2%) was the most common reason for medication non-adherence. Use of buddy/companion reminder (605, 30.2%) top the list of adherence education. Overall adherence to lifestyle modifications was 36(6.0%). Mean systolic blood pressure (SBP) at contact was 149.6 ± 22.5 versus 134.2 ± 15.8 mmHg at 2-months with a 10% reduction. There were significant associations in baseline SBP for patients with or without adherence to medication, cigarette smoking cessation, and exercise (p < 0.05). CONCLUSIONS: Overall adherence to antihypertensive medications and lifestyle modifications is suboptimal, underscoring the need for continuous patient-specific adherence education to ensure better therapeutic outcomes.

A survey of the use of herbs among patients attending secondary-level health care facilities in southwestern Nigeria.

This study was carried out to evaluate the herb usage among patients attending secondary health facilities in Southwestern Nigeria. Data including allergies to drug and herbs, use of social drugs, and herbs and their perceived efficacy to herbs was collected from 265 patients (inpatients n = 65; outpatients n = 200) using structured questionnaire and patients' drug charts. A total of 15.4% of inpatients were found to be using herbs that may be potentially harmful due to drug-drug/drug-herb interactions. Nine percent experienced adverse effects with the use of herbs, whereas 2% experienced adverse reactions on coadministration with prescribed drugs. A high percent of outpatients, 38%, were using alcoholic beverages for extracting the plant materials themselves. The study showed that the use of herbs with drugs is widely practiced among patients attending secondary health care facilities in Nigeria, usually without the doctor or pharmacist's knowledge.