Clonidine and Chlorthalidone

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet:

0.1: Clonidine hydrochloride 0.1 mg and chlorthalidone 15 mg [DSC]

0.2: Clonidine hydrochloride 0.2 mg and chlorthalidone 15 mg [DSC]

0.3: Clonidine hydrochloride 0.3 mg and chlorthalidone 15 mg [DSC]

Use: Labeled Indications

Treatment of hypertension

Contraindications

Hypersensitivity to chlorthalidone or other sulfonamide-derived drugs

Note: Although the FDA approved product labeling states this medication is contraindicated with other sulfonamide-containing drug classes, the scientific basis of this statement has been challenged. See “Warnings/Precautions” for more detail.

Dosage and Administration

Dosing: Adult

Hypertension: Oral: One tablet (clonidine 0.1 to 0.3 mg/chlorthalidone 15 mg per tablet) 1 to 2 times daily; maximum: 0.6 mg clonidine and 30 mg chlorthalidone daily

Dosing: Geriatric

May benefit from lower initial dose; see individual agents.

Storage

Store at 20°C to 25°C (68°F to 77°F). Avoid excessive humidity.

Drug Interactions

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

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). 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

Alizapride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Allopurinol: Thiazide and Thiazide-Like Diuretics may enhance the potential for allergic or hypersensitivity reactions to Allopurinol. Thiazide and Thiazide-Like Diuretics may increase the serum concentration of Allopurinol. Specifically, Thiazide Diuretics may increase the concentration of Oxypurinol, an active metabolite of Allopurinol. Monitor therapy

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

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

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

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

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

Beta-Blockers: Alpha2-Agonists may enhance the AV-blocking effect of Beta-Blockers. Sinus node dysfunction may also be enhanced. Beta-Blockers may enhance the rebound hypertensive effect of Alpha2-Agonists. This effect can occur when the Alpha2-Agonist is abruptly withdrawn. Management: Closely monitor heart rate during treatment with a beta blocker and clonidine. Withdraw beta blockers several days before clonidine withdrawal when possible, and monitor blood pressure closely. Recommendations for other alpha2-agonists are unavailable. Exceptions: Levobunolol; Metipranolol. Consider therapy modification

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

Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Consider therapy modification

Bradycardia-Causing Agents: May enhance the bradycardic effect of other Bradycardia-Causing Agents. Monitor therapy

Brexanolone: CNS Depressants may enhance the CNS depressant effect of Brexanolone. Monitor therapy

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 CNS depressant effect of CNS Depressants. Monitor therapy

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

Bromopride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromperidol: Blood Pressure Lowering Agents may enhance the hypotensive effect of Bromperidol. Bromperidol may diminish the hypotensive effect of Blood Pressure Lowering Agents. Avoid combination

Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Consider therapy modification

Calcium Channel Blockers (Nondihydropyridine): CloNIDine may enhance the AV-blocking effect of Calcium Channel Blockers (Nondihydropyridine). Sinus node dysfunction may also be enhanced. 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

Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Cannabis: May enhance the CNS depressant effect of CNS Depressants. 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: CloNIDine may enhance the AV-blocking effect of Cardiac Glycosides. Sinus node dysfunction may also be enhanced. Monitor therapy

Ceritinib: Bradycardia-Causing Agents may enhance the bradycardic effect of Ceritinib. Management: If this combination cannot be avoided, monitor patients for evidence of symptomatic bradycardia, and closely monitor blood pressure and heart rate during therapy. Exceptions are discussed in separate monographs. Consider therapy modification

Chlormethiazole: May enhance the CNS depressant effect of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Consider therapy modification

Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. 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

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

Dexmethylphenidate: May diminish the therapeutic effect of Antihypertensive Agents. 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

Dichlorphenamide: Thiazide and Thiazide-Like Diuretics may enhance the hypokalemic effect of Dichlorphenamide. Monitor therapy

Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. 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. Management: Although hydrochlorothiazide is specifically cited as a contraindication, the risk likely extends to all thiazide and thiazide-like diuretics and may be even greater with chlorthalidone or bendroflumethiazide. Consider alternatives when possible. Consider therapy modification

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Consider therapy modification

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

EPHEDrine (Systemic): CloNIDine may enhance the therapeutic effect of EPHEDrine (Systemic). Monitor therapy

Esketamine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Fexinidazole [INT]: Thiazide and Thiazide-Like Diuretics may enhance the arrhythmogenic effect of Fexinidazole [INT]. Avoid combination

