Quinapril and hydrochlorothiazide

Serious side effects have been reported with quinapril and hydrochlorothiazide. See the "Quinapril and hydrochlorothiazide Precautions" section. 

Common side effects of quinapril and hydrochlorothiazide include the following:

• headache
• dizziness
• coughing
• tiredness (fatigue)
• muscle pain
• viral infection
• stuffy nose (rhinitis)
• nausea and/or vomiting
• stomach (abdominal) pain
• back pain
• diarrhea
• infection that affects the nose, throat, and airways (upper respiratory infection)
• difficulty sleeping (insomnia)
• sleepiness (somnolence)
• Inflammation of the airway which carries air to and from the lungs (bronchitis)
• indigestion
• abnormal physical weakness or lack of energy (asthenia)
• widening of blood vessels (vasodilation)
• feeling like your surroundings are spinning (vertigo)
• chest pain

This is not a complete list of quinapril and hydrochlorothiazide side effects. Ask your doctor or pharmacist for more information. 

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088. 

Tell your doctor about all the medicines you take including prescription and nonprescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you are taking:

• certain medications that also lower blood pressure such as angiotensin-­converting enzyme (ACE) inhibitors like enalapril (Vasotec, Vaseretic) and angiotensin receptor II blockers (ARBs) like valsartan (Diovan)
• aliskiren (Tekturna)
• potassium supplements or potassium-containing salt substitutes
• potassium­ sparing diuretics such as spironolactone (Aldactone), triamterene (Dyrenium), and amiloride (Midamor)
• lithium (Lithobid)
• antibiotics in the tetracycline class tetracycline (Diabecline), doxycycline (Doryx, Oracea), and minocycline (Solodyn)
• injectable gold (sodium aurothiomalate)
• nonsteroidal anti-inflammatory drugs (NSAIDS) such as naproxen (Aleve) and ibuprofen (Advil)
• mTOR inhibitors such as everolimus (Afinitor) and temsirolimus (Torisel)
• digoxin (Lanoxin)
• alcohol, a class of drugs called barbiturates, or a type of pain medications called narcotics
• diabetic medications
• cholestyramine (Questran) and colestipol (Colestid)
• medicines that provide relief for inflamed areas of the body (corticosteroids) such as methylprednisolone (Medrol) and dexamethasone (Decadron)
• substances that raise blood pressure (pressor amines) such as norepinephrine (Levophed)
• medicines that relax skeletal muscles such as cyclobenzaprine (Flexeril) and carisoprodol (Soma)

Do not drink alcohol while on this medication.

This is not a complete list of quinapril and hydrochlorothiazide drug interactions. Ask your doctor or pharmacist for more information. 

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of quinapril and hydrochlorothiazide, salt substitutes containing potassium should be avoided. 

WARNING: FETAL TOXICITY

• When pregnancy is detected, discontinue quinapril and hydrochlorothiazide as soon as possible.
• Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. 

Quinapril HCl/hydrochlorothiazide tablets are fixed-combination tablets that combine an angiotensin-converting enzyme (ACE) inhibitor, quinapril hydrochloride, and a thiazide diuretic, hydrochlorothiazide.

Quinapril hydrochloride is chemically described as [3S-[2[R*(R*)], 3R*]]-2-[2-[[1-(ethoxycarbonyl)-3-phenylpropyl] amino]-1-oxopropyl]-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic acid, monohydrochloride. Its empirical formula is C25H30N2O5. HCl and its structural formula is:

Quinapril hydrochloride is a white to off-white amorphous powder that is freely soluble in aqueous solvents.

Hydrochlorothiazide is chemically described as: 6-Chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its empirical formula is C7H8ClN3O4S2 and its structural formula is:

Hydrochlorothiazide is a white to off-white, crystalline powder which is slightly soluble in water but freely soluble in sodium hydroxide solution.

Quinapril HCl/hydrochlorothiazide tablets are available for oral use as fixed combination tablets in three strengths of quinapril with hydrochlorothiazide: 10 mg with 12.5 mg (quinapril HCl/hydrochlorothiazide tablets 10/12.5), 20 mg with 12.5 mg (quinapril HCl/hydrochlorothiazide tablets 20/12.5), and 20 mg with 25 mg (quinapril HCl/hydrochlorothiazide tablets 20/25). Inactive ingredients: candelilla wax, crospovidone, hydroxypropyl cellulose, hypromellose, iron oxide red, iron oxide yellow, lactose, magnesium carbonate, magnesium stearate, polyethylene glycol, povidone, and titanium dioxide.

No specific information is available on the treatment of overdosage with quinapril HCl/hydrochlorothiazide tablets or quinapril monotherapy; treatment should be symptomatic and supportive. Therapy with quinapril HCl/hydrochlorothiazide tablets should be discontinued, and the patient should be observed. Dehydration, electrolyte imbalance, and hypotension should be treated by established procedures.

