Methyclothiazide

Oral
Oedema

Oral
Hypertension

Hypersensitivity to sulfonamide-derived drugs, anuria.

Patient w/ fluid and electrolyte disturbances, gout, DM, hypercholesterolaemia, parathyroid disease, history of allergy and bronchial asthma. May exacerbate SLE. Hepatic and renal impairment. Pregnancy and lactation.

Headache, cramping, weakness, orthostatic hypotension, pancreatitis, jaundice, sialadenitis, vomiting, diarrhoea, nausea, gastric irritation, constipation, anorexia, aplastic anaemia, haemolytic anaemia, agranulocytosis, leukopenia, thrombocytopenia, anaphylactic reactions, necrotising angiitis, Stevens-Johnson syndrome, resp distress, fever, purpura, urticaria, rash, photosensitivity, hyperglycemia, hyperuricemia, electrolyte imbalance, vertigo, dizziness, paraesthesia, muscle spasm, restlessness, transient blurred vision, xanthopsia, glycosuria.

PO: B

Assess wt, input and output reports daily to determine fluid loss, BP, serum electrolytes, BUN, creatinine.

Symptoms: Electrolyte imbalance and signs of K deficiency (e.g. confusion, dizziness, muscular weakness, GI disturbances). Management: General supportive measures including replacement of fluids and electrolytes.

Increased risk of lithium toxicity. Hypokalaemia may develop during concomitant use of steroids or ACTH. Insulin requirement in DM patients may be altered. Decreased arterial responsiveness to norepinephrine. Increased responsiveness to tubocurarine. Potentiation of orthostatic hypotension by barbiturates or narcotics.

Avoid alcohol as it may potentiate orthostatic hypotension.

May interfere w/ tests for parathyroid function. May decrease serum protein-bound iodine (PBI) levels w/o signs of thyroid disturbance.

Description:
Mechanism of Action: Methyclothiazide inhibits Na reabsorption in the distal tubules causing increased excretion of Na and water, as well as K and hydrogen ions.
Onset: Approx 2 hr.
Duration: ≥24 hr.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract. Time to peak plasma concentration: 6 hr.
Distribution: Crosses the placenta and excreted in breast milk.
Excretion: Via urine as unchanged drug.

Store between 20-25°C. Protect from light and moisture.

Diuretics

Anon. Methyclothiazide. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/06/2014.

Buckingham R (ed). Methyclothiazide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/06/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Methyclothiazide. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/06/2014.

Methyclothiazide tablet (Mylan Pharmaceuticals Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/06/2014.

Wickersham RM. Methyclothiazide. Facts and Comparisons [online]. St. Louis, MO. Wolters Kluwer Clinical Drug Information, Inc. https://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed 04/06/2014.