Drug Class: Aminoglycoside Antibiotic | Form: Intramuscular (IM) / Intravenous (IV) Injection | Prescription Status: Prescription Only (Rx) — DRAP Registered
What is Grasil 100mg Injection?
Grasil 100mg Injection contains Amikacin Sulphate — a powerful aminoglycoside antibiotic in a mid-strength formulation delivering 100mg of Amikacin per vial. This strength bridges the gap between the paediatric 50mg vial and the higher-strength adult formulations — making it particularly suitable for older children, adolescents, and smaller adults whose weight-based dose calculations require volumes that are most accurately and conveniently measured from a 100mg vial.
Amikacin is among the most broad-spectrum aminoglycosides available and is specifically valued for its reliable activity against multi-drug resistant (MDR) Gram-negative bacteria — including resistant Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter species — organisms responsible for some of the most difficult-to-treat serious infections encountered in Pakistani hospitals. Its modified chemical structure makes it resistant to most bacterial enzymes that inactivate Gentamicin and Tobramycin, preserving its effectiveness where other aminoglycosides have failed.
Grasil 100mg is strictly a hospital-only medicine with a well-defined and serious toxicity profile — particularly nephrotoxicity (kidney damage) and ototoxicity (irreversible hearing loss). Mandatory therapeutic drug monitoring, kidney function surveillance, and close clinical supervision are non-negotiable requirements throughout the entire treatment course.
What is Grasil 100mg Injection Used For?
Grasil 100mg Injection is approved for short-term treatment of the following serious bacterial infections caused by susceptible organisms:
- Respiratory tract infections — severe bacterial pneumonia and lower respiratory tract infections caused by Gram-negative organisms resistant to standard antibiotics (پھیپھڑوں کا شدید انفیکشن)
- Urinary tract infections — complicated UTIs and pyelonephritis caused by multi-drug resistant bacteria unresponsive to oral or standard injectable antibiotics (گردے اور پیشاب کی نالی کا شدید انفیکشن)
- Septicaemia — life-threatening bacterial bloodstream infection requiring immediate high-concentration antibiotic therapy (خون کا شدید بیکٹیریل انفیکشن)
- Bone and joint infections — osteomyelitis and septic arthritis caused by susceptible Gram-negative or Gram-positive organisms (ہڈی اور جوڑ کا انفیکشن)
- Intra-abdominal infections — peritonitis and abdominal cavity infections, typically used as part of combination antibiotic therapy alongside anaerobic coverage
- Skin and soft tissue infections — serious infections involving susceptible organisms not responding to standard antibiotic treatment (جلد کا شدید انفیکشن)
- Multi-drug resistant infections — infections caused by organisms confirmed resistant to other antibiotic classes where Amikacin sensitivity is demonstrated on culture and sensitivity testing
How Does Grasil 100mg Injection Work?
Amikacin kills bacteria through a precise and irreversible attack on bacterial protein synthesis — the process bacteria depend on to produce the proteins essential for their structure, function, and reproduction.
Once Amikacin enters the bacterial cell, it binds permanently to the 30S ribosomal subunit — the molecular machinery bacteria use to assemble proteins from amino acid building blocks. This permanent binding corrupts the protein production process, causing bacteria to manufacture defective, non-functional proteins. Without correctly functioning proteins, bacteria cannot maintain cell membrane integrity, regulate vital internal processes, or reproduce — leading to rapid and complete bacterial cell death.
This makes Amikacin bactericidal — actively killing bacteria rather than merely slowing their growth — which is clinically critical for life-threatening infections where rapid bacterial eradication is essential. Its chemically modified structure resists the aminoglycoside-inactivating enzymes produced by many resistant bacteria — explaining its superior and preserved effectiveness against MDR organisms where Gentamicin and Tobramycin have lost activity.
Administered by injection, Amikacin achieves immediate systemic distribution — reaching infected lungs, bloodstream, kidneys, bone tissue, and abdominal cavity within minutes, entirely bypassing the gastrointestinal system.
Dosage and Administration
⚠️ Grasil 100mg Injection is a hospital-only medicine. All doses must be individually calculated based on body weight and kidney function. Therapeutic drug monitoring is mandatory throughout treatment. Must be prepared and administered exclusively by qualified healthcare professionals.
