Linestat (Orlistat)

Linestat, an oral lipase inhibitor, is indicated for conditions where reduction of dietary fat absorption supports weight control.

• Obesity: assists adults with a body‑mass index (BMI) ≥30 in achieving weight loss when combined with a reduced‑calorie diet.
• Overweight: aids weight management in adults with BMI ≥25 who have weight‑related risk factors.
• Weight management in comorbid conditions: helps patients with obesity‑related hypertension or dyslipidaemia to improve overall health outcomes.

• Orlistat acts locally in the gastrointestinal tract by covalently binding to the active site of gastric and pancreatic lipases. This inhibition prevents the hydrolysis of dietary triglycerides into absorbable free fatty acids, thereby reducing the amount of fat absorbed (approximately 30%) and increasing fecal fat excretion. The effect is confined to the lumen of the gut and does not involve systemic absorption of the drug.

Orlistat’s safety profile is characterised primarily by gastrointestinal events due to unabsorbed fat.

Common Side Effects

• Oily spotting on undergarments: visible oil after defecation.
• Flatulence with discharge: gas accompanied by oily stool.
• Fecal urgency: sudden need to defecate.
• Increased defecation frequency: more bowel movements.
• Abdominal pain or cramping.
• Oily or fatty stool.

Serious or Rare Side Effects

• Liver injury: rare cases of hepatitis.
• Severe allergic reactions: rash, swelling, or anaphylaxis.
• Pancreatitis: inflammation of the pancreas.
• Fat‑soluble vitamin deficiency: reduced absorption of vitamins A, D, E, K.
• Acute kidney injury: very rare reports.
• Stevens‑Johnson syndrome: severe skin reaction.

Before initiating Linestat, clinicians should consider several safety measures.

• BMI assessment: confirm patient meets obesity or overweight criteria.
• Low‑fat diet: advise a diet containing ≤30% of total calories from fat.
• Gastrointestinal monitoring: watch for persistent oily stools or abdominal pain.
• Liver function: evaluate baseline hepatic enzymes in patients with liver disease.
• Vitamin supplementation: consider timed intake of fat‑soluble vitamins.
• Storage: Store below 25°C: keep in the original container, protect from moisture and direct sunlight.

Orlistat can alter the absorption of several co‑administered agents.

Major Interactions (Avoid)

• Cyclosporine: increased systemic exposure may raise toxicity risk.
• Warfarin: orlistat may enhance anticoagulant effect, leading to higher INR.
• Levothyroxine: reduced absorption can diminish thyroid hormone levels.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: possible decrease in efficacy; consider alternative methods.
• Fat‑soluble vitamins (A, D, E, K): timing of supplementation should be separated by at least 2 hours.
• Antacids containing aluminium or magnesium: may affect orlistat’s action.
• Other lipase inhibitors: additive effect on fat malabsorption.