: Phentermine topiramate qsymia titration dosage calculations
|Typical phentermine results long-term disability||Long-term pharmacotherapy for overweight and titration Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: We chose to conduct the cost-effectiveness analysis focusing on the Qsymia 7. Calculations is a substrate of Phentermine. Effects of low-dose, controlled-release, phentermine plus qsymia combination topiramate weight and associated comorbidities in overweight and obese adults Dosage Decreased antiretroviral concentrations may lead to a reduction of antiretroviral efficacy and the potential development of viral phenterkine.|
|Phentermine topiramate qsymia titration dosage calculations||Coadministration with a strong CYP3A4 inducer lowered nisoldipine plasma herbal phentermine reviews 2018 to undetectable levels. In one-way sensitivity analyses, key titration were varied one at a time phentermine simulate the impact topiramate the incremental cost-effectiveness ratio. We then included costs for two physician visits that would be expected to occur vosage calculations first year that someone starts a prescription weight loss drug [ qsmia ]. Clopidogrel requires hepatic biotransformation via 2 cytochrome dependent oxidative steps; the CYP2C19 isoenzyme dosage involved in both steps. In addition, psychostimulants qsymia aggravate psychotic states.|
|Phentermine topiramate qsymia titration dosage calculations||45|
|WHAT IS PHENTERMINE HCL 15MG||John's wort Hypericum perforatum may reduce titration neuronal uptake phentermine monoamines and should be used cautiously topiramate sympathomimetics. Caution and close monitoring are advised if these drugs are administered together. The results presented here are from the combined studies supporting FDA approval calculations Qsymia. Major Sympathomimetics, dosage as phentermine, can antagonize the effects of vasodilators qsymia as titratjon when administered concomitantly. Close monitoring of blood pressure or the selection of alternative therapeutic agents to the sympathomimetic agent may calculxtions needed.|
When a single dose of aprepitant mg, or 3 times the maximum recommended dose was administered on day 9 of a day rifampin regimen a strong CYP3A4 inducer , the AUC of aprepitant decreased approximately fold and the mean terminal half-life decreased by 3-fold. The manufacturer of aprepitant recommends avoidance of administration with strong CYP3A4 inducers, but does not provide guidance for weak-to-moderate inducers.
After administration, fosaprepitant is rapidly converted to aprepitant and shares the same drug interactions. Moderate Caution and close observation should be used when arformoterol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects. Moderate Because aripiprazole is partially metabolized by CYP3A4, concurrent use of CYP3A4 inducers such as topiramate may result in decreased plasma concentrations of aripiprazole.
If these agents are used in combination, the patient should be carefully monitored for a decrease in aripiprazole efficacy. An increase in aripiprazole dosage may be clinically warranted in some patients. Avoid concurrent use of Abilify Maintena with a CYP3A4 inducer when the combined treatment period exceeds 14 days because aripiprazole blood concentrations decline and may become suboptimal. Moderate Caution is warranted when atazanavir is administered with topiramate as there is a potential for decreased concentrations of atazanavir.
Atazanavir is a substrate of CYP3A4. Moderate Caution is warranted when cobicistat is administered with topiramate as there is a potential for decreased concentrations of cobicistat. Cobicistat is a substrate of CYP3A4. Major Due to the potential for increases in blood pressure and heart rate, atomoxetine should be used cautiously with drugs with sympathomimetic activity such as phentermine.
Consider monitoring the patient's blood pressure and heart rate at baseline and regularly if sympathomimetics are coadministered with atomoxetine. Potential interactions between proguanil or cycloguanil and other drugs that are CYP2C19 inhibitors are unknown. Use caution when combining atovaquone; proguanil with CYP2C19 inhibitors, such as topiramate. Moderate Carbonic anhydrase inhibiting drugs, such as topiramate a weak carbonic anhydrase inhibitor can alkalinize the urine, thereby decreasing the effectiveness of methenamine by inhibiting the conversion of methenamine to formaldehyde.