| Patient Group | Dose | Frequency | Typical Duration |
|---|---|---|---|
| Older children (weight-based) | 15 – 22.5mg/kg/day | Divided every 8 hours | 7 – 10 days |
| Adolescents and smaller adults | 15mg/kg/day | Every 8 – 12 hours or once daily | 7 – 10 days |
| Adults (once-daily dosing) | 15 – 20mg/kg | Once daily | Maximum 10 days |
| Complicated UTI (adults) | 7.5mg/kg | Every 12 hours | 7 – 10 days |
| Kidney-impaired patients | Dose reduction and extended intervals essential | As calculated | Individually determined |
Administration Guidelines:
- Administer IV doses as a slow infusion over 30 to 60 minutes — never as a rapid IV bolus
- For IM use, inject deep into a large muscle with strict site rotation between doses
- Therapeutic drug monitoring (TDM) is mandatory — peak and trough Amikacin blood levels must be measured and doses individually adjusted
- Kidney function must be tested before starting and monitored every 2 to 3 days throughout treatment
- Maintain adequate patient hydration throughout — dehydration dramatically increases nephrotoxicity risk
- Maximum treatment duration is 10 days — prolonged courses significantly increase the risk of permanent hearing and kidney damage
Active Ingredient
| Ingredient | Strength per Vial |
|---|---|
| Amikacin Sulphate | 100mg |
Who Should NOT Receive Grasil 100mg Injection?
Do not administer if the patient:
- Is allergic to Amikacin or any other aminoglycoside antibiotic
- Has a history of aminoglycoside-induced hearing loss, tinnitus, or severe kidney damage
- Has myasthenia gravis — aminoglycosides severely worsen neuromuscular blockade and can precipitate respiratory failure
Always inform the treating doctor before administration if the patient has:
- Any degree of kidney impairment — dose reduction and extended dosing intervals are mandatory; Amikacin is eliminated entirely through the kidneys
- Pre-existing hearing loss or tinnitus — existing inner ear damage substantially increases ototoxicity risk
- Dehydration or reduced blood volume — correct fluid status before starting; dehydration dramatically concentrates Amikacin in kidney and ear tissue
- Neuromuscular disorders — increased risk of dangerous neuromuscular blockade
- Is pregnant — Amikacin crosses the placenta and can cause permanent congenital deafness; use only when no safer alternative exists for a life-threatening infection
- Is elderly — age-related kidney decline substantially increases both nephrotoxicity and ototoxicity risk
Side Effects
Amikacin has a narrow therapeutic window — the difference between an effective and a toxic dose is small. The two most serious risks — kidney damage and irreversible hearing loss — require active monitoring throughout the entire course.
Common Side Effects:
- Injection site pain, redness, or localised swelling
- Mild nausea or vomiting
- Headache or mild dizziness
The Two Critical Toxicities:
🔴 Nephrotoxicity (Kidney Damage) — Amikacin accumulates in kidney tubule cells causing direct damage — presenting as rising creatinine, reduced urination, and electrolyte disturbances. Kidney function tests before and every 2 to 3 days during treatment are mandatory. When detected early and treatment is modified, nephrotoxicity is usually reversible — but can progress to acute kidney failure if missed.
🔴 Ototoxicity (Irreversible Hearing and Balance Damage) — Amikacin concentrates in inner ear fluid (کان کا اندرونی حصہ) and permanently destroys cochlear hair cells — causing irreversible high-frequency hearing loss (بہرا پن) that may not become apparent until after treatment ends. Balance damage causing persistent dizziness can also occur. Unlike kidney damage, hearing loss from Amikacin cannot be reversed. Report any ringing in the ears, muffled hearing, or new dizziness to the medical team immediately — do not wait until the next scheduled review.
Other Serious Side Effects:
- Neuromuscular blockade — rare but potentially fatal respiratory paralysis, particularly in patients with neuromuscular disorders or those receiving anaesthetic agents
- Severe allergic reaction — sudden rash, facial swelling, difficulty breathing — emergency treatment required (یہ طبی ہنگامی صورتحال ہے)
- Electrolyte disturbances — low potassium, magnesium, or calcium from kidney tubule damage requiring monitoring and replacement
Drug Interactions
| Medicine / Substance | Possible Interaction |
|---|---|
| Other aminoglycosides (e.g., Gentamicin, Tobramycin) | Never combine — additive and severe kidney and hearing toxicity |
| Loop diuretics (e.g., Furosemide) | Dramatically increases irreversible hearing toxicity — avoid; if unavoidable, audiological monitoring is mandatory |
| Vancomycin | Additive nephrotoxicity — one of the most dangerous combinations clinically; mandatory kidney function monitoring |
| Beta-lactam antibiotics (e.g., Piperacillin, Ampicillin) | Never mix in the same syringe or IV bag — chemical inactivation of both medicines occurs; administer through separate lines |
| NSAIDs (e.g., Diclofenac, Ibuprofen) | Reduce kidney blood flow — increase Amikacin accumulation and nephrotoxicity risk |
| Neuromuscular blocking agents (e.g., Vecuronium) | Amikacin potentiates blockade — risk of prolonged respiratory paralysis; anaesthetist must be informed |
| Ciclosporine and Tacrolimus | Additive nephrotoxicity — close kidney function monitoring required |
| Cisplatin (cancer medicine) | Additive hearing and kidney toxicity — avoid concurrent use |
| Amphotericin B (antifungal) | Additive nephrotoxicity — use together only when no safer alternative exists |
Storage Instructions
- Store below 25°C in a cool, dry place protected from direct light
- Do not freeze — freezing alters solution integrity
- Keep in original packaging until immediately before use
- Keep out of reach of children (بچوں کی پہنچ سے دور رکھیں)
- Inspect vial before use — solution must be clear and colourless to pale yellow; discard if discoloured or particles are present
- Use immediately once opened — never store a partially used vial
- Do not use after the expiry date on the vial or outer carton
Frequently Asked Questions
Why is the 100mg vial used instead of the 50mg or higher-strength formulations?