Fexinidazole [INT]: Bradycardia-Causing Agents may enhance the arrhythmogenic effect of Fexinidazole [INT]. Avoid combination

Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification

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

HYDROcodone: CNS Depressants may enhance the CNS depressant effect of HYDROcodone. Management: Avoid concomitant use of hydrocodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

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

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

Ivabradine: Bradycardia-Causing Agents may enhance the bradycardic effect of Ivabradine. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Lacosamide: Bradycardia-Causing Agents may enhance the AV-blocking effect of Lacosamide. Monitor therapy

Lemborexant: May enhance the CNS depressant effect of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Consider therapy modification

Levodopa-Containing Products: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa-Containing Products. 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

Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Monitor therapy

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

Macimorelin: CloNIDine may diminish the diagnostic effect of Macimorelin. Avoid combination

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

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

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

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification

Methylphenidate: May enhance the adverse/toxic effect of CloNIDine. Monitor therapy

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

Midodrine: May enhance the bradycardic effect of Bradycardia-Causing Agents. Monitor therapy

Minocycline (Systemic): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirtazapine: May diminish the antihypertensive effect of Alpha2-Agonists. Management: Consider avoiding concurrent use. If the combination cannot be avoided, monitor for decreased effects of alpha2-agonists if mirtazapine is initiated/dose increased, or increased effects if mirtazapine is discontinued/dose decreased. Consider therapy modification

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

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

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

Neuromuscular-Blocking Agents (Nondepolarizing): Thiazide and Thiazide-Like Diuretics may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents (Nondepolarizing). Monitor therapy

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

Opioid Agonists: CNS Depressants may enhance the CNS depressant effect of Opioid Agonists. Management: Avoid concomitant use of opioid agonists and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

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

Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

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

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

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

Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Monitor therapy

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

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. 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

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

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Ruxolitinib: May enhance the bradycardic effect of Bradycardia-Causing Agents. Management: Ruxolitinib Canadian product labeling recommends avoiding use with bradycardia-causing agents to the extent possible. Monitor therapy

Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy

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

Serotonin/Norepinephrine Reuptake Inhibitors: May diminish the antihypertensive effect of Alpha2-Agonists. Monitor therapy

Siponimod: Bradycardia-Causing Agents may enhance the bradycardic effect of Siponimod. Management: Avoid coadministration of siponimod with drugs that may cause bradycardia. Consider therapy modification

Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. 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

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tapentadol: May enhance the CNS depressant effect of CNS Depressants. Management: Avoid concomitant use of tapentadol and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Terlipressin: May enhance the bradycardic effect of Bradycardia-Causing Agents. Monitor therapy

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Tetrahydrocannabinol and Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Tofacitinib: May enhance the bradycardic effect of Bradycardia-Causing Agents. 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

Tricyclic Antidepressants: May diminish the antihypertensive effect of Alpha2-Agonists. Management: Consider avoiding this combination. If used, monitor for decreased effects of the alpha2-agonist. Exercise great caution if discontinuing an alpha2-agonist in a patient receiving a TCA. Consider therapy modification

Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. 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

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification

Adverse Reactions

The following adverse reactions have been reported with the combination product. Also see individual agents.

>10%:

Central nervous system: Drowsiness (33%), dizziness (16%)

Gastrointestinal: Xerostomia (40%)

1% to 10%:

Central nervous system: Sedation (10%)

Gastrointestinal: Constipation (10%)

Warnings/Precautions

Concerns related to adverse effects:

• Bradycardia: Clonidine may cause dose-dependent reductions in heart rate; use with caution in patients with preexisting bradycardia or those predisposed to developing bradycardia.
• CNS depression: Clonidine may cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Electrolyte disturbances: Chlorthalidone may cause hypokalemia, hypochloremic alkalosis, or hyponatremia.
• Photosensitivity: Chlorthalidone may cause photosensitization.
• Rash: Patients using transdermal clonidine who have experienced allergic reactions (eg, generalized rash, urticaria, angioedema) may also experience rash and similar reactions following subsequent substitution of oral therapy.
• Sulfonamide (“sulfa”) allergy: The FDA-approved product labeling for many medications containing a sulfonamide chemical group includes a broad contraindication in patients with a prior allergic reaction to sulfonamides. There is a potential for cross-reactivity between members of a specific class (eg, two antibiotic sulfonamides). However, concerns for cross-reactivity have previously extended to all compounds containing the sulfonamide structure (SO₂NH₂). An expanded understanding of allergic mechanisms indicates cross-reactivity between antibiotic sulfonamides and nonantibiotic sulfonamides may not occur or at the very least this potential is extremely low (Brackett 2004; Johnson 2005; Slatore 2004; Tornero 2004). In particular, mechanisms of cross-reaction due to antibody production (anaphylaxis) are unlikely to occur with nonantibiotic sulfonamides. T-cell-mediated (type IV) reactions (eg, maculopapular rash) are less well understood and it is not possible to completely exclude this potential based on current insights. In cases where prior reactions were severe (Stevens-Johnson syndrome/TEN), some clinicians choose to avoid exposure to these classes.