The oral median lethal dose of quinapril/hydrochlorothiazide in combination ranges from 1063/664 to 4640/2896 mg/kg in mice and rats. Doses of 1440 to 4280 mg/kg of quinapril cause significant lethality in mice and rats. In single-dose studies of hydrochlorothiazide, most rats survived doses up to 2.75 g/kg.

Data from human overdoses of ACE inhibitors are scanty; the most likely manifestation of human quinapril overdosage is hypotension. In human hydrochlorothiazide overdose, the most common signs and symptoms observed have been those of dehydration and electrolyte depletion (hypokalemia, hypochloremia, hyponatremia). If digitalis has also been administered, hypokalemia may accentuate cardiac arrhythmias.

Laboratory determinations of serum levels of quinapril and its metabolites are not widely available, and such determinations have, in any event, no established role in the management of quinapril overdose.

No data are available to suggest physiological maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of quinapril and its metabolites. Hemodialysis and peritoneal dialysis have little effect on the elimination of quinapril and quinaprilat.

Angiotensin II could presumably serve as a specific antagonist-antidote in the setting of quinapril overdose, but angiotensin II is essentially unavailable outside of scattered research facilities. Because the hypotensive effect of quinapril is achieved through vasodilation and effective hypovolemia, it is reasonable to treat quinapril overdose by infusion of normal saline solution.

(KWIN a pril & hye droe klor oh THYE a zide)

• Hydrochlorothiazide and Quinapril
• Quinapril/Hydrochlorothiazide
• Quinaretic

Quinapril: Prevents conversion of angiotensin I to angiotensin II, resulting in lower levels of angiotensin II, which causes an increase in plasma renin activity and a reduction in aldosterone secretion. A CNS mechanism may also be involved in hypotensive effect as angiotensin II increases adrenergic outflow from CNS. Vasoactive kallikreins may be decreased in conversion to active hormones by ACE inhibitors, thus reducing blood pressure.

Hydrochlorothiazide: Inhibits sodium reabsorption in the distal tubules, causing increased excretion of sodium and water as well as potassium and hydrogen ions.

ACE Inhibitors: Thiazide and Thiazide-Like Diuretics may enhance the hypotensive effect of ACE Inhibitors. Thiazide and Thiazide-Like Diuretics may enhance the nephrotoxic effect of ACE Inhibitors. Monitor therapy

Ajmaline: Sulfonamides may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy

Alcohol (Ethyl): May enhance the orthostatic hypotensive effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Aliskiren: May enhance the hyperkalemic effect of ACE Inhibitors. Aliskiren may enhance the hypotensive effect of ACE Inhibitors. Aliskiren may enhance the nephrotoxic effect of ACE Inhibitors. Management: Aliskiren use with ACEIs or ARBs in patients with diabetes is contraindicated. Combined use in other patients should be avoided, particularly when CrCl is less than 60 mL/min. If combined, monitor potassium, creatinine, and blood pressure closely. Consider therapy modification

Allopurinol: ACE Inhibitors may enhance the potential for allergic or hypersensitivity reactions to Allopurinol. Consider therapy modification

Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, blood pressure lowering medications should be withheld for 24 hours prior to amifostine administration. If blood pressure lowering therapy cannot be withheld, amifostine should not be administered. Consider therapy modification

Aminolevulinic Acid (Systemic): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Systemic). Avoid combination

Aminolevulinic Acid (Topical): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Topical). Monitor therapy

Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Analgesics (Opioid): May enhance the adverse/toxic effect of Diuretics. Analgesics (Opioid) may diminish the therapeutic effect of Diuretics. Monitor therapy

Angiotensin II Receptor Blockers: May enhance the adverse/toxic effect of ACE Inhibitors. Angiotensin II Receptor Blockers may increase the serum concentration of ACE Inhibitors. Management: In US labeling, use of telmisartan and ramipril is not recommended. It is not clear if any other combination of an ACE inhibitor and an ARB would be any safer. Consider alternatives to the combination when possible. Consider therapy modification

Anticholinergic Agents: May increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Antidiabetic Agents: Thiazide and Thiazide-Like Diuretics may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Monitor therapy

Aprotinin: May diminish the antihypertensive effect of ACE Inhibitors. Monitor therapy

AzaTHIOprine: ACE Inhibitors may enhance the myelosuppressive effect of AzaTHIOprine. Monitor therapy

Barbiturates: May enhance the orthostatic hypotensive effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Benazepril: HydroCHLOROthiazide may enhance the hypotensive effect of Benazepril. HydroCHLOROthiazide may enhance the nephrotoxic effect of Benazepril. Benazepril may decrease the serum concentration of HydroCHLOROthiazide. Monitor therapy

Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Beta2-Agonists: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Bile Acid Sequestrants: May decrease the absorption of Thiazide and Thiazide-Like Diuretics. The diuretic response is likewise decreased. Consider therapy modification

Brigatinib: May diminish the antihypertensive effect of Antihypertensive Agents. Brigatinib may enhance the bradycardic effect of Antihypertensive Agents. Monitor therapy

Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Calcium Salts: Thiazide and Thiazide-Like Diuretics may decrease the excretion of Calcium Salts. Continued concomitant use can also result in metabolic alkalosis. Monitor therapy

Canagliflozin: May enhance the hyperkalemic effect of ACE Inhibitors. Canagliflozin may enhance the hypotensive effect of ACE Inhibitors. Monitor therapy

CarBAMazepine: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of CarBAMazepine. Specifically, there may be an increased risk for hyponatremia. Monitor therapy

Cardiac Glycosides: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Cardiac Glycosides. Specifically, cardiac glycoside toxicity may be enhanced by the hypokalemic and hypomagnesemic effect of thiazide diuretics. Monitor therapy

Corticosteroids (Orally Inhaled): May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Corticosteroids (Systemic): May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Cyclophosphamide: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Cyclophosphamide. Specifically, granulocytopenia may be enhanced. Monitor therapy

Dapoxetine: May enhance the orthostatic hypotensive effect of ACE Inhibitors. Monitor therapy

Dexketoprofen: May enhance the adverse/toxic effect of Sulfonamides. Monitor therapy

Diacerein: May enhance the therapeutic effect of Diuretics. Specifically, the risk for dehydration or hypokalemia may be increased. Monitor therapy

Diazoxide: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Diazoxide. Monitor therapy

Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Dofetilide: Thiazide and Thiazide-Like Diuretics may enhance the QTc-prolonging effect of Dofetilide. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Dofetilide. Avoid combination

DPP-IV Inhibitors: May enhance the adverse/toxic effect of ACE Inhibitors. Specifically, the risk of angioedema may be increased. Monitor therapy

Drospirenone: ACE Inhibitors may enhance the hyperkalemic effect of Drospirenone. Monitor therapy

DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Monitor therapy

Eplerenone: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Everolimus: May enhance the adverse/toxic effect of ACE Inhibitors. Specifically, the risk of angioedema may be increased. Monitor therapy

Ferric Gluconate: ACE Inhibitors may enhance the adverse/toxic effect of Ferric Gluconate. Monitor therapy

Ferric Hydroxide Polymaltose Complex: ACE Inhibitors may enhance the adverse/toxic effect of Ferric Hydroxide Polymaltose Complex. Specifically, the risk for angioedema or allergic reactions may be increased. Monitor therapy

Gold Sodium Thiomalate: ACE Inhibitors may enhance the adverse/toxic effect of Gold Sodium Thiomalate. An increased risk of nitritoid reactions has been appreciated. Monitor therapy

Grass Pollen Allergen Extract (5 Grass Extract): ACE Inhibitors may enhance the adverse/toxic effect of Grass Pollen Allergen Extract (5 Grass Extract). Specifically, ACE inhibitors may increase the risk of severe allergic reaction to Grass Pollen Allergen Extract (5 Grass Extract). Consider therapy modification

Heparin: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Heparin (Low Molecular Weight): May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Herbs (Hypotensive Properties): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Monitor therapy

Icatibant: May diminish the antihypertensive effect of ACE Inhibitors. Monitor therapy

Ipragliflozin: May enhance the adverse/toxic effect of Thiazide and Thiazide-Like Diuretics. Specifically, the risk for intravascular volume depletion may be increased. Monitor therapy

Iron Dextran Complex: ACE Inhibitors may enhance the adverse/toxic effect of Iron Dextran Complex. Specifically, patients receiving an ACE inhibitor may be at an increased risk for anaphylactic-type reactions. Management: Follow iron dextran recommendations closely regarding both having resuscitation equipment and trained personnel on-hand prior to iron dextran administration and the use of a test dose prior to the first therapeutic dose. Consider therapy modification

Ivabradine: Thiazide and Thiazide-Like Diuretics may enhance the arrhythmogenic effect of Ivabradine. Monitor therapy

Lanthanum: May decrease the serum concentration of ACE Inhibitors. Management: Administer angiotensin-converting enzyme inhibitors at least two hours before or after lanthanum. Consider therapy modification

Levodopa: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa. Monitor therapy

Levosulpiride: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of Levosulpiride. Avoid combination

Licorice: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Lithium: Thiazide and Thiazide-Like Diuretics may decrease the excretion of Lithium. Consider therapy modification