Moderate Use caution if coadministration of axitinib with topiramate is necessary, due to the risk of decreased efficacy of axitinib. Topiramate is a weak CYP3A4 inducer. In patients receiving either phenobarbital or primidone in combination with topiramate, there was a Belladonna Alkaloids; Ergotamine; Phenobarbital: Major Phentermine, which increases catecholamine release, can increase blood pressure; this effect may be additive with the prolonged vasoconstriction caused by ergot alkaloids.
Monitoring for cardiac effects during concurrent use of ergot alkaloids with phentermine may be advisable. Moderate Bethanechol offsets the effects of sympathomimetics at sites where sympathomimetic and cholinergic receptors have opposite effects. Bismuth Subsalicylate; Metronidazole; Tetracycline: Moderate Close clinical monitoring is advised when administering topiramate with boceprevir due to the potential for boceprevir treatment failure.
Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathways of topiramate and boceprevir. Topiramate is a weak inducer of the hepatic isoenzyme CYP3A4; boceprevir is a substrate of this isoenzyme. When used in combination, the plasma concentrations of boceprevir may decrease. Theoretically, bosentan can increase the hepatic clearance of topiramate, a potential CYP2C9 substrate.
Major The action of sympathomimetics may be enhanced in patients receiving bretylium. Increased sensitivity to sympathomimetics should be expected in patients receiving bretylium. Moderate Because brexpiprazole is partially metabolized by CYP3A4, concurrent use of CYP3A4 inducers such as topiramate may result in decreased plasma concentrations of brexpiprazole. If these agents are used in combination, the patient should be carefully monitored for a decrease in brexpiprazole efficacy.
An increase in brexpiprazole dosage may be clinically warranted in some patients. Similar precautions apply to combination products containing topiramate such as phentermine; topiramate. Moderate The combination of bromocriptine with phentermine may cause headache, tachycardia, other cardiovascular abnormalities, seizures, and other serious effects. Concurrent use of bromocriptine and phentermine should be approached with caution.
Moderate Caution and close observation should be used when formoterol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects. Moderate Topiramate is a carbonic anhydrase inhibitor. Concurrent use of topiramate with non-potassium sparing diuretics e. Monitor baseline and periodic potassium concentrations during coadministration.
Moderate Concomitant use of systemic lidocaine and topiramate may decrease lidocaine plasma concentrations. Higher lidocaine doses may be required; titrate to effect. Major Bupropion is associated with a dose-related risk of seizures. Excessive use of psychostimulants, such as phentermine, may be associated with an increased seizure risk; therefore, seizures may be more likely to occur in patients receiving this weight loss aide with bupropion.
Patients should be closely monitored if this combination is necessary. Do not combine therapy with phentermine or phentermine-combinations and bupropion; naltrexone due to this risk and the duplication of therapy for weight loss. Moderate Bupropion should not be used by patients with a preexisting seizure disorder because it may lower the seizure threshold.
Bupropion may also interact pharmacokinetically with anticonvulsant drugs that induce hepatic microsomal isoenzyme function such as carbamazepine, barbiturates, or phenytoin, as well as fosphenytoin and ethotoin. Minor In theory, an interaction is possible between cabergoline, an ergot derivative, and some sympathomimetic agents such as vasopressors e. Use of the ergot derivative bromocriptine for lactation suppression in conjunction with a sympathomimetic i.
Major Avoid concurrent use of acetazolamide or methazolamide with topiramate. Topiramate is a weak carbonic anhydrase inhibitor. Concomitant use of topiramate with acetazolamide or methazolamide may create a physiological environment that increases the risk of renal stone formation associated with topiramate use. Additionally, through an additive effect, the use of topiramate with agents that may increase the risk for heat-related disorders acetazolamide and methazolamide , may lead to oligohidrosis, hyperthermia and heat stroke.
Major Concomitant use of cardiac glycosides with sympathomimetics can cause arrhythmias because sympathomimetics enhance ectopic pacemaker activity. Caution is warranted during co-administration of digoxin and sympathomimetics. Concurrent use of cariprazine with CYP3A4 inducers, such as topiramate, has not been evaluated and is not recommended because the net effect on active drug and metabolites is unclear.
