Potential interactions related to the Sevikar HCT combination:
Concomitant use not recommended
Lithium:
Reversible increases in serum lithium concentrations and toxicity have been reported during concomitant administration of lithium with angiotensin converting enzyme inhibitors and, rarely, with angiotensin II receptor antagonists. In addition, renal clearance of lithium is reduced by thiazides and consequently the risk of lithium toxicity may be increased. Therefore use of Sevikar HCT and lithium in combination is not recommended (see section 4.4). If use of the combination proves necessary, careful monitoring of serum lithium levels is recommended.
Concomitant use requiring caution
Baclofen:
Potentiation of antihypertensive effect may occur.
Non-steroidal anti-inflammatory medicinal products:
NSAIDs (i.e. acetylsalicylic acid (> 3 g/day), COX-2 inhibitors and non-selective NSAIDs) may reduce the antihypertensive effect of thiazide diuretics and angiotensin II receptor antagonists.
In some patients with compromised renal function (e. g. dehydrated patients or elderly people with compromised renal function) the co-administration of angiotensin II receptor antagonists and agents that inhibit cyclooxygenase may result in further deterioration of renal function, including possible acute renal failure, which is usually reversible. Therefore, the combination should be administered with caution, especially in the elderly. Patients should be adequately hydrated and consideration should be given to monitoring of renal function after initiation of concomitant therapy and periodically thereafter.
Concomitant use to be taken into account
Amifostine:
Potentiation of antihypertensive effect may occur.
Other antihypertensive agents:
The blood pressure lowering effect of Sevikar HCT can be increased by concomitant use of other antihypertensive medicinal products.
Alcohol, barbiturates, narcotics or antidepressants:
Potentiation of orthostatic hypotension may occur.
Potential interactions related to olmesartan medoxomil:
Concomitant use not recommended
ACE-inhibitors, angiotensin II receptor blockers or aliskiren:
Clinical trial data has shown that dual blockade of the renin-angiotensin-aldosterone-system (RAAS) through the combined use of ACE-inhibitors, angiotensin II receptor blockers or aliskiren is associated with a higher frequency of adverse events such as hypotension, hyperkalaemia and decreased renal function (including acute renal failure) compared to the use of a single RAAS-acting agent (see sections 4.3, 4.4 and 5.1).
Medicinal products affecting potassium levels:
Concomitant use of potassium-sparing diuretics, potassium supplements, salt substitutes containing potassium or other medicinal products that may increase serum potassium levels (e. g. heparin, ACE inhibitors) may lead to increases in serum potassium (see section 4.4). If medicinal products that affect potassium are to be prescribed in combination with Sevikar HCT, monitoring of serum potassium is advised.
Additional information
Bile acid sequestering agent colesevelam:
Concurrent administration of the bile acid sequestering agent colesevelam hydrochloride reduces the systemic exposure and peak plasma concentration of olmesartan and reduces t1/2. Administration of olmesartan medoxomil at least 4 hours prior to colesevelam hydrochloride decreased the drug interaction effect. Administering olmesartan medoxomil at least 4 hours before the colesevelam hydrochloride dose should be considered (see section 5.2).
After treatment with antacid (aluminium magnesium hydroxide), a modest reduction in bioavailability of olmesartan was observed.
Olmesartan medoxomil had no significant effect on the pharmacokinetics or pharmacodynamics of warfarin or the pharmacokinetics of digoxin.
Coadministration of olmesartan medoxomil with pravastatin had no clinically relevant effects on the pharmacokinetics of either component in healthy subjects.
Olmesartan had no clinically relevant inhibitory effects on human cytochrome P450 enzymes 1A1/2, 2A6, 2C8/9, 2C19, 2D6, 2E1 and 3A4 in vitro, and had no or minimal inducing effects on rat cytochrome P450 activities. No clinically relevant interactions between olmesartan and medicinal products metabolised by the above cytochrome P450 enzymes are expected.
Potential interactions related to amlodipine
Concomitant use requiring caution
Effects of other medicinal products on amlodipine
CYP3A4 inhibitors:
Concomitant use of amlodipine with strong or moderate CYP3A4 inhibitors (protease inhibitors, azole antifungals, macrolides like erythromycin or clarithromycin, verapamil or diltiazem) may give rise to significant increase in amlodipine exposure. The clinical translation of these pharmacokinetic variations may be more pronounced in the elderly. There is an increased risk of hypotension. Close observation of patients is recommended and dose adjustment may thus be required.
CYP3A4 inducers:
Upon co-administration of known inducers of the CYP3A4, the plasma concentration of amlodipine may vary. Therefore, blood pressure should be monitored and dose regulation considered both during and after concomitant medication particularly with strong CYP3A4 inducers (e.g. rifampicin, hypericum perforatum).
Administration of amlodipine with grapefruit or grapefruit juice is not recommended as bioavailability may be increased in some patients resulting in increased blood pressure lowering effects.
Dantrolene (infusion): In animals, lethal ventricular fibrillation and cardiovascular collapse are observed in association with hyperkalaemia after administration of verapamil and intravenous dantrolene. Due to risk of hyperkalaemia, it is recommended that the co-administration of calcium channel blockers such as amlodipine be avoided in patients susceptible to malignant hyperthermia and in the management of malignant hyperthermia.
Effects of amlodipine on other medicinal products
The blood pressure-lowering effect of amlodipine adds to the blood pressure-lowering effects of other antihypertensive agents.