Disease-related concerns:

• Bariatric surgery: Dehydration: Avoid diuretics in the immediate postoperative period after bariatric surgery; electrolyte disturbances and dehydration may occur. Diuretics may be resumed, if indicated, once oral fluid intake goals are met (Ziegler 2009).
• Cardiovascular disease: Use clonidine with caution in patients with severe coronary insufficiency, including recent MI and conduction disturbances, such as sinus node dysfunction.
• Cerebrovascular disease: Use clonidine with caution in patients with cerebrovascular disease.
• Diabetes: Use chlorthalidone with caution in patients with prediabetes or diabetes mellitus; may see a change in glucose control.
• Gout: Chlorthalidone can precipitate gout in certain patients with a history of gout, a familial predisposition to gout, or chronic renal failure.
• Hepatic impairment: Use chlorthalidone with caution in patients with severe hepatic dysfunction; in cirrhosis, avoid electrolyte and acid/base imbalances that may lead to hepatic coma.
• Hypercalcemia: Thiazide diuretics may decrease renal calcium excretion; consider avoiding use of chlorthalidone in patients with hypercalcemia.
• Hypercholesterolemia: Use with caution in patients with moderate or high cholesterol concentrations.
• Hypokalemia: Use chlorthalidone with caution in patients with hypokalemia; correct before initiating therapy.
• Renal impairment: Avoid chlorthalidone in severe renal disease (ineffective); use clonidine with caution in patients with chronic renal impairment.
• Systemic lupus erythematosus (SLE): Chlorthalidone is structurally related to thiazide diuretics which have been associated with SLE exacerbation or activation.

Concurrent drug therapy issues:

• Agents with SA/AV nodal blocking properties: Use clonidine with caution in patients concurrently receiving agents known to reduce SA node function and/or AV nodal conduction (eg, digoxin, diltiazem, metoprolol, verapamil); may increase risk of serious bradycardia.
• CNS depressants: Sedating effects of clonidine may be potentiated when used with other CNS-depressant drugs or ethanol.

Special populations:

• Surgical patients: Discontinue oral immediate release formulations within 4 hours of surgery, then restart as soon as possible afterwards.

Other warnings/precautions:

• Discontinuation of therapy: Gradual withdrawal of clonidine is needed (taper gradually over 2-4 days to avoid rebound hypertension) if drug needs to be stopped. Patients should be instructed about abrupt discontinuation (causes rapid increase in BP and symptoms of sympathetic overactivity).

Monitoring Parameters

Serum electrolytes, renal function; blood pressure, heart rate, fluid status

Pregnancy

Pregnancy Risk Factor

C

Pregnancy Considerations

Adverse events have been observed in some animal reproduction studies. Refer to individual monographs.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience constipation, nausea, vomiting, lack of appetite, abdominal cramps, diarrhea, headache, fatigue, or dry mouth. Have patient report immediately to prescriber signs of high blood sugar (confusion, fatigue, increased thirst, increased hunger, passing a lot of urine, flushing, fast breathing, or breath that smells like fruit), signs of fluid and electrolyte problems (mood changes, confusion, muscle pain or weakness, abnormal heartbeat, severe dizziness or passing out, fast heartbeat, increased thirst, seizures, loss of strength and energy, lack of appetite, unable to pass urine or change in amount of urine passed, dry mouth, dry eyes, or nausea or vomiting), signs of kidney problems (unable to pass urine, blood in the urine, change in amount of urine passed, or weight gain), signs of pancreatitis (severe abdominal pain, severe back pain, severe nausea, or vomiting), yellow skin, burning or numbness feeling, chills, severe sore throat, bruising, bleeding, severe loss of strength and energy, agitation, severe dizziness, passing out, or vision changes (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.