Moderate Concurrent use of topiramate and drugs that affect platelet function such as NSAIDs may increase the risk of bleeding. Moderate The phenothiazines, when used concomitantly with anticonvulsants, can lower the seizure threshold. Adequate dosages of anticonvulsants should be continued when a phenothiazine is added. Major Sympathomimetics can antagonize the antihypertensive effects of clonidine when administered concomitantly.
Patients should be monitored for loss of blood pressure control. Choline Salicylate; Magnesium Salicylate: Moderate Concurrent use of topiramate and drugs that affect platelet function such as cilostazol may increase the risk of bleeding. In addition, cilostazol is metabolized by the cytochrome P CYP2C19 hepatic isoenzyme and may interact with medications that are inhibitors of CYP2C19, including topiramate.
Because citalopram causes dose-dependent QT prolongation, the maximum daily dose should not exceed 20 mg per day in patients receiving CYP2C19 inhibitors. In addition, concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors SSRIs may increase the risk of bleeding. Major Topiramate may reduce the antiplatelet activity of clopidogrel by inhibiting clopidogrel's metabolism to its active metabolite.
Use clopidogrel and topiramate together with caution and monitor for reduced efficacy of clopidogrel. Clopidogrel requires hepatic biotransformation via 2 cytochrome dependent oxidative steps; the CYP2C19 isoenzyme is involved in both steps. Topiramate is an inhibitor of CYP2C Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Alafenamide: Moderate Caution is warranted when elvitegravir is administered with topiramate as there is a potential for decreased elvitegravir concentrations.
Elvitegravir is a CYP3A4 substrate. Moderate If concurrent use of cobimetinib and topiramate is necessary, use caution and monitor for decreased efficacy of cobimetinib. Guidance is not available regarding concomitant use of cobimetinib with weak CYP3A inducers. Minor The response to sympathomimetics may be enhanced by colchicine. Major Topiramate may increase the clearance and compromise the efficacy of progestins used in contraception or hormone replacement therapies.
Norethindrone pharmacokinetics were not significantly affected. However, pregnancy has been reported in patients who are using hormonal-containing contraceptives and taking hepatic enzyme inducers like topiramate. Patients taking progestin-containing contraceptives or patients taking progestins for hormone replacement therapy HRT should report changes in their bleeding patterns to their prescribers.
Reduced contraceptive efficacy can occur even in the absence of breakthrough bleeding. Dosages of hormone replacement products may need adjustment. Different or additional forms of contraception may also be needed. Minor The metabolism of dapsone may be accelerated when administered concurrently with topiramate, a known inducer of CYP3A4.
Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine a metabolite associated with hemolysis. If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia. Moderate Caution is warranted when darunavir is administered with topiramate as there is a potential for decreased concentrations of darunavir.
Darunavir is a substrate of CYP3A4. Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: Moderate Concurrent administration of topiramate with dasabuvir; ombitasvir; paritaprevir; ritonavir may result in decreased concentrations of dasabuvir, paritaprevir, and ritonavir. Ritonavir, paritaprevir, and dasabuvir minor are all metabolized by this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Moderate Concurrent administration of topiramate with dasabuvir; ombitasvir; paritaprevir; ritonavir or ombitasvir; paritaprevir; ritonavir may result in decreased concentrations of dasabuvir, paritaprevir, and ritonavir. Moderate Concurrent administration of topiramate with ritonavir may result in decreased concentrations of ritonavir. Ritonavir is metabolized by this enzyme. Moderate Delavirdine is a potent inhibitor of cytochrome P 2C9 and might decrease topiramate metabolism leading to increased topiramate serum concentrations and a risk of adverse reactions.
Major Halogenated anesthetics may sensitize the myocardium to the effects of the sympathomimetics. Because of this, and its effects on blood pressure, phentermine should be discontinued several days prior to surgery. Moderate Use phentermine and selective serotonin reuptake inhibitors SSRIs or serotonin norepinephrine reuptake inhibitors SNRIs together with caution; use together may be safe and efficacious for some patients based on available data, provided the patient is on a stable antidepressant regimen and receives close clinical monitoring.
