Bleeding and thrombosis outcomes in hospitalised COVID-19 patients on low-molecular-weight heparin and antiplatelet therapy.

BACKGROUND: An increased incidence of thromboembolic events in hospitalised COVID­19 patients has been demonstrated despite the use of low-molecular-weight heparin (LMWH). Antiplatelet therapy prior to admission and early in the disease course has been hypothesised to be protective against thrombosis. OBJECTIVES: To describe the bleeding and thrombosis outcomes in hospitalised patients with confirmed COVID­19 receiving LMWH, with and without concomitant antiplatelet therapy. Secondary objectives were to explore predictors of bleeding and thrombosis outcomes, and dosing practices of antiplatelet therapy and LMWH. METHODS: We conducted a descriptive, cross-sectional study of bleeding and thrombosis outcomes at Tygerberg Academic Hospital, Cape Town, South Africa, during the first COVID­19 wave, in 808 hospitalised patients with confirmed COVID­19 receiving LMWH with and without concomitant antiplatelet therapy. Multivariate logistic regression analysis was performed if predictors were deemed statistically and clinically significant. RESULTS: Patients receiving both LMWH and antiplatelet therapy had similar bleeding outcomes compared with patients only receiving LMWH (odds ratio (OR) 1.5; 95% confidence interval (CI) 0.6 - 4.0). Patients receiving both LMWH and antiplatelet therapy had increased odds of developing thrombosis compared with patients only receiving LMWH (OR 4.8; 95% CI 2.1 - 10.7). CONCLUSION: The bleeding risk in COVID­19 patients receiving both LMWH and antiplatelet therapy was not significantly increased. A potentially higher risk of thrombosis in patients receiving LMWH and antiplatelet therapy was observed. However, this could reflect confounding by indication. Randomised studies are required to further evaluate the use of antiplatelet therapy to treat hospitalised patients with COVID­19.

Ivermectin exposures reported to the Poisons Information Helpline in South Africa during the COVID-19 pandemic.

BACKGROUND: Ivermectin is an antiparasitic drug that has shown in vitro activity against COVID­19. Clinical studies supporting ivermectin for COVID­19 prevention and treatment are conflicting, with important limitations. Public support for ivermectin is significant, with extensive off-label use despite the conflicting views on its efficacy. Ivermectin tablets and injectable formulations are not registered in South Africa for human use by the South African Health Products Regulatory Authority. The National Department of Health does not currently recommend the use of ivermectin for COVID­19. OBJECTIVES: To describe cases of ivermectin exposure reported to the Poisons Information Helpline of the Western Cape (PIHWC) before and after publication of the drug's in vitro activity against SARS-CoV-2. METHODS: In a retrospective review, ivermectin-related calls reported to the PIHWC from 1 June 2015 to 30 June 2020 (period 1) were compared with calls received from 1 July 2020 to 31 July 2021 (period 2), dichotomised according to the first publication indicating ivermectin activity against SARS-CoV-2. RESULTS: Seventy-one cases were screened, and 65 were included for analysis; 19 cases were reported during period 1 and 46 during period 2. During period 2, 25 ivermectin cases (54.3%) were related to COVID­19 use. Of these, 24 cases (52.2%) involved veterinary preparations, 3 (6.5%) human preparations and 19 (41.3%) unknown preparations. Fourteen cases (73.7%) during period 1 and 30 (65.2%) during period 2 were reported to be symptomatic. The most common organ systems involved were the central nervous (n=26 cases; 40.0%), gastrointestinal (n=18; 27.7%), ocular (n=9; 13.8%) and dermatological (n=5; 7.7%) systems. CONCLUSION: Ivermectin-related exposure calls increased during study period 2, probably as a result of ivermectin being used as preventive and definitive therapy for COVID­19 in the absence of robust evidence on efficacy, dosing recommendations or appropriate formulations.