In clinical interaction studies, amlodipine did not affect the pharmacokinetics of atorvastatin, digoxin or warfarin.
Simvastatin: Co-administration of multiple doses of 10 mg of amlodipine with 80 mg simvastatin resulted in a 77% increase in exposure to simvastatin compared to simvastatin alone. Limit the dose of simvastatin in patients on amlodipine to 20 mg daily.
Tacrolimus: There is a risk of increased tacrolimus blood levels when co-administered with amlodipine. In order to avoid toxicity of tacrolimus, administration of amlodipine in a patient treated with tacrolimus requires monitoring of tacrolimus blood levels and dose adjustment of tacrolimus when appropriate.
Mechanistic Target of Rapamycin (mTOR) Inhibitors: mTOR inhibitors such as sirolimus, temsirolimus, and everolimus are CYP3A substrates. Amlodipine is a weak CYP3A inhibitor. With concomitant use of mTOR inhibitors, amlodipine may increase exposure of mTOR inhibitors.
Cyclosporine: In a prospective study in renal transplant patients, an average 40% increase in trough cyclosporine levels was observed when used concomitantly with amlodipine. The co-administration of Sevikar HCT with cyclosporine may increase exposure to cyclosporine. Monitor trough cyclosporine levels during concomitant use and cyclosporine dose reductions should be made as necessary.
Potential interactions related to hydrochlorothiazide:
Concomitant use not recommended
Medicinal products affecting potassium levels:
The potassium-depleting effect of hydrochlorothiazide (see section 4.4) may be potentiated by the coadministration of other medicinal products associated with potassium loss and hypokalaemia (e. g. other kaliuretic diuretics, laxatives, corticosteroids, ACTH, amphotericin, carbenoxolone, penicillin G sodium or salicylic acid derivatives). Such concomitant use is therefore not recommended.
Concomitant use requiring caution
Calcium salts:
Thiazide diuretics may increase serum calcium owing to decreased excretion. If calcium supplements must be prescribed, serum calcium should be monitored and calcium dosage adjusted accordingly.
Cholestyramine and colestipol resins:
Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins.
Digitalis glycosides:
Thiazide-induced hypokalaemia or hypomagnesaemia may favour the onset of digitalis-induced cardiac arrhythmias.
Medicinal products affected by serum potassium disturbances:
Periodic monitoring of serum potassium and ECG is recommended when Sevikar HCT is administered with medicinal products affected by serum potassium disturbances (e. g. digitalis glycosides and antiarrhythmics) and with the following torsades de pointes (ventricular tachycardia)-inducing medicinal products (including some antiarrhythmics), hypokalaemia being a predisposing factor to torsades de pointes (ventricular tachycardia):
- Class Ia antiarrhythmics (e. g. quinidine, hydroquinidine, disopyramide).
- Class III antiarrhythmics (e. g. amiodarone, sotalol, dofetilide, ibutilide).
- Some antipsychotics (e. g. thioridazine, chlorpromazine, levomepromazine, trifluoperazine, cyamemazine, sulpiride, sultopride, amisulpride, tiapride, pimozide, haloperidol, droperidol).
- Others (e. g. bepridil, cisapride, diphemanil, erythromycin IV, halofantrin, mizolastin, pentamidine, sparfloxacin, terfenadine, vincamine IV).
Non-depolarizing skeletal muscle relaxants (e. g. tubocurarine):
The effect of nondepolarizing skeletal muscle relaxants may be potentiated by hydrochlorothiazide.
Anticholinergic agents (e. g. atropine, biperiden):
Increase of the bioavailability of thiazide-type diuretics by decreasing gastrointestinal motility and stomach emptying rate.
Antidiabetic medicinal products (oral agents and insulin):
The treatment with a thiazide may influence the glucose tolerance. Dosage adjustment of the antidiabetic medicinal product may be required (see section 4.4).
Metformin:
Metformin should be used with caution because of the risk of lactic acidosis induced by possible functional renal failure linked to hydrochlorothiazide.
Beta-blockers and diazoxide:
The hyperglycaemic effect of beta-blockers and diazoxide may be enhanced by thiazides.
Pressor amines (e. g. noradrenaline):
The effect of pressor amines may be decreased.
Medicinal products used in the treatment of gout (e. g. probenecid, sulfinpyrazone and allopurinol):
Dosage adjustment of uricosuric medicinal products may be necessary since hydrochlorothiazide may raise the level of serum uric acid. Increase in dosage of probenecid or sulfinpyrazone may be necessary. Coadministration of a thiazide may increase the incidence of hypersensitivity reactions to allopurinol.
Amantadine:
Thiazides may increase the risk of adverse effects caused by amantadine.
Cytotoxic agents (e. g. cyclophosphamide, methotrexate):
Thiazides may reduce the renal excretion of cytotoxic medicinal products and potentiate their myelosuppressive effects.
Salicylates:
In case of high dosages of salicylates hydrochlorothiazide may enhance the toxic effect of the salicylates on the central nervous system.
Methyldopa:
There have been isolated reports of haemolytic anaemia occurring with concomitant use of hydrochlorothiazide and methyldopa.
Cyclosporine:
Concomitant treatment with cyclosporine may increase the risk of hyperuricaemia and gout-type complications.
Tetracyclines:
Concomitant administration of tetracyclines and thiazides increases the risk of tetracycline-induced increase in urea. This interaction is probably not applicable to doxycycline.