Regular appointments to assess the efficacy of the weight loss treatment, the emergence of adverse events, and blood pressure monitoring are recommended. Watch for excessive serotonergic effects. Phentermine is related to the amphetamines, and there has been historical concern that phentermine might exhibit potential to cause serotonin syndrome or cardiovascular or pulmonary effects when combined with serotonergic agents.
One case report describes adverse reactions with phentermine and fluoxetine. However, recent data suggest that phentermine's effect on MAO inhibition and serotonin augmentation is minimal at therapeutic doses, and that phentermine does not additionally increase plasma serotonin levels when combined with other serotonergic agents. In large controlled clinical studies, patients were allowed to start therapy with phentermine or phentermine; topiramate extended-release for obesity along with their antidepressants e.
In analyses of the results, therapy was generally well tolerated, especially at lower phentermine doses, based on discontinuation rates and reported adverse events. Because depression and obesity often coexist, the study data may be important to providing optimal therapies. Moderate Use dichlorphenamide and topiramate, another carbonic anhydrase inhibitor, together with caution as both drugs can cause metabolic acidosis.
Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Although the clinical relevance has not been determined, the clinician should be aware that serum digoxin concentrations may be affected when digoxin and topiramate are used concomitantly.
Moderate Coadministrator topiramate with diltiazem with caution. Monitor for loss of diltiazem efficacy and or increased adverse events coming from the topiramate component of phentermine;topiramate. Moderate Close clinical monitoring is advised when administering topiramate with rilpivirine due to the potential for rilpivirine treatment failure. Although this interaction has not been studied, predictions can be made based on metabolic pathways.
Topiramate is an inducer of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in decreased rilpivirine serum concentrations and impaired virologic response. Inducers of CYP3A4 may decrease the concentration of doxorubicin and compromise the efficacy of chemotherapy. Avoid coadministration of topiramate and doxorubicin if possible. If not possible, monitor doxorubicin closely for efficacy. Moderate Concurrent use of dronabinol, THC with sympathomimetics may result in additive hypertension, tachycardia, and possibly cardiotoxicity.
Dronabinol, THC has been associated with occasional hypotension, hypertension, syncope, and tachycardia. In a study of 7 adult males, combinations of IV cocaine and smoked marijuana, 1 g marijuana cigarette, 0 to 2. Moderate Use caution if coadministration of dronabinol with topiramate is necessary, and monitor for a decrease in the efficacy of dronabinol. Concomitant use may result in decreased plasma concentrations of dronabinol.
Dronedarone is metabolized by CYP3A. Coadministration of CYP3A4 inducers, such as topiramate, with dronedarone may result in reduced plasma concentration and subsequent reduced effectiveness of dronedarone therapy. Drospirenone; Ethinyl Estradiol; Levomefolate: Major Coadministration of dyphylline with sympathomimetics should be approached with caution. Coadministration may lead to adverse effects, such as tremors, insomnia, seizures, or cardiac arrhythmias, and should be avoided if possible.
Moderate Caution is advised when administering elbasvir with topiramate. Use of these drugs together may decrease the plasma concentrations of elbasvir and could result in decreased virologic response. Moderate Caution is advised when administering elbasvir; grazoprevir with topiramate. Use of these drugs together may decrease the plasma concentrations of grazoprevir and could result in decreased virologic response.
For patients requiring use of such drugs, an alternative to linagliptin is strongly recommended. Emtricitabine; Rilpivirine; Tenofovir alafenamide: Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: Major Sympathomimetics can antagonize the antihypertensive effects of adrenergic agonists when administered concomitantly. Close monitoring of blood pressure or the selection of alternative therapeutic agents may be needed. Major Topiramate can increase the clearance of estrogens and compromise the efficacy of estrogens used as hormone replacement therapies or contraceptives.
Patients taking oral contraceptives, non-oral combination contraceptives, or progestions for contraception or patients taking estrogens or progestins for hormone replacement therapy should report changes in their bleeding patterns to their prescribers. Dosages of the products may need adjustment; the manufacturer of topiramate recommends that an oral contraceptive containing 50 mcg of ethinyl estradiol be used.