Bleeding and thrombosis outcomes in hospitalised COVID-19 patients on low-molecular-weight heparin and antiplatelet therapy

Background. An increased incidence of thromboembolic events in hospitalised COVID­19 patients has been demonstrated despite the use of low-molecular-weight heparin (LMWH). Antiplatelet therapy prior to admission and early in the disease course has been hypothesised to be protective against thrombosis.Objectives. To describe the bleeding and thrombosis outcomes in hospitalised patients with confirmed COVID­19 receiving LMWH, with and without concomitant antiplatelet therapy. Secondary objectives were to explore predictors of bleeding and thrombosis outcomes, and dosing practices of antiplatelet therapy and LMWH.Methods. We conducted a descriptive, cross-sectional study of bleeding and thrombosis outcomes at Tygerberg Academic Hospital, Cape Town, South Africa, during the first COVID­19 wave, in 808 hospitalised patients with confirmed COVID­19 receiving LMWH with and without concomitant antiplatelet therapy. Multivariate logistic regression analysis was performed if predictors were deemed statistically and clinically significant.Results. Patients receiving both LMWH and antiplatelet therapy had similar bleeding outcomes compared with patients only receiving LMWH (odds ratio (OR) 1.5; 95% confidence interval (CI) 0.6 - 4.0). Patients receiving both LMWH and antiplatelet therapy had increased odds of developing thrombosis compared with patients only receiving LMWH (OR 4.8; 95% CI 2.1 - 10.7).Conclusion. The bleeding risk in COVID­19 patients receiving both LMWH and antiplatelet therapy was not significantly increased. A potentially higher risk of thrombosis in patients receiving LMWH and antiplatelet therapy was observed. However, this could reflect confounding by indication. Randomised studies are required to further evaluate the use of antiplatelet therapy to treat hospitalised patients with COVID­19.

Comparison of patients with severe COVID-19 admitted to an intensive care unit in South Africa during the first and second wave of the COVID-19 pandemic.

Background: The second wave of coronavirus disease 2019 (COVID-19), dominated by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Beta variant, has been reported to be associated with increased severity in South Africa (SA). Objectives: To describe and compare clinical characteristics, management and outcomes of COVID-19 patients admitted to an intensive care unit (ICU) in SA during the first and second waves. Methods: In a prospective, single-centre, descriptive study, we compared all patients with severe COVID-19 admitted to ICU during the first and second waves. The primary outcomes assessed were ICU mortality and ICU length of stay (LOS). Results: In 490 patients with comparable ages and comorbidities, no difference in mortality was demonstrated during the second compared with the first wave (65.9% v. 62.5%, p=0.57). ICU LOS was longer in the second wave (10 v. 6 days, p<0.001). More female admissions (67.1% v. 44.6%, p<0.001) and a greater proportion of patients were managed with invasive mechanical ventilation than with non-invasive respiratory support (39.0% v. 14%, p<0.001) in the second wave. Conclusion: While clinical characteristics were comparable between the two waves, a higher proportion of patients was invasively ventilated and ICU stay was longer in the second. ICU mortality was unchanged.

Vasopressor therapy in atypical antipsychotic overdose.

Hypotension is a common presentation following an overdose of quetiapine. Adrenaline is often used as the vasopressor of choice for hypotension not responding to intravenous fluids. We present a case of quetiapine overdose with hypotension unresponsive to high-dose adrenaline. The patient was commenced on noradrenaline and made a full recovery. We highlight learning points about vasopressor therapy for atypical antipsychotic overdose. Quetiapine-induced hypotension is thought to be mediated by α1-receptor antagonism. Adrenaline is unlikely to improve blood pressure, as it is an agonist at both α- and ß-receptors. Alpha-2- and ß2-agonism can reduce sympathetic outflow and cause vasodilation, respectively, further exacerbating the hypotension. Noradrenaline is the preferred vasopressor of choice for hypotension caused by quetiapine overdose, as it has less affinity for α2- and ß2-receptors, but maintains α1-receptor agonism. Drugs with a similar mechanism of inducing hypotension should also be treated with noradrenaline as the vasopressor of choice.

Medical cannabis: What practitioners need to know.

The South African (SA) Constitutional Court recently decriminalised the private cultivation, possession and use of cannabis by adults. Cannabis contains varying amounts of the cannabinoids delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), depending on various cultivation factors. No commercial plant-derived cannabis products are currently registered by the SA Health Products Regulatory Authority (SAHPRA) for medical use. Such products are therefore unregulated, but are freely available in SA, and may be of inadequate quality and unverified composition, and not guaranteed to be safe or effective. SAHPRA has to date approved only one synthetic medical cannabis product, dronabinol. Evidence supporting benefit from medical cannabis exists for two drug-resistant childhood forms of epilepsy, Dravet syndrome and Lennox-Gastaut syndrome. Adjuvant therapy with medical cannabis can reduce seizure frequency for Lennox-Gastaut syndrome and Dravet syndrome by 18.8% and 22.8%, respectively, and may be beneficial for other rare forms of epilepsy. There is moderate evidence for chemotherapy-induced nausea and vomiting with the synthetic cannabinoids. Multiple sclerosis-associated spasticity showed a small clinical improvement in self-reported spasticity when a purified form of THC/CBD was added to existing therapy. Currently, low-level or no convincing evidence exists for the use of medical cannabis for chronic pain, sleep and weight disorders, and neuropsychiatric disorders. Cannabis is associated with a greater risk of adverse effects than active and placebo controls, and may be involved in clinically significant drug-drug interactions. The evolving regulatory and legal landscape on the use of medical cannabis will guide prescription and recreational use in the coming years.

Current evidence for directed and supportive investigational therapies against COVID-19.

Coronavirus disease 2019 (COVID-19) is a global health crisis. There is currently a great need for effective and safe therapies directed at the disease, but no drugs are presently registered for use in COVID-19. Several directed therapies have been proposed, and most are still in clinical trials. Currently available published, peer-reviewed results mostly involve small sample sizes with study limitations restricting the interpretation of the findings. Many trials currently published also do not have a control group, limiting the interpretation of the effect of the intervention. Investigational directed therapies as well as investigational supportive therapies against COVID-19 are reviewed here. Chloroquine and hydroxychloroquine show promise as directed therapies, but current trial results are conflicting. Lopinavir/ritonavir also shows potential, but was started late in the disease course in most trials. No randomised controlled evidence is currently available for remdesivir and favipiravir. Corticosteroid use is not recommended for directed therapy against COVID-19, and the role of tocilizumab is currently unclear, based on limited evidence. Early initiation of investigational directed therapies may provide benefit in selected patients. The results from larger randomised controlled trials will clarify the place of these therapies in COVID-19 treatment.

Paediatric antimicrobial use at a South African hospital.

BACKGROUND: Data on antimicrobial use among hospitalized children in Africa are very limited due to the absence of electronic prescription tracking. METHODS: This study evaluated antimicrobial consumption rates, the antimicrobial spectrum used, and the indications for therapy on a paediatric ward and in the paediatric intensive care unit (PICU) at Tygerberg Hospital, Cape Town, South Africa. Antimicrobial prescription and patient demographic data were collected prospectively from May 10, 2015 to November 11, 2015. For the same period, data on antimicrobials dispensed and costs were extracted from the pharmacy electronic medicine management system. The volume of antimicrobials dispensed (dispensing data) was compared with observed antimicrobial use (prescription data). RESULTS: Of the 703 patients admitted, 415/451 (92%) paediatric ward admissions and 233/252 (92%) PICU admissions received ≥1 antimicrobials. On the ward, 89% of prescriptions were for community-acquired infections; 29% of PICU antimicrobials were prescribed for healthcare-associated infections. Ampicillin and third-generation cephalosporins were the most commonly prescribed agents. Antimicrobial costs were 67541 South African Rand (ZAR) (5680 United States Dollars (USD)) on the ward and 210484 ZAR (17702 USD) in the PICU. Ertapenem and meropenem were the single largest contributors to antimicrobial costs on the ward (43%) and PICU (30%), respectively. The volume of antimicrobials dispensed by the pharmacy (dispensing data) differed considerably from observed antimicrobial use (prescription data). CONCLUSIONS: High rates of antimicrobial consumption were documented. Community-acquired infections were the main indication for prescription. Although pharmacy dispensing data did not closely approximate observed use, this represents a promising method for antimicrobial usage tracking in the future.

Therapeutic drug monitoring of amlodipine and the Z-FHL/HHL ratio: Adherence tools in patients referred for apparent treatment-resistant hypertension.

