N-ASPA

• Spasmolytic Agent:
• Relief of smooth muscle spasm associated with:
• Biliary colic
• Renal colic
• Gastrointestinal spasms (e.g., irritable bowel syndrome)
• Uterine smooth muscle spasms (e.g., dysmenorrhea, labor augmentation support)
• Postoperative spasms
• Adjunct Treatment:
• Used to facilitate diagnostic or therapeutic procedures requiring muscle relaxation.
• Off-label Uses:
• Management of smooth muscle spasm-related pain in genitourinary tract disorders.
• Relief of spasmodic pain in gastrointestinal motility disorders.

Adults:

• Oral:
  Typical dose is 40–80 mg three times daily.
  Maximum daily dose: 240 mg.
• Intramuscular (IM) or Intravenous (IV) Injection:
  40 mg administered 2–3 times daily for rapid relief of acute spasm.
• Duration:
  Use for the shortest duration necessary to control symptoms. Usually treatment duration ranges from a few days to 2 weeks, depending on clinical response.

Pediatrics:

• Safety and efficacy not well established; use only if clearly indicated and under medical supervision.

Elderly:

• Use with caution; start with lower doses considering renal and hepatic function.

Renal/Hepatic Impairment:

• Dose adjustment may be required; caution advised.

Drotaverine hydrochloride is a selective inhibitor of phosphodiesterase-4 (PDE-4) enzyme in smooth muscle cells. By inhibiting PDE-4, it increases intracellular cyclic adenosine monophosphate (cAMP) levels, leading to relaxation of smooth muscles by reducing calcium ion influx and sensitivity. This relaxation reduces spasms and associated pain in smooth muscle-rich organs such as the gastrointestinal tract, biliary system, urinary tract, and uterus without affecting skeletal or cardiac muscles.

• Absorption:
  Rapidly absorbed orally with peak plasma concentrations reached within 45 minutes to 1 hour.
• Bioavailability:
  Approximately 40–50% due to first-pass metabolism.
• Distribution:
  Widely distributed with a volume of distribution around 2–4 L/kg.
  Plasma protein binding is moderate (~70%).
• Metabolism:
  Extensively metabolized in the liver primarily via demethylation and conjugation.
• Half-life:
  Approximately 7–16 hours depending on individual metabolism.
• Elimination:
  Excreted mainly via urine as metabolites; small amounts eliminated unchanged in feces.

• Pregnancy:
  Limited data in humans. Use only if potential benefits justify the potential risk. Classified as Category C (risk cannot be ruled out).
• Lactation:
  Unknown whether drotaverine is excreted in human milk. Caution advised; breastfeeding mothers should consult healthcare provider.

• Primary Class: Antispasmodic / Spasmolytic Agent
• Subclass: Phosphodiesterase-4 (PDE-4) inhibitor; smooth muscle relaxant

• Known hypersensitivity to drotaverine or any excipients
• Severe hepatic impairment
• Severe renal impairment
• Cardiovascular instability or severe hypotension
• Mechanical obstruction of the gastrointestinal or urinary tract
• Pregnancy (unless clearly justified)
• Lactation (use caution)

• Use cautiously in patients with cardiovascular disorders; may cause hypotension.
• Monitor for signs of allergic reactions or hypersensitivity.
• Not recommended for prolonged use without medical supervision.
• Caution in patients with hepatic or renal dysfunction; dose adjustment may be necessary.
• May mask symptoms of underlying conditions requiring further evaluation.

Common:

• Headache
• Dizziness
• Flushing
• Nausea
• Dry mouth

Less Common / Rare:

• Hypotension
• Allergic skin reactions (rash, itching)
• Palpitations
• Tremor
• Elevated liver enzymes (rare)

• Antihypertensive Drugs:
  Additive hypotensive effect possible.
• Other PDE Inhibitors:
  Concurrent use may potentiate effects on smooth muscle relaxation.
• CYP450 Modulators:
  Potential interaction with drugs that induce or inhibit hepatic enzymes affecting metabolism.
• Alcohol:
  May increase hypotensive and sedative effects.

• Recent clinical guidelines emphasize drotaverine’s role as a preferred antispasmodic for biliary and renal colic due to favorable safety and efficacy profiles.
• No major changes in dosing or indications reported in the last 5 years.
• Monitoring recommendations highlight cautious use in renal and hepatic impairment.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and direct sunlight.
• Keep in original packaging until use.
• Keep out of reach of children.
• No special refrigeration required.