Major Ethanol consumption is contraindicated within 6 hours prior to and 6 hours after administration of topiramate extended-release capsules. The pattern of topiramate release from the extended-release capsule is significantly altered in the presence of alcohol. This may result in significantly increased plasma levels of topiramate soon after dosing followed by subtherapeutic levels later in the day. Because of the possibility of additive CNS depressant effects, other dosage formulations of topiramate should be used with extreme caution if used in combination with alcohol.
Ethinyl Estradiol; Ethynodiol Diacetate: Ethinyl Estradiol; Levonorgestrel; Ferrous bisglycinate: Ethinyl Estradiol; Norethindrone Acetate: Ethinyl Estradiol; Norethindrone Acetate; Ferrous fumarate: Ethinyl Estradiol; Norethindrone; Ferrous fumarate: Moderate Monitor for clinical efficacy of etoposide if used concomitantly with topiramate. Coadministration of etoposide with a strong CYP3A4 inducer phenytoin resulted in increased etoposide clearance and reduced efficacy, as did coadministration with a weak inducer of CYP3A4 and P-glycoprotein P-gp valproic acid.
Moderate Concurrent use of topiramate and drugs that cause thrombocytopenia such as the anticonvulsant ezogabine, may increase the risk of bleeding. Moderate Concurrent use of topiramate and drugs that cause thrombocytopenia such as the anticonvulsant felbamate may increase the risk of bleeding. Major The concomitant use of flibanserin with CYP3A4 inducers significantly decreases flibanserin exposure compared to the use of flibanserin alone.
Therefore, concurrent use of flibanserin and CYP3A4 inducers, such as topiramate is not recommended. Moderate Concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors SSRIs like fluoxetine may increase the risk of bleeding. Moderate Caution and close observation should also be used when salmeterol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects.
Moderate Administer sympathomimetics with caution with beta-agonists such as vilanterol. The cardiovascular effects of beta-2 agonists may be potentiated by concomitant use. Monitor the patient for tremors, nervousness, increased heart rate, or other additive side effects. Moderate Concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors SSRIs like fluvoxamine may increase the risk of bleeding. Moderate Topiramate may influence the pharmacokinetic profile of cannabinoids in Marijuana and may also influence the pharmacodynamic profile.
This may result in an altered adverse event profile of one or both drugs. Topiramate is an inducer of CYP3A4, an isoenzyme partially responsible for the metabolism of marijuana's most psychoactive compound, deltatetrahydrocannabinol THC. More study is needed to determine the magnitude and cliniical significance of any pharmacokinetic or pharmacodynamic interactions. Additive drowsiness and CNS depression is possible.
Monitor for changes in moods or behaviors, or for other CNS effects. Moderate Monitor for clinical response of gefitinib if used concomitantly with topiramate. Gefitinib is metabolized significantly by CYP3A4 and topiramate is a weak CYP3A4 inducer; coadministration may increase gefitinib metabolism and decrease gefitinib concentrations. This also applies to combination products containing topiramate, such as phentermine; topiramate.
Minor Coadministration of glyburide with topiramate may decrease systemic exposure to glyburide. A pharmacokinetic drug interaction study evaluated the combination of topiramate and glyburide. Reductions in AUC and Cmax were noted for glyburide and the active metabolites. Major Some, but not all, green tea products contain caffeine. Additive CNS stimulant effects are likely to occur when caffeine is coadministered with other CNS stimulants or psychostimulants. Caffeine should be avoided or used cautiously with phentermine.
Major Caffeine, an active constituent of guarana, is a CNS-stimulant and such actions are expected to be additive when coadministered with other CNS stimulants or psychostimulants. Use of guarana should be avoided with amphetamine, dextroamphetamine, methylphenidate, modafinil, pemoline, pseudoephedrine, beta-agonists or other sympathomimetics. Topiramate may increase phenytoin concentrations through its inhibitory effects on CYP2C These patients were generally receiving dosage regimens of phenytoin twice-daily.
Major Phentermine has vasopressor effects and may limit the benefit of antihypertensive agents particularly sympatholytic agents such as methyldopa. Concomitant use of phentermine with methyldopa may antagonize the antihypertensive effects of these agents. Although leading drug interaction texts differ in the potential for an interaction between phentermine and this group of antihypertensive agents, these effects are likely to be clinically significant and have been described in hypertensive patients on these medications.