Lithium: ACE Inhibitors may increase the serum concentration of Lithium. Management: Lithium dosage reductions will likely be needed following the addition of an ACE inhibitor. Monitor patient response to lithium closely following addition or discontinuation of concurrent ACE inhibitor treatment. Consider therapy modification

Loop Diuretics: May enhance the hypotensive effect of ACE Inhibitors. Loop Diuretics may enhance the nephrotoxic effect of ACE Inhibitors. Monitor therapy

Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Mecamylamine: Sulfonamides may enhance the adverse/toxic effect of Mecamylamine. Avoid combination

Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Multivitamins/Fluoride (with ADE): May enhance the hypercalcemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Multivitamins/Minerals (with ADEK, Folate, Iron): Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Multivitamins/Minerals (with ADEK, Folate, Iron). Monitor therapy

Multivitamins/Minerals (with AE, No Iron): Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Multivitamins/Minerals (with AE, No Iron). Specifically, thiazide diuretics may decrease the excretion of calcium, and continued concomitant use can also result in metabolic alkalosis. Monitor therapy

Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicorandil: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: ACE Inhibitors may enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the combination may result in a significant decrease in renal function. Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of ACE Inhibitors. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: Thiazide and Thiazide-Like Diuretics may enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Consider therapy modification

OXcarbazepine: Thiazide and Thiazide-Like Diuretics may enhance the adverse/toxic effect of OXcarbazepine. Specifically, there may be an increased risk for hyponatremia. Monitor therapy

Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Porfimer: Photosensitizing Agents may enhance the photosensitizing effect of Porfimer. Monitor therapy

Potassium Salts: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Potassium-Sparing Diuretics: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Pregabalin: ACE Inhibitors may enhance the adverse/toxic effect of Pregabalin. Specifically, the risk of angioedema may be increased. Monitor therapy

Promazine: Thiazide and Thiazide-Like Diuretics may enhance the QTc-prolonging effect of Promazine. Avoid combination

Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Quinolone Antibiotics: Quinapril may decrease the serum concentration of Quinolone Antibiotics. Management: Separate doses of quinapril and oral quinolones by at least 2 hours in order to reduce the risk of interaction. Monitor for reduced efficacy of the quinolone if these products are used concomitantly. Exceptions: LevoFLOXacin (Oral Inhalation). Consider therapy modification

Reboxetine: May enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Sacubitril: ACE Inhibitors may enhance the adverse/toxic effect of Sacubitril. Specifically, the risk of angioedema may be increased with this combination. Avoid combination

Salicylates: May enhance the nephrotoxic effect of ACE Inhibitors. Salicylates may diminish the therapeutic effect of ACE Inhibitors. Monitor therapy

Selective Serotonin Reuptake Inhibitors: May enhance the hyponatremic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Sirolimus: May enhance the adverse/toxic effect of ACE Inhibitors. Monitor therapy

Sodium Phosphates: ACE Inhibitors may enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with ACEIs, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, maintain adequate hydration and monitor renal function closely. Consider therapy modification

Sodium Phosphates: Diuretics may enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with diuretics, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, hydrate adequately and monitor fluid and renal status. Consider therapy modification

Temsirolimus: May enhance the adverse/toxic effect of ACE Inhibitors. Monitor therapy

Tetracycline Derivatives: Quinapril may decrease the serum concentration of Tetracycline Derivatives. Management: Separate doses of quinapril and oral tetracycline derivatives by at least 2 hours in order to reduce the risk of interaction. Monitor for reduced efficacy of the tetracycline if these products are used concomitantly. Consider therapy modification

Thiazide and Thiazide-Like Diuretics: May enhance the hypotensive effect of ACE Inhibitors. Thiazide and Thiazide-Like Diuretics may enhance the nephrotoxic effect of ACE Inhibitors. Monitor therapy

TiZANidine: May enhance the hypotensive effect of ACE Inhibitors. Monitor therapy

Tolvaptan: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Topiramate: Thiazide and Thiazide-Like Diuretics may enhance the hypokalemic effect of Topiramate. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Topiramate. Management: Monitor for increased topiramate levels/adverse effects (e.g., hypokalemia) with initiation/dose increase of a thiazide diuretic. Closely monitor serum potassium concentrations with concomitant therapy. Topiramate dose reductions may be necessary. Consider therapy modification

Toremifene: Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Toremifene. Monitor therapy

Trimethoprim: May enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Verteporfin: Photosensitizing Agents may enhance the photosensitizing effect of Verteporfin. Monitor therapy

Vitamin D Analogs: Thiazide and Thiazide-Like Diuretics may enhance the hypercalcemic effect of Vitamin D Analogs. Monitor therapy

Yohimbine: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy