Drug Interactions. Methylphenidate, dexamfetamine and lisdexamfetamine: • Methylphenidate may possibly enhance anticoagulant effect of coumarins. • Risk of hypertensive crisis when stimulants given with MAOIs and moclobemide. Amfetamine should not be administered during or within 14 days following the administration of monoamine oxidase inhibitors (MAOI) as it can increase the release of norepinephrine and other monoamines. This can cause severe headaches and other signs of hypertensive crisis. A variety of toxic neurological effects and malignant hyperpyrexia can occur, sometimes with fatal outcomes. • Methylphenidate possibly inhibits metabolism of SSRIs and tricyclics and so contributes to increase risk of side effects from these medications. • Stimulants may decrease the effect of drugs used to treat hypertension. • Because a predominant action of stimulants is to increase extracellular dopamine levels, caution is recommended when administering stimulants with dopaminergic drugs, including antipsychotics. • Seizures are a potential risk with stimulant medication. Caution is advised with concomitant use of medicinal drugs which are known to lower the seizure threshold (such as antidepressants, neuroleptics, mefloquine, bupropion, or tramadol). • QT interval prolongation is an increased risk when stimulants are administered with other QT prolonging drugs (such as antipsychotics, anti-arrhythmics, moxifloxacin, erythromycin, methadone, mefloquine, tricyclic antidepressants, lithium) and drugs that cause electrolyte imbalance (such as thiazide diuretics). • Methylphenidate possibly increases plasma concentration of phenytoin, phenobarbital and primidone. • Alcohol may exacerbate adverse CNS effects therefore it is advisable to abstain from alcohol during treatment. • Ascorbic acid and other agents and conditions (diets high in fruits and vegetables, urinary tract infections and vomiting) that acidify urine increase urinary excretion and decrease the half-life of amfetamine. Sodium bicarbonate and other agents and conditions (thiazide diuretics, diets high in animal protein, diabetes, respiratory acidosis) that alkalinise urine decrease urinary excretion and extend the half-life of amfetamine.
Drug Interactions. Some medication combinations are dangerous and can lead to adverse reactions, such as difficulty breathing and lowered alertness, resulting in blackouts, unintentional overdose, or death. Potential interactions are more significant in people over age sixty-five or with underlying lung disease. ⬩ Alcohol ⬩ Benzodiazepines (Xanax, Valium, Ativan, etc.) ⬩ Muscle relaxers (Flexeril, methocarbamol, soma, etc). ⬩ Opioids (morphine, oxycodone, hydrocodone, Percocet, Codeine, Lortab, Vicodin, Tramadol, etc.) ⬩ Antihistamines available in many over-the-counter medications. ⬩ Tylenol (acetaminophen) may be an ingredient in prescription pain medications and are available in many over the counter medications and may exceed the recommended daily limit. Acetaminophen poisoning is one of the leading causes of acute liver failure. People who drink alcohol regularly or occasional binge drink are at higher risk. People with compromised liver function are at extremely high risk. ⬩ Methadone.
Drug Interactions. In vitro studies show that bicalutamide inhibits enzymes of the cytochrome P450 system, and may displace warfarin from plasma protein binding sites. Concomitant use of other enzyme inhibitors, e.g. cimetidine, could theoretically increase plasma concentrations of bicalutamide with the potential for increased adverse effects. In clinical practice, drug interactions are not generally seen (expert opinion). Caution is advised when drugs with a narrow therapeutic index are given with bicalutamide e.g. ciclosporin, where dose reductions and monitoring of plasma levels may be necessary. Caution should also be exercised with calcium channel blockers. Cost: At current prices, one year's treatment costs £4.98 (Drug Tariff Dec 2019) with bicalutamide 50mg/day
Drug Interactions. There is low potential for drug-drug interactions (see SPC). In postmenopausal women with osteoporosis the pharmacokinetics and pharmacodynamics of denosumab were not altered by previous alendronate therapy, based on data from a transition study (alendronate to denosumab). References Prescribing of Denosumab (Prolia®) in Wales: Review – Shared care protocol All Wales Medicines Strategy Group MTRAC Commissioning guidance sheet for denosumab, updated June 2019 CG146 Osteoporosis: assessing the risk of fragility fracture TA204 Denosumab for the prevention of osteoporotic fractures in postmenopausal women. NICE 2010 Amgen Limited. Prolia. Summary of Product Characteristics 2018. Cellulitis – acute xxxx://xxx.xxxx.xxx.xx/cellulitis-acute Denosumab: monitoring recommended Denosumab (Xgeva▼, Prolia); intravenous bisphosphonates: osteonecrosis of the jaw—further measures to minimise risk. MHRA (2015) Denosumab 60 mg (Prolia): rare cases of atypical femoral fracture with long-term use. MHRA 2013 Denosumab (Prolia, Xgeva▼): reports of osteonecrosis of the external auditory canal MHRA (2017) This ESCA should be read in conjunction with the Summary of Product Characteristics (SPC) and the Midlands Therapeutics Review and Advisory Committee (MTRAC) guidance sheet
Drug Interactions. Hydroxychloroquine may increase plasma digoxin levels and reduce effectiveness of amiodarone. It may enhance the effects of a hypoglycaemic treatment. Antacids may reduce absorption of hydroxychloroquine so it is advised that a 4-hour interval be observed between hydroxychloroquine and antacid use.