The 100mg vial is designed for older children, adolescents, and smaller adults whose weight-based dose calculations result in volumes most accurately and safely measured from a 100mg vial. Using the 50mg vial for these patients would require multiple vials per dose — increasing preparation time and the risk of calculation errors. Using a higher-concentration adult vial would require very small, difficult-to-measure volumes — equally increasing dosing error risk. The 100mg vial provides the most practical and accurate dosing option for this intermediate weight range of patients.
What makes Amikacin effective against infections where Gentamicin has failed?
Bacteria develop resistance to aminoglycosides primarily by producing enzymes that chemically modify and inactivate the antibiotic molecule. Most of these resistance enzymes were originally evolved against older aminoglycosides like Gentamicin and Tobramycin. Amikacin's chemical structure contains modifications that physically block most of these inactivating enzymes from binding to it — meaning the majority of Gentamicin-resistant organisms cannot inactivate Amikacin by the same mechanism. This is why Amikacin retains activity against many MDR Gram-negative organisms and is specifically reserved for situations where other aminoglycosides and many other antibiotic classes have lost effectiveness.
How serious is the risk of permanent hearing loss with Grasil 100mg?
Ototoxicity is the most serious long-term concern with Amikacin therapy and must be fully understood. Amikacin accumulates in the cochlear fluid of the inner ear and progressively destroys hair cells — the specialised sensory cells that convert sound vibrations into nerve signals. These cells do not regenerate in humans — meaning any hearing loss caused is permanent and cannot be treated or reversed with any currently available medicine or therapy. The damage typically begins at high frequencies — which may not be immediately noticeable in everyday conversation — before progressing to affect speech-range hearing. Any ringing in the ears (tinnitus), perception of muffled sounds, or difficulty hearing during treatment must be reported to the doctor immediately without waiting.
What happens if a Grasil dose is given too quickly by IV?
Rapid IV bolus injection of Amikacin — rather than the required 30 to 60-minute slow infusion — causes a sudden, very high peak drug concentration in the bloodstream. This peak surge dramatically increases the concentration of Amikacin delivered to kidney tubule cells and inner ear fluid in a short time, substantially raising the risk of both acute nephrotoxicity and cochlear hair cell damage compared to the same total dose administered slowly. The 30 to 60-minute infusion time is specifically designed to limit peak concentrations to levels that are therapeutically effective without exceeding the toxic threshold. Administering Amikacin as a slow infusion is a non-negotiable clinical safety requirement.
Can Grasil 100mg be used safely alongside Vancomycin?
The combination of Amikacin and Vancomycin is considered one of the highest-risk antibiotic combinations in clinical practice specifically because both medicines are independently nephrotoxic — and their kidney-damaging effects are directly additive when combined. This combination is sometimes clinically unavoidable in serious MDR infections requiring both agents, but it must only be used under specialist infectious disease supervision with very frequent kidney function monitoring — ideally daily serum creatinine measurements. Therapeutic drug monitoring for both Amikacin and Vancomycin simultaneously is mandatory, and the patient must be kept well hydrated throughout to minimise the combined kidney damage risk.
What should be done if a patient on Grasil develops significantly reduced urination?
Significantly reduced urination during Amikacin treatment is a warning sign of developing nephrotoxicity and must be reported to the medical team immediately — do not wait until the next scheduled kidney function test. The team will measure creatinine and urine output urgently, review the current Amikacin dose and interval, assess the patient's hydration status, and check for other concurrent nephrotoxic medicines. Depending on findings, Amikacin may be dose-reduced, the dosing interval extended, or treatment temporarily or permanently discontinued. Early detection and prompt dose modification significantly increase the chances of kidney function recovery.
⚕️ Medical Disclaimer: This product description is provided for general informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Grasil 100mg Injection is a prescription-only hospital medicine requiring mandatory therapeutic drug monitoring and continuous kidney function surveillance throughout treatment. It must be administered exclusively by qualified healthcare professionals. Report any new hearing changes, tinnitus, reduced urination, or muscle weakness to the medical team immediately.
DRAP Registered | Prescription Required (Rx) | Hospital use only — mandatory kidney function and drug level monitoring throughout treatment — report any hearing changes or reduced urination immediately