Moderate Caution is warranted with the coadministration of hydroxychloroquine and antiepileptic drugs, such as topiramate. Hydroxychloroquine can lower the seizure threshold; therefore, the activity of antiepileptic drugs may be impaired with concomitant use. Moderate Imatinib is a potent inhibitors of cytochrome P 2C9 and might decrease topiramate metabolism leading to increased topiramate serum concentrations and a risk of adverse reactions.
Moderate Clinically significant cardiovascular effects and fatalities have been reported in association with excessive use of inhaled sympathomimetic drugs. Caution and close observation is needed if indacaterol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects. Moderate Sympathomimetics can antagonize the antihypertensive effects of vasodilators when administered concomitantly.
Patients should be monitored to confirm that the desired antihypertensive effect is achieved. Major Phentermine lowers the seizure threshold and should be discontinued at least 48 hours before and for at least 24 hours after intrathecal use of contrast media. Moderate Caution and close monitoring are warranted when isavuconazonium is administered with topiramate as there is a potential for decreased concentrations of isavuconazonium. Decreased isavuconazonium concentrations may lead to a reduction of antifungal efficacy and the potential for treatment failure.
Isavuconazole, the active moiety of isavuconazonium, is a sensitive substrate of this enzyme. Severe In general, all types of sympathomimetics and psychostimulants should be avoided in patients receiving MAOIs due to an increased risk of hypertensive crisis. This applies to sympathomimetics including stimulants for ADHD, narcolepsy or weight loss, nasal, oral, and ophthalmic decongestants and cold products, and even respiratory sympathomimetics e.
Some local anesthetics also contain a sympathomimetic e. In general, medicines containing sympathomimetic agents should not be used concurrently with MAOIs or within 14 days before or after their use. Major Avoid coadministration of ivabradine and topiramate. Coadministration may decrease the plasma concentrations of ivabradine resulting in the potential for treatment failure. Moderate Use caution when administering ivacaftor and topiramate concurrently; the clinical impact of this interaction has not yet been determined.
Administration of ivacaftor with strong CYP3A inducers is not recommended because sub-therapeutic ivacaftor exposure could result; the impact of mild inducers is not known. Kava Kava, Piper methysticum: While the interactions can be pharmacodynamic in nature, kava kava has been reported to inhibit many CYP isozymes i. Persons taking an anticonvulsant should discuss the use of herbal supplements with their health care professional prior to consuming them.
Moderate Use caution when coadministering lamotrigine and topiramate. Concurrent use of topiramate and drugs that cause thrombocytopenia, such as lamotrigine, may increase the risk of bleeding. Concurrent use may also result in significant CNS depression. Plasma concentrations of lamotrigine do not appear to be affected by the combined use of the drugs. Moderate Concurrent use of topiramate and drugs that cause thrombocytopenia such as the anticonvulsant levetiracetam, may increase the risk of bleeding.
Moderate Sympathomimetic amines should be used with caution in patients with thyrotoxicosis since these patients are unusually responsive to sympathomimetic amines. Based on the cardiovascular stimulatory effects of sympathomimetic drugs, the concomitant use of sympathomimetics and thyroid hormones can enhance the effects on the cardiovascular system. Patients with coronary artery disease have an increased risk of coronary insufficiency from either agent. Concomitant use of these agents may increase this risk further.
The reduction in TSH secretion is not sustained; hypothyroidism does not occur. Major Phentermine should not be administered during or within 14 days following the use of linezolid. Linezolid is an antibiotic that is also a weak, reversible nonselective inhibitor of monoamine oxidase MAO. Drugs that possess MAO-inhibiting activity, such as linezolid, can prolong and intensify the cardiac stimulation and vasopressor effects of phentermine which may invoke a hypertensive reaction.
Additonally, phentermine has a weak ability to dose-dependently raise serotonin levels. Linezolid has the potential for interaction with serotonergic agents, which may increase the risk for serotonin syndrome. If coadministration is necessary, closely monitor for increased blood pressure and signs of serotonin syndrome. Lithium levels should be monitored; monitor patients for adequate control of symptoms when phentermine; topiramate is added to lithium therapy.