Drug Interactions. The use of aliskiren in combination with ARBs or ACEIs is contraindicated in patients with diabetes mellitus or renal impairment (GFR < 60 ml/min/1.73 m2) It is recommended that the effects of furosemide be monitored when initiating and adjusting furosemide or aliskiren therapy to avoid changes in extracellular fluid volume and possible situations of volume overload. Digoxin bioavailability may be slightly decreased by Xxxxxxxxx. Preliminary data suggest that irbesartan may decrease Aliskiren AUC and Cmax. The concomitant use of aliskiren with highly potent P-glycoprotein (P-gp) inhibitors (ciclosporin, quinidine, and verapamil), is contraindicated. Because of the risk of therapeutic failure, fruit juices and herbal teas should not be taken whilst a patient is being treated with aliskiren. Caution should be exercised when aliskiren is administered with ketoconazole or other moderate P-gp inhibitors (itraconazole, clarithromycin, telithromycin, erythromycin, amiodarone). No relevant interactions with have been observed when aliskiren is used with P-gp substrates or weak inhibitors (atenolol, digoxin, amlodipine or cimetidine). Inducers of P-gp (St. John's wort, rifampicin) may decrease the bioavailability of Aliskiren. Based on experience with the use of other substances that affect the renin-angiotensin system, concomitant use of potassium-sparing diuretics, potassium supplements, salt substitutes containing potassium or other substances that may increase serum potassium levels (e.g. heparin) may lead to increases in serum potassium. If co-medication is considered necessary, caution is advisable. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the antihypertensive effect of aliskiren. In some patients with compromised renal function (eg, dehydrated or elderly patients) aliskiren given concomitantly with NSAIDs may result in further deterioration of renal function, including possible acute renal failure, which is usually reversible when treatment is stopped. Meals with a high fat content have been shown to reduce the absorption of aliskiren substantially. The manufacturer’s summary of product characteristics (SPC) and the most current edition of the British National Formulary should be consulted for full information on contra-indications, warnings, side-effects and drug interactions. References
Drug Interactions. Adrenoreceptor blocking agents (e.g. propanolol), lithium and α methyltyrosine may antagonise the effects of dexamfetamine. Disulfiram may inhibit metabolism and excretion. The concurrent use of tricyclic antidepressants may increase the risk of cardiovascular side effects.Concurrent use of MAOI’s or use within the preceding 14 days may precipitate a hypertensive crisis. Concurrent use of beta-blockers may result in severe hypertension and dexamfetamine may result in diminished effect of other anti-hypertensives such as guanethidine. Phenothiazines may inhibit the actions of dexamfetamine. Amfetamines may delay the absorption of ethosuximide, phenobarbital and phenytoin. Acute dystonia has been noted with concurrent administration of haloperidol. Haloperidol and Chlorpromazine block dopamine and norepinephrine re-uptake, thus inhibiting the central stimulant effects of amfetamines. The analgesic effect of morphine may be increased and its respiratory depressant effects decreased with concurrent use of morphine and dexamfetamine. Amfetamines potentiate the analgesic effects of meperidine. Concomitant administration of clonidine and dexamfetamine may result in an increased duration of action of dexamfetamine. Gastrointestinal acidifying agents (guanethidine, reserpine, glutamic acid HCl, ascorbic acid, fruit juices, etc.) lower absorption of dexamfetamine. Urinary acidifying agents (ammonium chloride, sodium acid phosphate, etc.) increase urinary excretion of dexamfetamine. Both groups of agents lower blood levels and efficacy of dexamfetamine. Gastrointestinal alkalizing agents (sodium bicarbonate, etc) increase the absorption of amfetamines. Urinary alkalizing agents (acetazolamide, some thiazides) increase the concentration of the non-ionized species of the amfetamine molecule, thereby decreasing urinary excretion. Both groups of agents increase blood levels and efficacy of amfetamines. Alcohol may exacerbate the CNS adverse reactions of psychoactive drugs, including dexamfetamine. It is therefore advisable for patients to abstain from alcohol during treatment.