BACKGROUND: Non-adherence to antihypertensives is a cause of 'pseudo-treatment-resistant' hypertension. OBJECTIVE: To determine whether monitoring plasma amlodipine concentrations and inhibition of angiotensin-converting enzyme (ACE) can be adjunct adherence tools. METHODS: Patients with hypertension who were prescribed enalapril and amlodipine were enrolled. Blood pressures (BPs) were monitored and an adherence questionnaire was completed. Steady-state amlodipine was assayed using liquid chromatography-mass spectrometry and degree of ACE inhibition using the Z-FHL/HHL (z-phenylalanine-histidine-leucine/hippuryl-histidine-leucine) ratio. RESULTS: One hundred patients (mean (standard deviation) age 50.5 (12) years, 46% male) were enrolled. Based on plasma assays, 26/97 patients (26.8%) were unsuppressed by enalapril and 20/100 (20%) were sub-therapeutic for amlodipine. There were significant BP differences based on plasma levels of the medication: 21/20 mmHg lower in the group with suppressed ACE and 26/20 mmHg in the group with steady-state amlodipine concentrations. CONCLUSIONS: Monitoring antihypertensive adherence by assaying plasma medication concentrations is a feasible option for evaluating true v. pseudo-resistant hypertension.

Therapeutic drug monitoring of amlodipine and the Z-FHL/HHL ratio: Adherence tools in patients referred for apparent treatment-resistant hypertension

Background. Non-adherence to antihypertensives is a cause of 'pseudo-treatment-resistant' hypertension.Objective. To determine whether monitoring plasma amlodipine concentrations and inhibition of angiotensin-converting enzyme (ACE) can be adjunct adherence tools.Methods. Patients with hypertension who were prescribed enalapril and amlodipine were enrolled. Blood pressures (BPs) were monitored and an adherence questionnaire was completed. Steady-state amlodipine was assayed using liquid chromatography-mass spectrometry and degree of ACE inhibition using the Z-FHL/HHL (z-phenylalanine-histidine-leucine/hippuryl-histidine-leucine) ratio.Results. One hundred patients (mean (standard deviation) age 50.5 (12) years, 46% male) were enrolled. Based on plasma assays, 26/97 patients (26.8%) were unsuppressed by enalapril and 20/100 (20%) were sub-therapeutic for amlodipine. There were significant BP differences based on plasma levels of the medication: 21/20 mmHg lower in the group with suppressed ACE and 26/20 mmHg in the group with steady-state amlodipine concentrations.Conclusions. Monitoring antihypertensive adherence by assaying plasma medication concentrations is a feasible option for evaluating true v. pseudo-resistant hypertension

The pharmacokinetics of lopinavir/ritonavir when given with isoniazid in South African HIV-infected individuals.

Isoniazid preventive therapy is recommended in patients on antiretroviral treatment (ART) with latent tuberculous infection to prevent progression to active tuberculosis disease. Isoniazid (INH) inhibits cytochrome (CY) P3A4, which metabolises lopinavir (LPV). The administration of INH may cause higher LPV concentrations, which may increase LPV toxicity. LPV bioavailability is increased by co-formulated ritonavir (r), which may enhance the interaction of INH on LPV. We studied the effect of INH on LPV concentrations by administering INH for 7 days and performing intensive pharmacokinetic sampling in 16 human immunodeficiency virus infected patients established on LPV/r-based ART. INH did not significantly increase steady-state LPV area under the plasma concentration-time curve calculated for the 12 h-dosing interval.

The pharmacokinetics of nevirapine when given with isoniazid in South African HIV-infected individuals.

Isoniazid preventive therapy (IPT) is recommended in patients on antiretroviral treatment. Isoniazid (INH) inhibits CYP3A4, which metabolises nevirapine (NVP). Administration of INH may cause higher NVP concentrations and toxicity. We studied the effect of INH on NVP concentrations in 21 patients randomised to either placebo (n = 13) or INH (n = 8) in an ongoing trial of IPT in patients on ART. INH was associated with a 24% increase in median NVP area under the plasma concentration-time curve for the 12 h dosing interval, which was not statistically significant (P = 0.66).