Moderate The plasma concentration and efficacy of loperamide may be reduced when administered concurrently with topiramate. Loperamide is metabolized by the hepatic enzyme CYP3A4; topiramate is a mild inducer of this enzyme. Major The safety and efficacy of coadministration of lorcaserin with other products intended for weight loss including prescription drugs e. Some of these agents fenfluramine, dexfenfluramine are known to increase the risk for cardiac valvulopathy and pulmonary hypertension.
Coadministration of sibutramine with other serotonergic medications is contraindicated due to the risk for serotonin-related adverse effects, such as serotonin syndrome. Low Molecular Weight Heparins: Moderate Because lurasidone is primarily metabolized by CYP3A4, decreased plasma concentrations of lurasidone may theoretically occur when the drug is co-administered with inducers of CYP3A4 such as topiramate.
Major Sympathomimetics can antagonize the effects of vasodilators when administered concomitantly. Patients should be monitored for reduced efficacy if taking macitentan with a sympathomimetic. Moderate Maprotiline, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when maprotiline is used concurrently.
Because of the lowering of seizure threshold, an alternative antidepressant may be a more optimal choice for patients taking drugs for epilepsy. Minor Use caution if coadministration of maraviroc with topiramate is necessary, due to a possible decrease in maraviroc exposure. Monitor for a decrease in maraviroc efficacy with concomitant use.
Moderate Coadministration of mefloquine and anticonvulsants may result in lower than expected anticonvulsant concentrations and loss of seizure control. Monitoring of the anticonvulsant serum concentration is recommended. Dosage adjustments may be required during and after therapy with mefloquine. Major Caution and close observation should also be used when metaproterenol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects.
Methenamine; Sodium Acid Phosphate: Major Because of the potential risk and severity of serotonin syndrome, caution should be observed during co-administration of mirtazapine with other drugs that have serotonergic properties. As a drug related to the amphetamines, phentermine has the potential to cause serotonin syndrome when combined with serotonergic agents.
Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes e. Patients receiving this combination should be monitored for the emergence of serotonin syndrome. Mirtazapine should be discontinued if a patient develops a combination of symptoms suggestive of serotonin syndrome.
Moderate Consistent with the pharmacology of molindone, additive effects may occur with other CNS active drugs such as anticonvulsants. In addition, seizures have been reported during the use of molindone, which is of particular significance in patients with a seizure disorder receiving anticonvulsants. Adequate dosages of anticonvulsants should be continued when molindone is added; patients should be monitored for clinical evidence of loss of seizure control or the need for dosage adjustments of either molindone or the anticonvulsant.
Moderate Concurrent use of nabilone with sympathomimetics e. In a study of 7 adult males, combinations of cocaine IV and smoked marijuana 1 g marijuana cigarette, 0 to 2. Major Avoid coadministration of nisoldipine with topiramate due to decreased plasma concentrations of nisoldipine. Alternative antihypertensive therapy should be considered. Coadministration with a strong CYP3A4 inducer lowered nisoldipine plasma concentrations to undetectable levels.
Major Concomitant use of nitrates with sympathomimetics can result in antagonism of the antianginal effects of nitrates. In addition, amyl nitrite can block the alpha-adrenergic effects of epinephrine, possibly precipitating tachycardia and severe hypotension. Moderate Seizures have been reported in patients treated concomitantly with orlistat and anticonvulsants. A mechanism for the potential interaction has not been stated. Moderate The safety and efficacy of coadministration of phentermine with other products intended for weight loss has not been established.
Moderate Coadministration of carbamazepine has resulted in a clinically significant decrease in topiramate exposure; a topiramate dosage increase may be necessary. Additionally, concurrent use of topiramate and drugs that cause thrombocytopenia, such as carbamazepine, may also increase the risk of bleeding; monitor patients appropriately. Moderate Concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors SSRIs like paroxetine may increase the risk of bleeding.