Drug Interactions. EXPAREL can be administered in the ready to use suspension or diluted to a concentration of up to 0.89 mg/mL (i.e., 1:14 dilution by volume) with normal (0.9%) saline or lactated Ringer’s solution. EXPAREL must not be diluted with water or other hypotonic agents as it will result in disruption of the liposomal particles. EXPAREL should not be admixed with local anesthetics other than bupivacaine. Non- bupivacaine based local anesthetics, including lidocaine, may cause an immediate release of bupivacaine from EXPAREL if administered together locally. The administration of EXPAREL may follow the administration of lidocaine after a delay of 20 minutes or more. Bupivacaine HCl administered together with EXPAREL may impact the pharmacokinetic and/or physicochemical properties of EXPAREL, and this effect is concentration dependent. Therefore, bupivacaine HCl and EXPAREL may be administered simultaneously in the same syringe, and bupivacaine HCl may be injected immediately before EXPAREL as long as the ratio of the milligram dose of bupivacaine HCl solution to EXPAREL does not exceed 1:2. The toxic effects of these drugs are additive and their administration should be used with caution including monitoring for neurologic and cardiovascular effects related to toxicity [See Dosage and Administration (2.2), Warnings and Precautions (5.1) and Overdosage (10)]. Other than bupivacaine as noted above, EXPAREL should not be admixed with other drugs prior to administration.
Drug Interactions. Pharmacists should monitor for potential drug interactions in this patient group as they would for any prescribed medication. Patients may be at increased risk of overdose if co- prescribed medications that affect the serum levels of methadone. Equally some prescriptions may increase the metabolism of methadone leading to symptoms of withdrawal. The dose of methadone needs to be adjusted accordingly and the prescriber should be contacted to discuss any concerns. Methadone can prolong the QT interval leading to a rare but potentially fatal condition called Torsades de Pointes. Pharmacists should be aware of the risk of interactions between methadone and other drugs which possess QT interval-prolonging properties or which slow the elimination of methadone. The BNF and Summary Product of Characteristics provide key information on drug interactions. There is also an app (“Drug-drug interactions in opioid therapy”) available for both android and apple devices which gives specific information regarding known drug interactions in patients prescribed methadone or buprenorphine. The app gives useful advice however pharmacists should be aware that it is not fully comprehensive. If an interaction is not included, it does not mean that there is none. Pharmacists should consider that patients may also be prescribed medications for BBVs such as Hepatitis C and HIV through acute services and may be unaware of these. These may impact on ORT and it is worthwhile discussing with patients if they are prescribed any other medication. Xxxx Xxxxx’x University, Liverpool have developed a useful Hepatitis Drug Interaction Tool which can be found at xxxx://xxx.xxx- xxxxxxxxxxxxxxxx.xxx/Xxxxxxxxxxxx.xxxx.
Drug Interactions. For full detail of drug interactions please refer to the current Summary Product Characteristic (SPC) available at xxx.xxxxxxxxx.xxx.xx and the BNF at xxx.xxxxxxxxxxxxxxxxx.xxx Ketamine interacts with theophylline (tachycardia, seizures) and levothyroxine (monitor for hypertension, tachycardia). Diazepam increases the plasma concentration of ketamine. Approved for use by the University Hospitals Drug and Therapeutics Committee – February 2016