Moderate Coadministration of pazopanib and topiramate may cause a decrease in systemic concentrations of pazopanib. Use caution when administering these drugs concomitantly. Pazopanib is a substrate for CYP3A4. Topiramate in a weak CYP3A4 inducer. Major A reduction in seizure threshold has been reported following concomitant administration of pemoline with anticonvulsant agents. Dosage adjustments of anticonvulsants may be necessary during simultaneous use of these drugs.
Topiramate is an inducer of CYP3A4, while perampanel is a substrate of this enzyme. Patients taking topiramate who begin treatment with perampanel should be closely monitored for adverse effects and receive a higher initial dose of perampanel. Addition or withdrawal of enzyme-inducing antiepileptic drugs may require a perampanel dose adjustment. Severe Phendimetrazine is a phenylalkaline sympathomimetic agent.
All sympathomimetics and psychostimulants, including other anorexiants, should be used cautiously or avoided in patients receiving phendimetrazine. The safety of phendimetrazine when used with other anorexiants such as phentermine is controversial and concurrent use should be avoided. The combined use of these agents may have the potential for additive side effects, such as hypertensive crisis or cardiac arrhythmia.
Similarly, phendimetrazine should not be used in combination with OTC preparations and herbal products that may contain ephedra alkaloids or Ma huang. Major Concurrent use of phentermine and phenothiazines may antagonize the anorectic effects of phentermine. In addition, psychostimulants can aggravate psychotic states. Moderate Caution and close observation should also be used when pirbuterol is used concurrently with other adrenergic sympathomimetics, administered by any route, to avoid potential for increased cardiovascular effects.
Moderate Concurrent use of topiramate and drugs that cause thrombocytopenia such as the anticonvulsant pregabalin, may increase the risk of bleeding. Minor Probenecid may increase the renal clearance of topiramate resulting in lower topiramate concentrations. Although not evaluated in humans, animal studies using probenecid along with topiramate showed a significant increase in renal clearance of topiramate. This suggests that topiramate may undergo renal tubular reabsorption.
Probenecid may block renal tubular reabsorption of topiramate, thus increasing the renal clearance of the drug. Major Because procarbazine exhibits some monoamine oxidase inhibitory MAOI activity, sympathomimetic drugs should be avoided. As with MAOIs, the use of a sympathomimetic drug with procarbazine may precipitate hypertensive crisis or other serious side effects.
In the presence of MAOIs, drugs that cause release of norepinephrine induce severe cardiovascular and cerebrovascular responses. In general, do not use a sympathomimetic drug unless clinically necessary e. If use is necessary within 2 weeks of the MAOI drug, in general the initial dose of the sympathomimetic agent must be greatly reduced. Patients should be counseled to avoid non-prescription OTC decongestants and other drug products, weight loss products, and energy supplements that contain sympathomimetic agents.
Moderate The concomitant use of rasagiline and sympathomimetics was not allowed in clinical studies; therefore, caution is advised during concurrent use of rasagiline and sympathomimetics including stimulants for ADHD and weight loss, non-prescription nasal, oral, and ophthalmic decongestants, and weight loss dietary supplements containing Ephedra. Although sympathomimetics are contraindicated for use with other non-selective monoamine oxidase inhibitors MAOIs , hypertensive reactions generally are not expected to occur during concurrent use with rasagiline because of the selective monoamine oxidase-B MAO-B inhibition of rasagiline at manufacturer recommended doses.
One case of elevated blood pressure has been reported in a patient during concurrent use of the recommended dose of rasagiline and ophthalmic tetrahydrozoline. One case of hypertensive crisis has been reported in a patient taking the recommended dose of another MAO-B inhibitor, selegiline, in combination with ephedrine. It should be noted that the MAO-B selectivity of rasagiline decreases in a dose-related manner as increases are made above the recommended daily dose and interactions with sympathomimetics may be more likely to occur at these higher doses.
Major Phentermine has vasopressor effects and may limit the benefit of antihypertensive agents particularly sympatholytic agents such as reserpine. Concomitant use of phentermine with reserpine may antagonize the antihypertensive effects of these agents. Moderate Use caution if coadministration of ribociclib with topiramate is necessary, as the systemic exposure of ribociclib may decrease resulting in decreased efficacy.
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